Dissertations / Theses on the topic 'Advanced drug delivery systems'

This research explores the feasibility of the electrohydrodynamic processing using single and co-axial set-up as a single step processing tool for preparation of advanced drug delivery systems. A number of synthetic biodegradable and non-biodegradable polymers were used in order to prepare formulations incorporating drugs of different physicochemical characteristics. Based on the focus and the desired applications, the polymeric carrier and solvent system as well as the model drug of interest were selected to develop the drug delivery systems. Firstly, core-shell microparticles were prepared and optimized using co-axial electrohdrodynamic processing with precise control over the averaged particle size and size distribution. This was followed by integration of model drugs with different water-solubility. In this study, the release characteristics of the developed particles were investigated with single and simultaneous encapsulation of the drugs. Successful preparation of fixed dose combination formulation with high processing yield and encapsulation efficiency was reported. Secondly, single and co-axial electrohydrodynamic processing was utilized for preparation of smart drug delivery system for targeted release of prednisolone. Colon targeted drug delivery systems were developed using a pH-responsive polymer. Varying polymer drug ratio was applied to further enhance the release profiles and obtain an efficient delivery system whereby local delivery of prednisolone is made possible. Finally, microspheres were developed for co-encapsulation of anti-diabetic drugs with different water-solubility. The successfully developed sustained release formulations have the potential to overcome the existing limitations of conventional formulations by enhancing patient compliance and efficacy of the treatment of any chronic conditions.

In chapter two, the development of new a nanoparticulate carrier system for gene delivery was described. The new nanocarrier consists of a blend matrix formed by a poly (lactic-eo-glycolic acid) (PLGA) and Poly(ethylene glycol) bis (3-aminopropyl) terminated (also known as JeffamineTM). Nanopartic1es were formulated based on a 50:50 weight ratio of PLGA:Jeffamine using a modified emulsification-solvent diffusion technique. The potential of these blended matrix nanoparticles for encapsulation efficiency of Calf Thymus DNA and release profile were also studied. The achieved encapsulation efficiency of Calf Thymus DNA was approximately 84% for 0.4% theoretical loading with regard to total amount of PLGA. The PLGA: Jeffamine blended nanoparticles provided continuous and controlled release of Calf Thymus DNA. The PLGA:Jeffamine nanopartic1es were also coated with PLGA-PEGMA&75and PDMAEMA-PEGMA block copolymers using a simple physical adsorption method. After surface coating of the nanoparticles, zeta potential value showed significant reduction of surface charges from -38 mV to near zero value, while TEM micrographs showed a well defined core-shell nanoparticle. In chapter three, A facile route to biocompatible poly (lactic acid-coglycolic acid)-co-poly (ethyleneglycol methacrylate) (PLGA-PEGMA) block co-polymers was described utilising a combination of ring-opening polymerisation (ROP) and Radical Addition Fragmentation Transfer (RAFT) methods. A series of PLGA-PEGMA polymers varying in comonomer content and block length were synthesised with low polydispersities. All the block co-polymers formed micelles in aqueous solution as shown by dynamic light scattering, while critical micelle concentrations were found to be in the micromolar range. The polymer micelles were able to encapsulate model drugs(carboxyfluorescein and fluorescein isothiocyanate) and selected copolymer micelles incubated with 3T3 fibroblasts as a model cell line were rapidly taken up as indicated by fluorescence microscopy assays. The combination of the polymer chemistries opens the way to highly flexible syntheses of micellar drug carrier systems. In chapter four, multifunctional and modular block co-polymers prepared from biocompatible monomers and linked by a bioreducible disulphide linkage have been prepared using a combination of ring-opening and atom-transfer radical polymerizations (ATRP). The presence of terminal functionality via ATRP allowed cell-targeting folic acid groups to be attached in a controllable manner, while the block co-polymer architecture enabled well-defined nanopartic1es to be prepared by a water-oil-water double emulsion procedure to encapsulate DNA with high efficiency. Gene delivery assays in a Calu-3 cell line indicated specific folatereceptor-mediated uptake of the nanoparticles, and triggered release of the DNA payload via cleavage of the disulfide link resulted in enhanced transgene expression compared to non-bioreducible analogues. These materials offer a promising and generic means to deliver a wide variety of therapeutic payloads to cells in a selective and tuneable way.

L’étude a portée sur le développement de micro- et nanoparticules polymères destinées à l’administration orale d’insuline. Une méthode de polymérisation radicalaire a été optimisée pour formuler des micro et des nanoparticules à base d’un polymère formant des hydrogels, le poly(acide de méthacrylique). Les particules ont ensuite été modifiées par greffage de résidus cystéine pour introduire des fonctions thiol en vue de renforcer les propriétés de bioadhésion et de promoteur d’adsorption des systèmes obtenus. Les particules ont montré des propriétés intéressantes de chargement en insuline et la libération se fait selon un mode de libération pH sensible. En effet, alors que l’insuline est majoritairement retenue dans la forme pharmaceutique à pH acide correspondant à un milieu gastrique, elle est libérée à un pH neutre voire légèrement basique retrouvé au niveau de l’intestin. Les systèmes ont montré une bonne capacité à améliorer le passage de l’épithélium intestinal sur des monocouches de cellules Caco 2 et sur de l’intestin isolé monté en chambres de Ussing. Au final, ces systèmes ont permis d’induire in vivo une réduction de la glycémie chez des animaux diabétiques et après une administration orale. Les essais menés sur des insulines modifiées ont permis d’identifier une stratégie de modification intéressante basée sur l’association de l’hormone à une cyclodextrine. En revanche, nos résultats suggèrent que la PEGylation de l’insuline n’apporte aucun bénéfice
The work carried out in this thesis was aimed to develop polymer micro- and nanoparticles for the oral administration of insulin. A method of radical polymerization was optimized to design micro and nanoparticles with a hydrogel forming polymer, poly(methacrylic acid) (PMAA). The particles were further modified by the grafting of cystein residues in order to introduce thiol functions which are believed to reinforce mucoadhesive and permeation enhancing properties of the formulation. The particles showed interesting loading properties for insulin and the release of the hormone was found to be pH dependent. Although insulin was mainly retained by the hydrogel particle in releasing medium mimicking the gastric environment, the hormone was released in conditions found in the intestine. The formulated systems have shown to improve the absorption of insulin through the intestinal mucosa in in vitro models including Caco 2 cell monolayers and the Ussing chambers. The microparticles selected from the in vitro experiments for in vivo studies have shown a capacity to deliver active insulin through the oral route to diabetic rats producing a reduction of the glycemia. Tests performed with modified insulin have allowed to identify that among the two strategies followed, this consisting on the association of insulin with a cyclodextrin was the most promising while the one based on the formation of an insulin-PEG conjugate did not brought any benefice

Metastastic breast cancer is one of the leading causes of cancer death among women worldwide. Bone metastases occur most frequently among breast cancer patients that significantly influence the patients’ quality of life and reduce their survival rate. Among all types of breast cancer, triple negative breast cancer (TNBC) is more aggressive and more likely to develop metastasis. Thus, a targeted preventative modality is highly demanded for this unmet challenge. Nanoparticles have been under investigation for a few decades and have shown ample potential for the treatment of challenging types of cancer. The utilisation of nanoparticles can alter the drugs’ pharmacokinetics via different mechanisms, including improvement of the poor solubility of hydrophobic drugs and reduction of the metabolism. Curcumin, an active ingredient of the herb Curcuma longa rhizome, has been proven to have anticancer activity in various cancers. However, due to its low aqueous solubility and poor stability, the clinical application of curcumin in cancer treatment has been limited. In this research, in order to overcome the challenges associated with the poor druggability of curcumin, we designed and fabricated two different types of nanoparticles: Pluronic® F127-based micelles (with/without D-α-Tocopherol polyethylene glycol 1000 succinate (TPGS)) and poly (lactic-co-glycolic acid) (PLGA) -based polymeric nanoparticles (NPs) aiming at preventing and treating breast cancer bone metastasis. A main focus of this study was the development of hybrid untargeted, mono- and dual-targeted delivery systems for curcumin. With Pluronic® F127-based micelles, a major focus went to optimise the fabrication process of the F127-TPGS NPs. The optimised fabrication method for hybrid F127-TPGS resulted in a very high reproducibility after n>3 repeats leading to a consistent size 26.42 ± 0.57 nm, zeta-potential around 0.39 ± 0.99 mV, and PDI around 0.2. The drug loading (the amount of drug loaded per unit weight of the nanoparticle) was achieved at 3.80 ± 0.18% and encapsulation efficiency (the percentage of drug that is successfully entrapped into the nanoparticles) of 63.40 ± 3.00%. Bone targeted nanoparticles exhibited a high affinity to hydroxyapatite, the mineral bone matrix indicating bone targeting potentials of these NPs. In vitro cytotoxicity studies resulted in IC50 values at low micromolar range for all nanoparticles (ranging from 5-10 µM). We further studied the in vivo antitumour and anti-metastastic activity of untargeted and bone-targeted nanoparticles fabricated with Pluronic® F127 only. The results indicated that both types of nanoparticles could improve the overall condition of tumour burdened mice and inhibit the metastases to the liver, plausibly via prevention of the tumour angiogenesis. F127-coated PLGA-based bone-targeted nanoparticles showed size 168.00 ± 1.42 nm, zeta-potential -2.83 ± 0.22 mV, and PDI around 0.2. The loading was achieved at 0.97 ± 0.11% and encapsulation efficiency of 0.97 ± 0.11%. The results of In vitro cytotoxicity studies indicated that the alendronate conjugation in these NPs could significantly reduce the cell viability in human MDA-MB-231 TNBC cells compared to the negative control and untargeted nanoparticles (p<0.0001). In conclusion, the hybrid Pluronic® F127-TPGS based micelles had considerably smaller size than the F127-coated PLGA based NPs. Yet, both NP sizes lie within the acceptable size range for cancer therapy. All types of NPs showed great physical stability, and biocompatibility. They could solve the poor aqueous solubility of curcumin, in addition to exerting potent antitumour effect in vitro. The results indicated that the two types of NPs described in this research are promising carriers to be developed for the selective delivery of various poorly water-soluble drugs and have great potential for further investigation.

[EN] The present PhD thesis, which is entitled "Design of new bio-gated nanodevices for advanced communication processes and targeted controlled release of therapeutic agents" is focused on the development of new functional hybrid organic-inorganic materials for applications in the field of the controlled delivery of target molecules. The first chapter of the present thesis gives an introduction to the organic-inorganic hybrid materials functionalized with "molecular gates" and its application in controlled release processes. The second chapter of this thesis is focused on the development of a new nanodevice able to deliver its cargo as a function of the glucose concentration. The nanodevice is based on mesoporous silica nanoparticles loaded with a suitable fluorophore and functionalized with propylbenzymidazole moieties on the pore outlets. The mesopores are then capped with an active cyclodextrin modified glucose oxidase enzyme (through the formation of an inclusion complex between the cyclodextrins and the propylbenzymidazole group anchored to the solid support). When glucose is added its enzymatic oxidation produced gluconic acid. This acid induced a decrease in the pH of the medium and the protonation of the benzymidazole group that might result in the inclusion complex dethreading and the subsequent cargo release. The third chapter of the thesis is focused on the development of a new redox-responsive material for the controlled delivery of cytotoxic drugs in cancer cells. The system is based on mesoporous silica nanoparticles loaded with a reporter (safranin O) and functionalized with two different sized polyethylene glycol chains in the pore outlets using a disulfide linkage. In presence of glutathione, the disulfide bonds are cleaved allowing the release of the entrapped cargo. Once confirmed the aperture protocol, the uptake of the gated nanoparticles and their ability to deliver the cargo (fluorophore or cytotoxic agent) in HeLa cells were tested. Moreover, cell viability assays were also performed. The fourth chapter of the thesis is focused on the preparation and the study of a nanodevice for the controlled delivery in senescent cells in a murine model of pulmonary fibrosis. The material is prepared using mesoporous silica nanoparticles (as an inorganic support) and galactoligosaccharide (molecular gate) moieties anchored on the external surface. In presence of senescent cells, which overexpress ß-galactosidase enzyme, the hydrolysis of the galactooligosaccharide capping molecules take place and the cargo release from the inner of the pores is produced (rhodamine B). After the in vitro studies, the ability of nanoparticles to accumulate and release their payload in tissues with abundance of senescent cells was evaluated in vivo. For that purpose, mice with induced pulmonary fibrosis, pathogenesis with associated increased alveolar senescence, were treated with the synthesized material and subsequently examined to assess its ability to accumulate and release its payload (fluorophore) in lung's damaged areas. In the fifth chapter of the thesis it has been explored the concept of cascade chemical communication using different types of nanodevices, each of them loaded with a certain messenger and externally functionalized with a gate-like entity that controls the release of the payload. When the enzyme able to hydrolyze the molecular gate that blocks the pores of the first type of nanoparticles (S1), is added to an aqueous suspension containing the three nanoparticles, the delivery of the chemical messenger 1 is produced. This messenger is able to open the second type of nanoparticles (S2) which delivers the messenger 2. Finally, the messenger 2 triggers the aperture of the third group of gated system (S3), which ultimately delivers its load (a dye) as a final response.
[ES] La presente tesis doctoral titulada "Diseño de nuevos nanodispositivos para procesos avanzados de comunicación y liberación controlada y dirigida de agentes terapéuticos" está centrada en el desarrollo de nuevos materiales híbridos orgánico-inorgánicos funcionales para aplicaciones en el campo de la liberación controlada de moléculas de interés. El primer capítulo de la tesis ofrece una introducción a los materiales híbridos orgánico-inorgánicos funcionalizados con "puertas moleculares" y su aplicación en procesos de liberación controlada. En el segundo capítulo de la tesis se aborda el desarrollo de un nanodispositivo capaz de responder y liberar su carga en función de la concentración de glucosa. Este nanodispositivo está basado en nanoparticulas de sílice mesoporosa funcionalizadas en su superficie externa con grupos benzimidazol y con los poros cargados con un fluoróforo. Los poros se cierran al añadir la enzima glucosa oxidasa funcionalizada con ciclodextrinas (por formación de un complejo de inclusión entre el benzimidazol y los oligosacáridos cíclicos). Al adicionar glucosa se produce su oxidación enzimática dando ácido glucónico. Este ácido induce una bajada del pH del medio con la consiguiente protonación de los benzimidazoles y la ruptura de los complejos de inclusión. Esta ruptura provoca la salida de la enzima de la superficie y la liberación del colorante atrapado en los poros. El tercer capítulo de la tesis se ha centrado en el desarrollo de un material para la liberación controlada de agentes citotóxicos en células cancerosas en respuesta a cambios en el potencial redox. De nuevo se emplean nanopartículas de sílice mesoporosa con los poros cargados con un colorante (safranina O) y la superficie externa funcionalizada con dos polietilenglicoles conteniendo enlaces disulfuro. En presencia de glutatión se produce la reducción del enlace disulfuro con la consiguiente liberación del colorante. Una vez confirmado el protocolo de apertura, se estudió la internalización y la liberación de un fluoróforo y de un agente citotóxico en el modelo celular HeLa, realizando además ensayos de viabilidad. En el cuarto capítulo de la tesis se ha preparado y ensayado un nanodispositivo para la liberación controlada en células senescentes en un modelo murino de fibrosis pulmonar. El material se prepara empleando nanopartículas de sílice mesoporosa y un galactooligosacárido anclado en la superficie externa. En presencia de células senescentes, que sobreexpresan la enzima ¿-galactosidasa, se produce la hidrólisis del oligosacárido con la consiguiente liberación de la carga atrapada en los poros del soporte (rodamina B). Tras los estudios in vitro, la capacidad del nanodispositivo de acumularse y liberar su carga en tejidos ricos en células senescentes se evaluó in vivo. Para ello, ratones con fibrosis pulmonar inducida, patología en la que se ha descrito la aparición de senescencia, se trataron con el material sintetizado y posteriormente fueron examinados para comprobar la capacidad de acumularse y liberar su carga (fluoróforo) en la zona pulmonar dañada. En el quinto capítulo se ha explorado el proceso de comunicación química en cascada empleando tres tipos de nanopartículas mesoporosas de sílice cargadas con diferentes mensajeros y funcionalizadas con tres puertas moleculares distintas. Cuando sobre una suspensión de las tres nanopartículas se añade la enzima capaz de hidrolizar la puerta molecular que bloquea los poros del primer tipo de nanopartículas (S1), se produce la liberación del mensajero 1. Este mensajero es capaz de inducir la apertura del segundo tipo de nanopartículas (S2), que a su vez liberan al medio el mensajero 2. Por último, el mensajero 2 es capaz de abrir la puerta molecular del tercer tipo de nanopartículas (S3), que liberan finalmente su carga (un colorante) como respuesta final.
[CAT] La present tesis doctoral titulada "Disseny de nous nanodispositius per a processos avançats de comunicació i lliberació controlada i dirigida d'agents terapèutics" està centrada en el desenvolupament de nous materials híbrids orgànic-inorgànic funcionals per a aplicacions en el camp de la lliberació controlada de molècules d'interès. El primer capítol de la tesis ofereix una introducció als materials híbrids orgànic-inorgànic funcionalitzats amb "portes moleculars" i la seua aplicació en processos de lliberació controlada. En el segon capítol de la tesis s'aborda el desenvolupament d'un nanodispositiu capaç de respondre i lliberar la seua càrrega en funció de la concentració de glucosa. Este nanodispositiu està basat en nanopartícules de sílice mesoporoses funcionalitzades a la seua superfície externa amb grups benzimidazol i amb els pors carregats amb un fluoròfor. Els pors queden bloquejats al afegir el enzim glucosa oxidasa funcionalitzada amb ciclodextrines (per formació d'un complex d'inclusió entre el benzimidazol i els oligosacàrids cíclics). Al afegir glucosa es produeix la seua oxidació enzimàtica donant lloc a àcid glucònic. Este àcid indueix una baixada del pH del medi amb la consegüent protonació dels benzimidazols i el trencament dels complexes d'inclusió. Este trencament provoca l'eixida del enzim de la superfície i la lliberació del colorant atrapat als pors. El tercer capítol de la tesis s'ha centrat en la preparació d'un material per a la lliberació controlada d'agents citotòxics en cèl¿lules canceroses en resposta a canvis en el potencia redox. De nou s'empren nanopartícules de sílice mesoporoses amb els pors carregats amb un colorant (safranina O) i la superfície externa funcionalitzada amb dos polietilenglicols (de diferent pes molecular) contenint enllaços disulfur. En presència de glutatió es produeix la reducció del enllaç disulfur amb la consegüent lliberació del colorant. Una volta confirmat el protocol d'obertura, es va estudiar la internalització i la lliberació d'un fluoròfor i d'un agent citotòxic en el model cel¿lular HeLa, realitzant ademés assajos de viabilitat. En el quart capítol de la tesis s'ha preparat i s'ha estudiat un nanodispositiu per a la lliberació controlada en cèl¿lules senescents, en un model murí de fibrosis pulmonar. El material es prepara emprant nanopartícules de sílice mesoporoses i un galactooligosacàrid anclat a la superfície externa del material. En presència de cèl¿lules senescents, que sobreexpresen el enzim ¿-galactosidasa, es produeix la hidròlisis del oligosacàrid amb el consegüent alliberament de la càrrega atrapada en els pors del suport (rodamina B). Després dels estudis in vitro, la capacitat del nanodispositiu d'acumular-se i lliberar la càrrega en teixits rics en cèl¿lules senecents es va evaluar in vivo. Amb este propòsit, ratolins amb fibrosis pulmonar induïda, patologia en la que s'ha descrit l'aparició de senescència en els teixits danyats, es van tractar amb el material sintetitzat i posteriorment van ser examinats per a comprovar la capacitat d'acumular-se i lliberar la seua càrrega (fluoròfor) en la zona dels pulmons afectada. En el quint capítol s'ha explorat el procés de comunicació química en cascada utilitzant tres tipus de nanopartícules mesoporoses de sílice carregades amb diferents missatgers i funcionalitzades amb tres portes moleculars diferents. Quan, sobre una suspensió de les tres nanopartícules, s'afegeix l'enzim capaç d'hidrolitzar la porta molecular que bloqueja els pors del primer tipus de nanopartícules (S1), es produeix la lliberació del missatger 1 des de S1. Este missatger és capaç d'induir l'obertura del segon tipus de nanopartícules (S2), les quals lliberen al medi el missatger 2. Per últim, el missatger 2 és capaç d'obrir la porta molecular del tercer tipus de nanopartícules (S3), que lliberen finalment la seua càrr
Giménez Morales, C. (2016). Design of new bio-gated nanodevices for advanced communication processes and targeted controlled release of therapeutic agents [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/62822
TESIS

Orientador: Antonio Wilson Sallum
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
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Resumo: O objetivo deste estudo foi avaliar o efeito da associação da administração local de nanoesferas contendo doxiciclina (DOX) com o debridamento periodontal no tratamento da periodontite crônica avançada. As nanoesferas foram preparadas pelo método da dupla emulsão (W/O/W), e caracterizadas quanto à morfologia através da microscopia eletrônica de varredura (MEV), e quanto à interação polímero (PLGA) e DOX através da espectroscopia infravermelha da transformada de Fourier (FTIR). A avaliação da liberação controlada de DOX foi feita através da cromatografia líquida de alta eficiência (HPLC), a partir do fluido gengival sulcular (GCF) coletado nos períodos: 2, 5, 7, 10, 15 e 20 dias após aplicação das nanoesferas. Foi realizado um ensaio clínico randomizado controlado duplo cego, incluindo 30 pacientes diagnosticados com periodontite crônica que apresentavam sete sítios com sangramento à sondagem e profundidade de sondagem (PS) ? 5 mm, sendo 2 dentes com PS ? 7 mm. Os pacientes foram aleatoriamente divididos em 2 grupos e receberam os seguintes tratamentos: debridamento periodontal por 45 minutos associado à administração local de nanoesferas contendo doxiciclina nos sítios com PS ? 5 mm (DB+DOX) ou debridamento periodontal por 45 minutos associado à aplicação de nanoesferas vazias (DB). Foram avaliados os seguintes parâmetros clínicos: Índice de Placa (IP), Sangramento à Sondagem (SS), Profundidade de Sondagem (PS) e Nível de Inserção Clínica (NIC), no baseline, 3 e 6 meses após a terapia. A avaliação microbiológica foi feita por meio da reação de cadeia de polimerase ¿ tempo real ("real time" - PCR) para detecção das bactérias: Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Aggregatibacter actinomycetemcomitans e Prevotella intermedia, provenientes do biofilme subgengival coletado no baseline, 1, 3 e 6 meses após o tratamento. Os resultados foram comparados por meio do teste de análise de variância com medidas repetidas, com nível de significância de 5%. Foram obtidas nanoesferas variando de 700 nm a 4 um. Através do FTIR observou-se boa interação da DOX com o PLGA, sem alterações das propriedades químicas de nenhum dos compostos. Após a aplicação das nanoesferas observou-se uma liberação de DOX constante no GCF até o vigésimo dia pós-tratamento, acima da concentração inibitória mínima. No grupo DB+DOX houve redução significativa da PS e ganho de inserção clínica nas bolsas profundas e moderadas em relação ao baseline e entre grupos. Observou-se redução significativa dos níveis bacterianos pós-tratamento, sendo o grupo DB+DOX mais eficaz em manter os níveis mais baixos após 6 meses do tratamento. Dentro das limitações deste trabalho, os resultados sugerem que as nanoesferas de PLGA são efetivas como sistema de liberação controlada local de DOX e quando associadas ao debridamento periodontal podem promover resultados superiores em relação à terapia mecânica isoladamente
Abstract: The aim of this study was to assess the effect of the association of local administration of nanospheres loading doxycycline (DOX) with the periodontal debridement treating advanced chronic periodontitis. Nanospheres were made by double-emulsion method (W/O/W) and characterized regarding morphology, by scaning eléctron microscopy (SEM); and drug/polymer interaction, by Fourier transform infrared spectroscopy (FTIR). The DOX controlled release was assessed by high performance liquid chromatography (HPLC) of gingival crevicular fluid (GCF) samples collected 2, 5, 7, 10, 15 and 20 days after treatment. It was performed randomized double-blinded clinical trial, with thirty patients diagnosed with chronic periodontitis presenting at least seven sites with bleeding on probing and probing depth (PD) ? 5 mm, and 2 sites with PD ? 7 mm. The patients were randomly allocated in two groups receiving interventions as followed: 45 minutes periodontal debridement + subgengival nanospheres loading DOX (DB+DOX); and 45 minutes periodontal debridement + subgengival void nanospheres (DB). Plaque index (IP), bleeding on probing (BP), probing depth (PD) and clinical attachment level (CAL) were evaluated on baseline, 3, and 6 months after therapy. Real-time polymerase chain reaction (real-time PCR) was used to quantify Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Aggregatibacter actinomycetemcomitans and Prevotella intermedia from subgingival biofilm samples collected on baseline, 1, 3 and 6 months after treatment. The results were compared by variance analyses test for repeated measures, with significance of 5%. Nanospheres varying from 700 nm to 4 um were obtained. There was a good interaction between DOX and PLGA, with no chemical properties alterations. After local administration of the nanospheres, it was observed constant DOX release in the GCF until 20th day post-treatment, with concentration above the minimum inhibitory concentration. DB+DOX group showed significant PD reduction and CAL gain in deep and moderates pockets comparing to baseline and between groups. It was observed significant reduction of bacteria levels along follow up period, and DB+DOX group was more eficiente in keeping lower levels of bacteria after 6 months from treatment. Within limitations of this study, the results can suggest that PLGA nanospheres are effective carriers for controlled release of DOX and when used adjunctively to periodontal debridement, improved results can be achieved compared to mechanical therapy alone
Doutorado
Periodontia
Doutor em Clínica Odontológica

Doctor of Philosophy
Department of Chemistry
Stefan Bossmann
A novel type of supramolecular aggregate, named "nanosponge" was synthesized through the interaction of novel supramolecular building blocks with trigonal geometry. The cholesterol-(K/D)[subscript n]DEVDGC)₃-trimaleimide unit consists of a trigonal maleimide linker to which homopeptides (either K or D) of variable lengths (n = 5, 10, 15, 20) and a consensus sequence for executioner caspases (DEVDGC) are added via Michael addition. Upon mixing in aqueous buffer, cholesterol-(K)[subscript n]DEVDGC)₃-trimaleimides, as well as a 1:1 mixture of cholesterol-(K/D)[subscript n]DEVDGC)₃-trimaleimides form stable nanosponges, whereas cholesterol-(D)[subscript n]DEVDGC)₃-trimaleimide is unable to form supramolecular aggregates by itself. The structure of the novel nanosponges was revealed through explicit solvent and then coarse-grained molecular dynamics (MD) simulations. The nanosponges are between 80nm and several micrometers in diameters and virtually non-toxic to monocyte/macrophage-like cells. Furthermore, the structure of novel binary nanosponges consisting of cholesterol-(K/D)[subscript n]DEVDGC)₃-trimaleimide units possessing a trigonal maleimide linker, to which either lysine (K)₂₀ or aspartic acid (D)₂₀ are tethered, has been elucidated by means of TEM. A high degree of agreement between these findings and structure predictions through explicit solvent and then coarse-grained molecular dynamics (MD) simulations has been found. Based on the nanosponges’ structure and dynamics, caspase-6 mediated release of the model drug 5(6)-carboxyfluorescein has been demonstrated. Moreover, the binary (DK20) nanosponges have been found virtually non-toxic in cultures of neural progenitor cells. Additionally, DK20 nanosponges were taken up efficiently by leucocytes (WBC) in peripheral blood within 3h of exposure. The percentage of live cells among the WBC was not significantly decreased by the DK20 nanosponges. Therefore, this novel material holds great promise for improved cell-mediated therapy. Two different nanosponges loaded with the anticancer agent perillyl alcohol (POH) were developed to test the suitability of nanosponges for cell-based cancer therapy. Drug-loaded nanoshuttles featuring trigonal supramolecular building blocks, type (D-POH)₁₀K₂₀ and (D-POH)₁₀R₂₀ were synthesized, purified, and characterized by Dynamic Light Scattering (DLS) and Atomic Force Microscopy (AFM). They were then tested in cell cultures of murine glioma cells (GL26) and murine neural progenitor cells (NPC). The two nanosponges exhibited significantly different biophysical properties (size distribution and zeta potentials). Consequently, different efficacies in killing GL26 and NPC were observed in both, serum free and serum containing culture media. The results from these experiments confirmed that type (D-POH)₁₀K₂₀ nanosponge is an excellent candidate for the cytotherapy of glioblastoma.

Implantable drug delivery is becoming an increasingly important field of research, providing great potential for a wide range of flexible and low cost solutions for localized treatment of chronically debilitating diseases. This dissertation presents work that encompasses several approaches for the remote triggering, powering, and control of micro drug delivery devices and systems, designed with remote-controllability, minimal power requirements, biocompatibility, and the potential for minimally invasive implantation in mind. The control mechanisms used rely on microtechnology, nanotechnology, and electromagnetic power transfer to magnetic nanoparticles and magnetic nanowires, for the heating and actuation of thermoresponsive Poly(N-isopropylacrylamide) hydrogels (PNIPAm) in the form of nanoparticles in membranes and stand-alone microdroplets, and actuation of flexible membranes for drug pumping. Thermoresponsive PNIPAm, in any form such as nanoparticles, microdroplets, or mezzo scale bulk material shapes, has the property of swelling with water in its hydrophilic state below a critical temperature. At higher temperatures, a sharp change occurs, the polymer network becomes hydrophilic, and the water molecules in the network is expelled, causing the overall material to shrink in size, while the released water or aqueous solution is left free to flow around or away from the material. When embedded in membrane matrices used as drug delivery gates, PNIPAm nanoparticles act as diffusion and flow blockers below the critical temperature. When PNIPAm surpasses the critical temperature, induced by heat from local magnetic iron oxide nanoparticles (exposed to a 62 mT, 450 kHz magnetic field), it shrinks in size and increases the drug flow through membrane pathways. The combination of this membrane design with osmotic pumping and methods for tailoring the drug release profile is reported. Simulation supports experimental results while describing interactions between the osmotic pump and the thermoresponsive membranes. A sensitivity analysis based on a fluidic circuit analogy gives insight into the contributions of the components of the device, in particular those of membranes affecting the displacement of fluid. PNIPAm microdroplets, spherical microparticles larger than the PNIPAm nanoparticles discussed above, are fabricated with embedded magnetic iron oxide nanoparticles or magnetic iron nanowires and pre-loaded with an aqueous drug. Upon magnetic heating, these microdroplets shrink in size and expel the drug. Magnetic nanowires have much lower power requirements when compared with widely-used iron oxide magnetic nanoparticles for triggering PNIPAm, due to their ability to generate losses via physical vibration within the microdroplets. A model is used to corroborate the experimentally observed low power (1 mT, 20 kHz magnetic field) required to induce PNIPAm microdroplet shrinkage. This model for nanowire loaded microdroplet design is compared with the well-established theory for power generation from magnetic iron oxide nanoparticles, and associated experiments (using a 72 mT, 600 kHz magnetic field) in order to confirm the validity of the calculated power generated by iron nanowires. The findings in this work offer several flexible options for the application of PNIPAm as a remotely triggerable drug delivery controller or carrier, using relatively simple fabrication methods, permitting several degrees of customization of the delivery rate or profile by adjusting the PNIPAm material, its magnetic content, and the applied magnetic field, all the while demonstrating the use of magnetic nanowires as a more efficient power transfer material when compared to traditionally used magnetic nanoparticles. The findings associated with the efficient triggering of PNIPAm microdroplets can be implemented in a more power-friendly design of magnetic, remotely triggered membranes which, although implemented in conjunction with osmotic pumps here, can be coupled with other pressure sources.
Applied Science, Faculty of
Engineering, School of (Okanagan)
Graduate

The targeted delivery of drugs is one of the most actively pursued goals in anti-HIV and anti-cancer chemotherapy. This project takes a proof-of-concept approach to the development of protein-based drug delivery systems - delivery systems that would package, target, and deliver cytotoxins to diseased cells. Primarily, this project explores the use of the potent anti-HN protein, cyanovirin-N (CV-N), to actively target and deliver cytotoxic natural products to HN-infected cells. This project also investigates the use of human serum albumin (HSA), a 66 kDa protein, as a macromolecular carrier to passively target and deliver cytotoxic natural products to cancerous cells. To facilitate release of the toxin within infected cells, an enzymatically-cleavable tetra peptide was incorporated in the conjugates. Maleimido-activated tetra peptide toxin constructs were prepared in readiness for selective reaction with proteins carrying thiol functionalities. Release of the toxin, norhomohalichondrin B, was demonstrated in vitro. Native CV -N conjugates were prepared by thiolation of the lysine ε-amino groups, and the subsequent reaction with maleimido-activated compounds. Reaction across all lysine residues was demonstrated. A singly-substituted tyrosinamide conjugate of CV-N was prepared. Two recombinantly produced mutant CV-N proteins allowed for the production of selectively modified, double- and single-norhomohalichondrin B conjugates of CV-N. The conjugates retained the anti-HN activity of the parent protein. Homohalichondrin B, doxorubicin, and tyrosinamide conjugates of HSA were prepared. The syntheses exploited the availability of a free thiolmoiety at cysteine-34 of HSA, and the specific and selective reaction of this thiol with the maleimido-activated tetra peptide derivatives. All toxin conjugates demonstrate excellent cell toxicity. Further research to investigate whether this is targeted toxicity is currently underway.

Drug delivery systems (DDS) with multiple functionalities such as environment-sensitive drug release mechanisms and visualization agents have motivated the biomedical community as well as materials chemists for more than a decade. This dissertation is concerned with the development of nanoparticles for multifunctional DDS  to tackle several crucial challenges in these complex systems, including polymeric nanospheres which respond to temperature change, superparamagnetic iron oxide nanoparticles/polymeric composite for magnetic resonance imaging contrast agents and drug carriers, immunoresponse of nanomaterials and injectable magnetic field sensitive ferrogels. The biocompatible and biodegradable polylactide (PLA) was employed as matrix materials for polymeric nanosphere-based DDS. The thermosensitive polymeric nanospheres have been constructed through a “modified double-emulsion method”. The inner shell containing the thermosensitive poly(N-isopropylacrylamide) (PNIPAAm) undergoes a “hydrophilic-to-hydrophobic” phase transition around the human body temperature. The sensitivity of the polymer to the temperature can facilitate drug release at an elevated temperature upon administration. In addition, gold nanoparticles were assembled on the dual-shell structure to form a layer of gold shell. The cell viability was found to be enhanced due to the gold layer. The immunoresponse of the gold nanoparticles has been considered even if no acute cytotoxicity was observed. Imaging is another functionality of multifunctional DDS. This work focuses on magnetic resonance imaging (MRI) and involves synthesis and surface modification of superparamagnetic iron oxide nanoparticles (SPIONs) for contrast agents. The SPIONs have been prepared through a high temperature decomposition method. Surface modification was carried out in different ways. Poly(L,L-lactide) (PLLA) was grafted on SPIONs through surface-initiated ring-opening polymerization. The hydrophobic model drug indomethacin was loaded in the PLLA layer of the composite particles. For biomedical applications, it is essential to modify the hydrophobic particles so that they can be dispersed in physiological solutions. A series of protocols including using small charged molecules and amphiphilic polymers has been established. Pluronic F127 (PF127), a triblock copolymer was applied as a phase transfer reagent. Most interestingly, PF127@SPIONs show remarkable efficacy as T2 contrast agents. The PF127@SPIONs have been successfully applied to image the cochlea in a rat model. As another phase transfer reagent, poly(maleic anhydride-alt-octadecene)-graft-PNIPAAm (PMAO-graft-PNIPAAm) was created for surface modification of SPIONs. This new copolymer provides the modified SPIONs with thermosensitivity together with water-dispersibility. As another form of DDS, ferrogel made of PF127 copolymer and SPIONs was developed. Gelation process depends on the temperature of the SPIONs/PF127 mixture. This property makes it possible to use the ferrogel as an injectable drug carrier. Unlike other ferrogels based on crosslinked polymeric network, the PF127 ferrogel can entrap and release hydrophobic drugs. Application of an external magnetic field is found to enhance the drug release rate. This property can find application in externally stimulated local drug release applications.
QC20100722

Nanoparticulate delivery systems have been widely used in recent decades, available in a wide variety of structures, for targeted drug delivery. They provide controlled and prolonged release for drugs, peptides and biopharmaceuticals. Ceramic nanoparticles are one of the various nanocarriers, which have been employed in local targeted delivery, most commonly in the area of orthopaedic drug delivery to enhance treatment therapies. This thesis therefore focused on the development of aquasomes, a ceramic nanoparticulate carrier system, for the delivery of proteins, growth factors and antibiotics for its potential application in bone regeneration in fracture healing. The suitability of non-aqueous silicone elastomer gels (NASEGs) as a topical/transdermal delivery system for proteins as well as protein-loaded aquasomes was also investigated. Through process optimisation, a suitable lyophilisation method was developed and used for the preparation of bioactive aquasome formulations of growth factors, bone morphogenetic protein (BMP-2), vascular endothelial growth factor (VEGF-121), and antibiotic, gentamicin. Physical characterisation of aquasomes using zeta potential and optimisation of preliminary aquasome formulations were optimised by utilising smaller nanocore sizes. In addition, scanning electron microscopy (SEM), confocal microscopy analysis and entrapment efficiency studies were performed to ascertain the drug loading efficiency of the different aquasome formulations. BMP-2 loading aquasomes exhibited an entrapment efficiency of 98.9% Protein loading on aquasomes yielded a higher negative zeta potential in comparison to blank nanocores. Confocal microscopy images elucidated the behaviour of nanocore particles showing agglomeration of nanocores and the presence of fluorescent drug adsorbed onto nanocores. The bioactivity of the aquasome formulations were analysed via in vitro cell culture model assays and microbiological assays. BMP-2-loaded aquasomes were investigated for enhanced osteogenic proliferation and differentiation effects on osteoblast-like cells, MG63 cells. The enhanced osteogenic effect of HUVECs in co-culture with these cells was also examined. In addition, the committed differentiation of ATMSCs into osteoblasts induced by their exposure to BMP-2 -loaded aquasomes was also investigated. Results exhibited the enhanced osteogenic differentiation effect, analysed by alkaline phosphatase (ALP) secretion (a major biochemical marker of osteoblastic differentiation) from MG63 cells was dependent on the protein loading onto the aquasome formulation. However, differentiation of ATMSCs cultured in osteogenic medium was significantly higher than ATMSCs exposed to BMP-2 or VEGF-121 treatments. Gentamicin-loaded aquasomes were investigated for their antimicrobial activity against Staphylococcus aureus, a major pathogen popularly implicated in cases of osteomyelitis. Results showed that gentamicin released from aquasomes exhibited excellent bactericidal activity against bacterial cultures without any reproduction of bacteria in 24 hours. In conclusion, the aquasome formulations were able to offer controlled release of bioactive antimicrobials and growth factors over a prolonged duration. The amount of bio-actives released was dependent on the loading of the bio-actives in the fabrication process of aquasome formulations. However, minute (ng/μg) amounts of adsorbed growth factor/drug were observed in comparison to the loading (high ng/mg) within the duration of study. It can be inferred these aquasomes can be employed in the sustained local and targeted delivery of antimicrobials and growth factors in orthopaedic treatments for enhanced fracture healing. However, the loading of bio-actives onto aquasome formulations may need to be optimised to increase the amount of bio-actives released to elicit more pronounced pharmacological effects.

This thesis describes the novel synthesis of eight polyamine-nitrogen mustard conjugates and two polyamine-nitroxide conjugates. The structure-activity relationship of these compounds with DNA has been investigated. The approach started with the regioselective BOC protection of commercially available norspermidine, spermidine and spermine plus the total synthesis of protected polyamines e.g. homospermidine and spermine. The nitrogen mustards chlorambucil and melphalan were conjugated to the polyamines at primary and secondary nitrogens via a variable length amide linkage to give a structural range of differentially charged polyamine-drug conjugates. The spin label 3-carboxy-proxyl was conjugated to a primary and secondary nitrogen of spermine via an amide linkage to give two novel spermine-spin labelled adducts. Electron paramagnetic resonance spin exchange experiments in the presence of DNA gave an indication of translational motion of spermine on the DNA. The DNA cross-linking of the polyamine-nitrogen mustards identified that: (i) spacing between positive charges does not significantly affect the cross-linking efficiency, (ii) increasing the positive charge of the polyamine increases the cross-linking ability of the conjugates (reflecting the trend in binding ability of charged polyamines) and (iii) primary amino polyamine-drug conjugates are more efficient cross-linkers than the corresponding secondary amino conjugates. The polyamine-nitrogen mustard conjugates also showed the same sequence selectivity as the parent drugs i.e. chlorambucil and melphalan. The N7 position in the major groove of DNA is alkylated. Runs of contiguous guanines provide sites of highest alkylation for chlorambucil and the polyamine-drug conjugates. The results imply that the initial site of alkylation is not dictated by the poly amine moiety binding to specific sites on DNA.

Polyanhydrides are useful biodegradable vehicles for controlled drug delivery. In aqueous media the breaking of the anhydride bonds resulting in gradually polymer fragments collapse and release drugs in a controlled manner. In this study, two new biodegradable polyanhydrides copolymers were synthesised using a melt-polycondensation method. The first is poly (bis (p-carboxyphenoxy)-2-butene-co-sebacic acid) (CP2B: SA), which has double bonds along the polymer backbone. The second is crosslinked poly (glutamic acid-sebacic acid-co-sebacic acid) (GluSA: SA), where the conjugated unit of glutamic acid with sebacic acid (glutamic acid-SA) acted as a crosslinking fragment in producing the crosslinking polymer. The two polymers were applied to preparation of microspheres with bovine serum albumin (BSA) as a model protein, using both double emulsion solvent evaporation and spray drying methods. The characterisation of the microspheres, morphology, particle size, and drug loading, was studied. The in vitro hydrolytic degradation of polymers and blank microspheres was monitored using IR, GPC, and DSC. In vitro drug release behaviour was also studied. Though the studies showed cleavages of anhydride bonds occurred rapidly (<5 days), bulks of the polymer microspheres could be observed after a few weeks to a month; and only around 10-35% of the protein was detectable in a four-week period in vitro. We found the pH of the medium exerts a large impact on the release of the protein from the microspheres. The higher the pH, the faster the release. Therefore the release of the protein from the polyanhydride microspheres was pH-sensitive due mainly to the dissolution of monomers from the microspheres.

Homing is the process that stem cells move to their own stem cell niches under the influence of chemokines like stromal-derived factor-1&alpha
(SDF-1&alpha
) upon bone marrow transplantation (BMT). There is a need for increasing homing efficiency after BMT since only 10-15% of the transplanted cells can home to their own niches and a limited amount of donor marrow can be transplanted. In this study, we aimed to develop and characterize bone marrow targeted liposomal SDF-1&alpha
delivery system prepared by extrusion method. Alendronate conjugation was chosen to target the liposomes to bone marrow microenvironment, particularly the endosteal niche. Optimization studies were conducted with the model protein (

Delivery across skin offers many advantages compared to oral or parenteral routes e.g. non-invasive, avoiding first-past metabolism, improved bioavailability and reduction of systemic side effects. Microneedle (MN) are minimally-invasive devices that painlessly by-pass the skin's stratum corneum, which is the principal barrier to topically-applied drugs. Polymeric MN delivery systems were designed and evaluated to transdermally deliver two model drugs, the small water soluble drug ibuprofen sodium and the large protein ovalbumin (OVA). A range of hydrogel forming materials for MN production was evaluated to identify the most suitable super swelling hydrogel MN array that are hard in the dry state but, upon insertion into skin, rapidly take up interstitial fluid. The MN themselves contain no drug, but instead drug are loaded into lyophilized patches. Novel super swelling hydrogel forming MN arrays were fabricated from aqueous blends containing 20% w/w poly(methyl vinyl ether co maleic acid) (Gantrez® S97), 7.5% w/w poly(ethylene glycol) (PEG) and 3% sodium carbonate (Na2C03). In addition, dissolving MN arrays loaded with a high dose of non-potent therapeutic drug were fabricated from aqueous blends of 70% w/w Gantrez® AN139 (PH 7) and 30% ibuprofen sodium. Successful drug delivery was achieved in this research work using novel polymeric MN, super swelling hydrogel MN and dissolving MN. The in vitro studies has been shown first ever example of polymeric MN being loaded with a NSAIDs. The novel concept of super swelling hydrogel MN integrated with lyophilized patches loaded with ovalbumin was evaluated. They enabled the sustained delivery of the ibuprofen sodium and ovalbumin both in vitro and in vivo. Gamma sterilization can be done without compromising polymeric MN properties. Finally, hydrogel forming MN arrays can be successfully and reproducibly applied by human volunteers given appropriate instruction so the use of MN applicator devices may not be necessary, thus possibly enhancing patient compliance.

Development of liposome formulation of an amphiphilic anticancer peptide using the ANTS/DPX leakage assay. The effects of lipid composition on the liposomes' resistance to an amphiphilic cyclic peptide c[KS.S.S.KWL W] were studied by the ANTS/DPX leakage assay. One or more unsaturated acyl chains in the phospholipids, small phospholipid headgroup size, the presence of cholesterol, and the presence of PEG-lipid were demonstrated as critical parameters to stabilize the liposome membrane. A liposome formulation of the peptide comprising POPE/POPC/cholesterol/C16 mPEG 2000 ceramide (20.8:31.2:40:8, mol%) was thereby developed with a peptide-encapsulation efficiency of 47.8%. The liposomal cyclic peptide exhibited dose-dependent toxicity to MCF7 human breast cancer cells and stability under incubation. Design, construction and in vitro characterization of a hydrazone-based convertible liposomal system for anticancer drug delivery. A novel PEG-lipid, PEG2ooo-Hz-DHG, with an acid-labile hydrazone linker between the PEG2ooo head group and the lipidic DHG moiety was synthesized. PEG2000-Hz-DHG was relatively stable at normal physiological pH 7.4, but hydrolyzed more quickly at tumor interstitium pH 6.5-7.0 and endosomal/lysosomal pH 5.0. A novel pH-sensitive "Convertible Liposome System" (CLS) was constructed comprising PEG2ooo-Hz-DHG, positively charged lipid DOTAP, and the zwitterionic phospholipid POPC (8:15:77, mol%). CLS converted from neutrally charged "stealth" liposome to positively charged liposome at tumor interstitual pH owing to the hydrolysis ofPEG2ooo-Hz-DHG. The doxorubicin-encapsulated CLS that had been pre-incubated at pH 6.5 for 30 h exhibited more intensive binding and higher toxicity to Bl6-Fl0 murine melanoma and MDA-MB-435S human breast cancer cells than doxorubicin encapsulated in pH-insensitive stealth liposome.

Delivery of drugs to the posterior segment of the eye is notoriously difficult and unfortunately many chronic conditions of the posterior segment often lead to sight-loss if not treated effectively. Current methods of delivery such as topical drops result in poor bioavailability at the back of the eye, while the blood brain retina imposes restrictions on the entry on drugs into the eye delivered by the systemic system. The gold-standard method for delivery of therapeutic concentrations of drugs is intravitreal delivery, which involves an injection into the vitreous cavity. Although this provides therapeutic levels of drugs, numerous injections are required to maintain these concentrations, and the frequency of injection can cause various adverse effects such as retinal detachment, vitreous haemorrhage and endophthalmitis. The present study investigates the potential use of solvent-induced in situ forming implants (ISFI) as a method of delivering drugs in a prolonged manner to the posterior segment of the eye. These systems are composed of a water-insoluble polymer dissolved in an organic solvent. Their low viscosity allows for easy administration through small-bore needles (e.g. 27 gauge) and on contact with an aqueous environment, such as the vitreous humour, phase inversion through solvent exchange takes place resulting in a biodegradable polymeric implant that can release drugs for an extended period. . As another method to improve posterior drug delivery in a minimally-invasive manner, microneedles (MN) were used to inject small amounts of ISFI formulation into sclera. Drug release and permeation stUdies across sclera indicated that the use of MN did indeed improve scleral permeation, with potential to allow posterior drug delivery from an intrascleral depot. From investigations carried out in the present study, ISFI show promise in transforming drug delivery to the eye and therefore possibly preventing the loss of sight in numerous individuals.

In this thesis two different ways to improve platinum-based chemotherapy were investigated. The first was through the use of a new slow release clay-based drug delivery vehicle and the second through the design and synthesis of novel dinuclear platinum complexes. For the clay-based drug delivery research, the platinum anticancer complex [(1,10-phenanthroline)(1S,2S-diaminocyclohexane)platinum(II)] chloride, PHENSS, was loaded into montmorillonite (MMT) clay. The PHENSS was found to be incompletely burst released from the MMT. The MMT also had a negative effect on the in vitro cytotoxicity of PHENSS in the human breast cancer cell lines MCF-7 and MDA-MB-231. Overall the results demonstrate that MMT is not a suitable slow release vehicle for PHENSS. For the dinuclear platinum complex synthesis research, new bispyridine-based bridging ligands were synthesised using an amide coupling reaction. The bridging ligands were then reacted with transplatin to yield the dinuclear platinum complexes. The platinum complexes have potential application as anticancer agents and the synthetic method can be modified to produce other multinuclear complexes.

The therapeutic effect of pulmonary drug delivery systems is limited by its rapid clearance from the lungs by robust clearance mechanisms. By controlling the release of drugs, the therapeutic effect of pulmonary drug delivery systems, as well as patient convenience and compliance could be improved by reducing the number of times drugs need to be administered. In this study, two controlled pulmonary drug delivery systems for drugs of different solubilities were investigated and they were characterised for their viability as effective controlled release pulmonary drug delivery systems, particularly in areas of aerosol performance and dissolution profile. A hybrid protein-polymer controlled release pulmonary drug delivery system was developed to sustain the release of a water-soluble anti-asthma drug, cromolyn sodium (CS). Two excipients with complementary characteristics – a protein, bovine serum albumin, and a polymer, polyvinyl alcohol – were formulated together with CS via co-spray drying, with varying protein-polymer ratios and drug loadings. The hybrid particles showed promise in combining the positive attributes of each excipient, with respirable particles shown to sustain the release of CS with a fine particle fraction of 30%. Combining the two excipients was complex, with further optimisation of the hybrid formulations possible. A commercially available polymer, Soluplus® was spray-dried with a poorly-water soluble corticosteroid, beclomethasone dipropionate (BDP). The resultant respirable powders were shown to have potential for use as a controlled release pulmonary drug delivery system with up to 7-fold improvement in the amount of BDP released compared to spray-dried BDP. The spray-dried BDP-Soluplus® powders were found to be amorphous, and physically stable against re-crystallisation for up to 9 months at accelerated stress test conditions with drug loadings of up to 15 % (w/w). Although it provided a platform to compare between formulations, the USP 4 flow-through cell dissolution apparatus was found to be inadequate to accurately study the dissolution profiles of the pulmonary drug delivery systems due to the formation of a gel in the apparatus. Preliminary work on the use of a novel technique to predict the crystallisation of amorphous formulations with terahertz time-domain spectroscopy was also conducted. The system confirmed the re-crystallisation tendencies of several hybrid CS/BSA/PVA formulations. Modification to the experimental setup to probe the formulations at different relative humidities instead of temperatures could yield improved results.

During this doctoral research work new potential drug delivery vehicles for targeted treatment of cancers were developed. For this purpose, both soft and hard materials were subject of study. Firstly, the synthesis, the characterization and the biological evaluation of monomeric â-cyclodextrins functionalized with folic acid (FA) were the focus of this research. In particular, four new conjugates (CyD-FAs), both 3- and 6-functionalized â-CyDs (â-CyD3 and â-CyD6) linked to the á- or ã-carboxylic group of the FA were synthesized, isolated and fully characterized. Furthermore, the ability of these compounds to include the anticancer drug LA-12 and to deliver it selectively to FR (+) tumor cell lines was investigated. Since the promising results obtained with these CyD-FA conjugates as carriers for LA-12, polymeric nanoparticles based on cross-linked cyclodextrins were designed for drug delivery purposes. These systems, offer the advantages of CyD-type complexation in a synergistic way, resulting more effective than the parent CyDs. In particular, CyD-based polymers and oligomers were synthesized, functionalized with FA and tested as delivery systems towards different hydrophobic anticancer or anti-inflammatory agents. Furthermore, for selected systems, the binding constants of the formed inclusion complexes were determined as well. Concerning hard materials, mesoporous silica nanoparticles were investigated. A new disc-shaped mesoporous material, the nanodiscs (NDs), was synthesized, isolated and fully characterized. This material was firstly used for the preparation of self-assembled monolayers (SAM), to be employed in targeted cancer cell adhesion and in-situ drug delivery. For this purpose, the NDs-monolayers were functionalized with FA as targeting moiety. Thanks to their large surface area and the possibility of high density of superficial functionalization with bioactive molecules, these systems resulted effective in binding cancer cells even upon short contact times. Moreover, exploiting the porosity of the synthesized particles, the intracellular release of small hydrophobic molecules pre-loaded in the channels of the NDs were achieved. Secondly, preliminary biological experiments carried out to test the cellular uptake of NDs, and the drug-carrier ability were performed. Finally, in the attempt to increase the biodegradability of these interesting structures, disulfide-doped mesoporous silica nanodiscs (ss-NDs) were also prepared. Full characterization and preliminary biological assays of these hybrid materials was also performed, and their degradation in redox conditions investigated. This novel material, taking advantage of bio-redox reactions, undergoes a controlled disintegration process in presence of reducing agents (i.e. glutathione), displaying an improved drug delivery action.

The blood brain barrier (BBB) poses a significant hurdle to brain drug delivery. However, the location of the olfactory mucosa, within the nasal cavity, is a viable target site for direct nose-to-brain (N2B) delivery, thereby bypassing the BBB. To exploit this target site innovative nasal formulations are required for targeting and increasing residency within the olfactory mucosa. We developed and characterised three formulation systems for N2B delivery, (i) thermoresponsive mucoadhesion nasal gels sprays; (ii) mesoporous silica nanoparticles and (iii) nasal pMDI devices. We developed an optimal mucoadhesive formulation system incorporating amantadine as a model, water-soluble anti-Parkinson’s drug using carboxymethy cellulose and chitosan as mucoadhesives. Formulations demonstrated droplet sizes of < 130mm and stability over 8-weeks when stored at refrigeration conditions with no significant cellular toxicity against olfactory bulb (OBGF400) and nasal epithelial (RPMI 2650) cells. Mesoporous silica nanoparticles (MSNP) were prepared (~220nm) and demonstrated cellular uptake into OBGF400 within 2-hours of incubation with minimal toxicity. MSNP were loaded with two novel phytochemicals known to possess CNS activity, curcumin and chrysin, with loading efficiencies of ~12% confirmed through TGA, DSC and HPLC-UV analysis. Furthermore, a pH dependant release profile was identified with curcumin with greater release at nasal cavity pH 5.5 compared to pH 7.4. Furthermore, successful incorporation of MSNP into nasal gels was demonstrated through rheological studies with a decrease in Tsol-gel. A pilot study was conducted to assess the feasibility of modified existing pulmonary pMDI to deliver diazepam intranasally, targeting the olfactory mucosa. Diazepam was formulated with HFA134a and using ethanol as a co-solvent, and demonstrated stability in formulation over 3 months. Deposition studies within a nasal cast model demonstrated 5-6% deposition onto the olfactory mucosa under optimal administration conditions in the absence of any nozzle attachments. Our studies have provided a basis for the development to innovative intranasal formulation systems potentially capable of targeting the olfactory mucosa for both water soluble and poorly soluble drugs.

Micro/macroporous matrices comprising a continuous phase of poly([epsilon]-caprolactone) . (PCL) and a dispersed phase of water soluble particles (lactose and gelatin) with defined size range (45-90, 90-125 and l25-250[mu]m) were produced by rapid cooling solutions of PCL in acetone followed by solvent extraction from the hardened material. This novel approach enables high loading (29-44% w/w) of particles (lactose and gelatin) to be achieved in PCL matrices by suspension of particulates in the PCL solution prior to casting. Highly efficient protein release (90%) was obtained over time periods of 3 days to 3 weeks by variation of particle loading and particle size range. The good particle distribution throughout the matrix and efficient extraction of the water-soluble phase allows formation of a macroporous structure with defined pore architecture by incorporation of particles of a specific shape and size range. SEM analysis revealed the porous surface morphology. Micro computed tomography (micro-CT) and image analysis enabled visualization of the internal 3-D pore structure, quantification of the frequency distribution of equivalent pore diameter and porosity (%) in peL matrices. Micro/macroporous PCL tubes exhibited a burst strength of 125 to l45MPa under hydrostatic loading at 37[degree]C and good recovery of tube diameter following short-duration flow rates of 1000 ml/min under continuous increasing and pulsatile conditions. Sustained release of incorporated enzymes (lysozyme, collagenase and catalase) occurred over 11 days from the PCL matrices, with retained activity dependent on the particular enzyme used (collagenase 100% at 11 days, lysozyme 75-80% at 11 days, catalase 10-20 % at 5 days). Swiss3T3 fibroblasts exhibited strong attachment and successful colonization of the surface. of PCL matrices over 8 to 15 days in cell culture. These findings demonstrate the potential of micro/macroporous PCL matrices for scaffold production in tissue engineering and for controlling drug delivery.

Polymers are becoming preferred materials in biomedical applications because of their vast diversity of properties, functionalities and applications. Properties as mechanical strength, stability against degradation, biocompatibility and biodegradability, among others, have been attractive for different medical applications. One of the most interesting applications of these materials is drug delivery systems. Biodegradable polymers and copolymers are the preferred materials for the manufacture of a variety of devices for temporal applications in medicine and pharmacology; these biodegradable polymers can be chemically synthesized or biologically produced. Biotechnological polymers have attracted much attention because two main advantages; first, they are produced from renewable resources; and second, as they are biologically produced they are biocompatible, biodegradable and bioresorbable materials. Thus, modification of biotechnological polymers to obtain specific properties or functionalities is a good strategy for the development of promising biomedical materials. In this Thesis the water soluble biotechnological polymer poly(ß,L-malic acid) (PMLA) was modified to change its hydrophilic character to produce non water-soluble polymers capable of forming particulate systems for drug encapsulation and controlled release. PMLA is a polyester-3 with a pendant carboxylic group; it is biocompatible, biodegradable and bioresorbable. The carboxylic side group can be substituted in order to modify the properties of the polymer. The polymer as polyelectrolyte, is also water-soluble. Different strategies were used for polymer derivatization: direct esterification and amidation through the activation of the carboxylic side groups with carbodiimides; ionic complex formation with a cationic drug (Doxorubicin); and esterification with aliphatic long chains by a two step method employing thiol-ene click reactions. Obtained PMLA derivatives resulted in hydrophobic or amphiphilic polymers, which were appropriated for nanoparticle formation, either by emulsion solvent evaporation or by precipitation dialysis techniques. Derivatives physicochemical characterization was made by 1H and 13C nuclear magnetic resonance (NMR) spectroscopy, gel permeation chromatography (GPC) and differential scanning calorimetry. Hydrolytic degradation was followed by GPC and 1H NMR, while particles were observed by scanning electron microscopy and their size and surface charge characterized by dynamic light scattering and ζ-potential measurement. Assays of drug encapsulation and release were also performed and cytotoxicity tests were done on cancer cell lines. Nanoparticles (100-300 nm aprox.) were obtained from all PMLA derivatives, except for the ionic complex which formed microparticles. Nanoparticles showed potential as drug delivery systems since they were able to encapsulate the anticancer drugs Temozolomide and Doxorubicin, as well as the model drugs Theophylline and Carbamazepine. Drug release was assessed under physiological conditions; the release rate was found to depend on encapsulation method, drug and polymer derivative. Hydrolytic degradation assays showed that free malic acid and the organic compound derived from the reagent used for modification were the last products of aqueous degradation of PMLA derivatives. Cytotoxicity tests demonstrated the low toxicity of the synthesized derivatives. Results generated in this Thesis suggest that the biotechnological polymer PMLA is a material of interest as a platform for the design and development of biodegradable drug delivery systems with potential in the therapy of diseases considered today challenging for pharmacologic treatment.

This study evolved to its last form primarily around the development of a hybrid material is the core of the work. This hybrid material is then further explored for two different applications which are catalysis and drug delivery. A nanoassembly was established around a mesoporous silica support. SBA-15 was picked as this support among the other mesoporous silica dueto its well-defined pore structure and accessible pore volume. The silica framework was doped with Zr-atoms and the pores partly infiltrated with Cu nanoparticles resulting in a hybrid material with tunable properties. SBA-15 was synthesized by a sol-gel method where a micellar solution was employed as a template for the silica framework. To achieve the doped version, a Zr precursor was added to the synthesis solution. The effects of different synthesis conditions on the final material were investigated. lt was observed that changes in these synthesis conditions yielded different particle morphology, pore size, and specific surface area. The infiltration method is based on functionalizing the (Zr-) SBA-15 support surfaces before the Cu ion attachment whereas EIWI is based on slow evaporation of the liquid from the (Zr-)SBA-15 - Cu aqueous suspension. Both methods are designed to yield preferential growth of Cu NPs in the pores with a diameter smaller than 1O nm and in oxidized form. However, depending on the infiltration method used different chemical states of the final material is achieved, i.e. Zr content and porous network properties are different. Cu-Zr-SBA-15 nanoassembl ies were used for the catalytic conversion of C02 into valuable fuels such as methanol and dimethyl ether (DME). The effect of different chemical states of the catalyst was investigated. lt was found that the Si precursor had a considerable impact on the overall performance of the catalyst whereas the Cu loading method (lnf or EIWI) changed the catalytic selectivity between DME and methanol. The activity of the catalyst was further investigated in a time-evolution study where the accumulation of each product in the gas phase and the molecular groups attached to the catalyst surface were recorded over time. Accordingly, thermodynamic equilibrium was achieved on the 14th day of the reaction under 250ºC and 33 bar. The resulting total C02 conversion was 24%, which is the thermodynamically highest possible conversion, according to theoretical calculations. lt was also concluded from the experimental results that, DME is formed by a combination of two methoxy surface groups . Additionally, the formation of DME also boosts the total C02 conversion to fuels, which otherwise is limited to 9.5%. The design of Cu-Zr-SBA-15 was also investigated for drug delivery applications, dueto its potential as a biomaterial, e.g. , a filler in dental composites, and the antibacterial properties of Cu. Also, the bioactivity of Si02 and Zr02 was considered to be an advantage . With this aim, Cu infiltrated Zr doped SBA-15 material was prepared by using TEOSas the silica precursor and the lnf-method to grow Cu NPs. The performance of the final material as a drug delivery vehicle was tested by an in-vitro delivery study with chlorhexidine digluconate. The nanoassemblies show a drug loading capacity of 25-40% [mg drug 1 mg (drug+carrier)] . The drug release was determined to be composed of two steps. The presence of Zr and Cu limits the burst release and beneficially slows down the drug release process. The effect of pore properties of SBA-15 was explored in a study where the antibiotic doxycycline hyclate was loaded in SBA-15 materials with different pore sizes. lt was observed that the pore size is directly proportional to the drug loading capacity [mg drug 1 mg (drug+carrier)] and the released drug % (the released drug amounUtotal amount of loaded drug). The release profile was fast, dueto its weak interactions with the SBA-15 and smaller size molecule compared to chlorhexidine digluconate.
Los sistemas de materiales híbridos poseen propiedades multifuncionales. En este trabajo se desarrolló un nanoensamblaje alrededor de un soporte de sílice mesoporoso. Como soporte se seleccionó SBA-15 debido a su estructura de poro bien definida y volumen de poro accesible. La matriz de sílice fue dopada con átomos de Zr y los poros se infiltraron parcialmente con nanopartículas de Cu dando como resultado un material híbrido con propiedades ajustables . La síntesis de SBA-15 se realizó mediante un método de sol-gel en el que se empleó una solución micelar como plantilla para el sílice. Para lograr la versión dopada, se añadió un precursor de Zr a la solución de síntesis. Se investigaron los efectos de diferentes condiciones de síntesis, como el catalizador así como la fuente de Si en las características del material final. Los cambios en estas condiciones de. síntesis dieron lugar a partículas con distinta morfología, tamaño de poro (11-15 nm) y área superficial específica (400-700 m2/g). Las nanopartículas de Cu (NP) se hicieron crecer en el sustrato (Zr-) SBA-15 usando los métodos de infiltración (lnf) o de impregnación húmeda inducida por evaporación (EIWI).Dependiendo del método de infiltración utilizado, se logran diferentes propieddes químicas del material final, es decir, el contenido de Zr y las propiedades de red porosa son diferentes. Los nanoensamblajes de Cu-Zr-SBA-15 producidos bajo diversas condiciones de síntesis se usaron para la conversión catalítica de C02 en combustibles valiosos tales como metanol y dimetil éter (DME). El precursor de Si (TEOS o SMS) tuvo un impacto considerable en el rendimiento global del catalizador mientras que el método de carga de Cu (lnf o EIWI) cambió la selectividad catalítica entre DME y metanol. Por otra parte, la actividad del catalizador se investigó evaluando la acumulación de cada producto en la fase gaseosa y los grupos moleculares unidos a la superficie del catalizador a lo largo del tiempo. Se llegó al equilibrio termodinámico en el día 14 de la reacción a 250 ºC y 33 bar. La conversión total resultante de C02 fue del 24%, que es la conversión termodinámicamente más alta posible, según los cálculos teóricos . El material híbrido sintetizado Cu-Zr-SBA-15 también se investigó para aplicaciones de administración de fármacos, debido a su potencial como material de relleno en compuestos dentales y las propiedades antibacterianas del Cu. Por otra parte, la bioactividad de SiO2 y ZrO2 podría ser ventajosa para esta aplicación. El rendimiento del material final como vehículo de administración de fármacos se probó mediante un estudio de liberación in vitro con digluconato de clorhexidina . Los materiales desarrollados muestran una elevada capacidad de carga de fármaco (25-40%). Los perfiles de liberación del fármaco muestran dos etapas: una primera etapa de liberación rápida de las moléculas del fármaco unidas con interacciones más débiles al sustrato mesoporoso, seguida por la difusión de las moléculas del fármaco que están unidas a la superficie del portador. La presencia de Zr y Cu limita la liberación inicial y reduce la velocidad de liberación del fármaco . En otro estudio se evaluó el efecto del tamaño de poro de SBA-15 en la liberación del antibiótico hiclato de doxiciclina. Se observó que el tamaño de poro es directamente proporcional a la capacidad de carga de fármaco, el porcentaje y la cantidad de fármaco liberado . En resumen, este trabajo demuestra el carácter multifuncional de una nanomatriz diseñada a medida que proporciona información valiosa para dos aplicaciones en catálisis y liberación de fármaco.
Hybridmaterial består av minst två komponenter, vilket ger dem mångfacetterade egenskaper. Detta har gjort att denna typ av material attraktiva sedan länge. Det är dock inte enkelt att tillverka dessa materialsystem. Ett enkelt och effektivt tillvägagångssätt behövs för att tillvara ta de önskade egenskaperna hos varje komponent och få dem att samverka. Denna avhandling bygger huvudsakligen på utvecklingen av ett hybridmaterial.Ett hybridmaterial med en sammansättning bestämd på nanonivå, tillverkades med mesoporös kiseldioxid, SBA-15, som stomme. SBA-15 valdes framför andra typer av mesoporös kiseldioxid på grund av dess väldefinierade porstruktur och stora, tillgängliga porvolym. Kiseldioxiden dopades med zirkoniumatomer och porerna fylldes delvis med kopparnanopartiklar, vilket resulterade i ett hybridmaterial med egenskaper som kunde varieras. SBA-15 tillverkades via en våtkemisk metod där en micellösning används som mall för kiseldioxidens struktur. Vid dopningen tillsätts en zirkoniumkälla till synteslösningen. Effekterna av olika tillverkningsparametrar, till exempel salter med katalytiska egenskaper (salter med F- eller Cl-), olika kiselkällor (tetraetyl ortosilikat eller natriummetasilikat), på materialens egenskaper studerades. Variationer av dessa parametrar ger material med olika form, porstorlekar (11 – 15 nm) och specifik yta (400 – 700 m2/g). Kopparnanopartiklar växtes i (Zr-)SBA-15-stommarna med två metoder: infiltration (Inf) eller indunstningsinducerad våtimpregnering (EIWI). Inf baseras på funktionalisering av (Zr-)SBA-15-stommen innan kopparjoner fick reagera med ytan. EIWI bygger på en blandning av (Zr-)SBA-15 och kopparsalt i en lösning där vätskan långsamt får avdunsta. Båda metoderna är designade för framställning av oxiderade kopparnanopartiklar, mindre än 10 nm i diameter, som ska växa i stommens porer. Dock påverkar infiltrationsmetoden den kemiska sammansättningen hos det slutliga materialet då Zr-koncentrationen och porositeten i stommen ändras. Cu-Zr-SBA-15-sammansättningar, tillverkade med varierande syntesparametrar, användes som katalysatorer för omvandling av CO2 till bränslen såsom metanol och dimetyleter (DME). Resultaten visar att valet av kiselkälla har en stor inverkan på katalysatorns prestanda, samt att metoden för att introducera koppar ändrar den katalytiska selektiviteten mellan DME och metanol. Katalysatorns aktivitet undersöktes även över tid. Ackumuleringen av varje produkt, både i gasfas och på katalysatorns yta, registrerades över tid. Termodynamisk jämvikt nåddes efter att reaktionen fortgått i fjorton dagar vid 250 °C och 33 bar. Den totala CO2-omvandlingen var 24 %, vilket, enligt teoretiska beräkningar, är den termodynamiskt högsta möjliga omvandlingen. Det observerades att DME bildas genom en kombination av två metoxygrupper på katalysatorns yta, samt att bildandet av DME ökar den totala omvandlingen av CO2 till bränsle, vilken annars är begränsad till 9.5 %. Cu-Zr-SBA-15-sammansättningen användes även i läkemedelstillämpningar. De kan användas som biomaterial, e.g., fyllnadsmaterial i tandkompositer, och koppar har antibakteriella egenskaper. Dessutom kan kiseldioxid och zirkoniumdioxid vara bioaktiva vilket ses som en fördel. För denna tillämpning tillverkades Cu-Zr-SBA-15 med TEOS som kiselkälla och Inf-metoden för att växa kopparnanopartiklar. Cu-Zr-SBA-15 lämplighet som bärare av läkemedelet klorhexidindiglukonat testades in vitro. I detta fall uppvisar bäraren en laddningskapacitet [massa laddat läkemedel/(massa laddat läkemedel +massa bärare)] på 25 – 40 %. Frisättningen av läkemedel skedde i två steg. Först frisattes en stor mängd läkemedelsmolekyler. Dessa var löst placerade i håligheter i de mesoporösa stommarna. Därefter frisattes läkemedel via diffusion av molekyler som bundit till stommens yta. De två stegen representerar växelverkan mellan läkemedel – läkemedel- och läkemedel – bärare. Närvaron av zirkonium och koppar begränsar den första frisättningen och förlänger den aktiva tiden, vilket är fördelaktigt ur tillämpningsperspektiv. Effekten av porstorlek hos SBA-15 vid läkemedelsfrisättning undersöktes också i en studie där SBA-15 fylldes med doxycyklinhyklat. Laddningskapaciteten och mängden frisatt läkemedel och andelen av laddat läkemedel som frisätts var båda direkt proportionella mot porstorleken där frisättningen av doxycyklinhyklat dominerades av läkemedel – läkemedelsväxelverkan. Doxycyklinhyklat är en mindre molekyl jämfört med klorhexidindiglukonat och växelverkar svagare med SBA-15 på grund av sin mer anjoniska natur. Sammanfattningsvis visar arbetet den multifunktionella karaktären hos en skräddarsydd nanosammansättning, vilket ger värdefulla insikter i två användningsområden: katalys och läkemedelstransport Materialet testas sedan i två olika tillämpningar: katalys och läkemedelstransport.

Cancer is undoubtedly one of the main threats to global human health and as a result, despite significant advances in the field, new and improved cancer treatments are still in great need. Although chemotherapy (in combination with other therapies) is widely used to suppress the growth of tumours, many of the current anti-cancer drugs suffer from poor selectivity and consequently severe toxicity. In order to conquer these limitations, targeted drug delivery systems have been designed and studied with the primary aim of improving the accuracy of transporting anti-cancer drugs into cancer cells and tissue areas. The overall aim of the work presented in this thesis is to design new anti-cancer drug delivery systems using three different strategies. In Chapter 2, intelligent stimulus-responsive short elastin-like peptides (ELPs) and elastin-based side chain polymers (ESPs) were synthesised. The conformation and aggregation properties of these ELPs and ESPs were studied in different aqueous buffers (varying pH also) using ultraviolet-visible (UV-Vis) spectroscopy and circular dichroism (CD). Of the ELPs investigated, peptide 10 (N-acetylated VPGVG) was found to have the lowest transition temperature at pH 7 (i.e. 45oC). Amongst all the ESPs, PF100-GABA(VPGVG) (29) was proven to have the lowest transition temperature (47oC) which was most likely due to the fact that it had the highest molecular weight. In Chapter 3, gold nanoparticles (GNPs) were synthesised and functionalised with biomolecules including elastin-like peptides (ELPs), elastin-based side chain polymers (ESPs) and the pro-apoptotic peptide D-(KLAKLAK)2 (KLA). The hybrids materials, ELP-GNPs and ESP-GNPs were characterized by UV-Vis, CD and transmission electron microscopy (TEM). The hybrids showed the same temperature sensitive properties as the free ELPs and ESPs previously studied, confirming the successful functionalization of GNPs. The KLA-GNPs were found to have increased anti-cancer activity against HeLa cells compared to the free KLA. In Chapter 4, the pro-apoptotic KLA peptide was conjugated to a series of cell penetrating peptoids (CPPos) to prepare peptoid-peptide hybrids (CPPos-KLA). The anti-cancer, antimicrobial and cell penetrating properties of these peptoid-peptide hybrids were investigated. The results demonstrated an increasing trend in anti-cancer ability of CPPos-KLA hybrids (compared to free KLA) and KLA-CPPo6 (57) gave the lowest IC50 value (ca.8 μM) against HeLa cells.