Thèses sur le sujet « Delayed releases »
Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres
Consultez les 29 meilleures thèses pour votre recherche sur le sujet « Delayed releases ».
À côté de chaque source dans la liste de références il y a un bouton « Ajouter à la bibliographie ». Cliquez sur ce bouton, et nous générerons automatiquement la référence bibliographique pour la source choisie selon votre style de citation préféré : APA, MLA, Harvard, Vancouver, Chicago, etc.
Vous pouvez aussi télécharger le texte intégral de la publication scolaire au format pdf et consulter son résumé en ligne lorsque ces informations sont inclues dans les métadonnées.
Parcourez les thèses sur diverses disciplines et organisez correctement votre bibliographie.
Le, Fessant Elouan. « Etude expérimentale de la revaporisation de dépôt de produits de fission en cas d'accident grave ». Electronic Thesis or Diss., Université de Lille (2022-....), 2023. https://pepite-depot.univ-lille.fr/ToutIDP/EDSMRE/2023/2023ULILR011.pdf.
In order to improve the prediction of possible delayed radioactive releases during a SA of a PWR, remobilization phenomena of Fission Product (FP) deposited in the Reactor Cooling System (RCS) have been investigated. These phenomena induce a modification of the FP state to gaseous species or aerosols suspended in the gas flow contributing to these delayed releases. This work, within the OECD ESTER project, is focusing on the revaporization of Cs and I as main contributors to radiological consequences. In addition, tellurium (Te) which may be a source of I by radioactive decay is also studied. To do so, two complementary methodologies are used:- Revaporization experiments aim at assessing the revaporization rate of each studied element, at identifying the revaporized species, and finally at characterizing the remaining solid species.- Thermodynamic simulations aim at defining the main revaporization reactions and the airborne species.Different simulants for FP deposits in the RCS were considered: CsI, CsOH, CdI2, H2TeO4 TeO2. Thanks to the ATMIRE experimental setup covering a large range of temperatures (from 200 to 600 °C), a large range of air partial pressures (from 4.5.10-4 to 0.5 atm) complemented by steam boron vapors in the carrier gas, revaporization behaviors of Cs, I, Cd and Te were characterized. The samples were characterized thanks to combined chemical and surface analyses such as ICP-MS, XPS, and ToF-SIMS. Thanks to these techniques, identification and quantification of both gaseous and solid species formed throughout the tests were possible. Then experimental results were compared to thermodynamic calculations to confirm the main revaporization paths of each FP simulant.Above 400 °C, the CsI revaporization result in both CsI vaporization and decomposition under an air/steam atmosphere. CsI decomposition leads to the formation of gaseous iodine (HOI, I, or I2) and Cs species such as CsOH and CsNO3 as well as Cs2CrO4 (due to Cs interaction with oxidized SS) or CsBO2 (by interaction with boron in the revaporization atmosphere).Under steam/air atmosphere, CdI2 is totally decomposed above 200 °C leading to the formation of gaseous I (mainly I2) and Cd (such as CdO or Cd(OH)2).Finally, at high temperatures (above 400 °C), H2TeO4 is reduced and dehydrated to form TeO2 whatever the proportion of air (from 4.5.10-4 atm to 1 atm). For TeO2, revaporization is not influenced by Pair but is strongly increased in presence of CsOH with the formation of Cs-Te-O species (such as Cs2TeO3 or Cs2TeO4)
Lee, Wang Wang. « Factors affecting drug release and absorption from a novel oral delayed release drug delivery system ». Thesis, Durham University, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269886.
Wiedmann, Markus. « Vergleichende Untersuchungen von Delayed Release-Systemen in Abhängigkeit von Wirkstoffeigenschaften ». Diss., lmu, 2001. http://nbn-resolving.de/urn:nbn:de:bvb:19-3822.
Soutar, Sonia Anne. « Novel approaches to both delay and enhance the onset of paracetamol induced analgesia ». Thesis, University of Strathclyde, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366788.
Riley, Stuart Anthony. « Studies of delayed-release mesalazine in the treatment of ulcerative colitis ». Thesis, University of Leeds, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.413189.
McConville, Jason Thomas. « Pulse-release drug delivery and development of the time-delayed capsule ». Thesis, University of Strathclyde, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248923.
Hodges, Lee Ann. « Formulation strategies in developing an oil-filled capsule for time-delayed release ». Thesis, University of Strathclyde, 2005. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=21564.
Wu, Xue Shen. « Synthesis of hydrogel-liposome composites and their application to controlled release of active agents / ». Thesis, Connect to this title online ; UW restricted, 1992. http://hdl.handle.net/1773/8081.
Carlson, Paul Albin. « Lipid high-axial-ratio microstructures as pharmaceutical delivery systems : a physical characterization of the mechanisms behind drug release / ». Thesis, Connect to this title online ; UW restricted, 1999. http://hdl.handle.net/1773/8111.
Plummer, Bradley N. « Spontaneous Calcium Oscillations During Diastole in the Whole Heart : The Influence of Ryanodine Reception Function and Gap Junction Coupling ». Case Western Reserve University School of Graduate Studies / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=case1291050320.
Littlefield, Dennis Howard, et Eric Harley Summers. « Indicators of delay between recommendation for community outpatient treatment and release into a conditional release program ». CSUSB ScholarWorks, 1996. https://scholarworks.lib.csusb.edu/etd-project/1184.
Ronchi, Federica. « DEVELOPMENT OF INNOVATIVE MODIFIED-RELEASE LIQUID ORAL DOSAGE FORMS ». Doctoral thesis, Universite Libre de Bruxelles, 2020. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/312267.
Doctorat en Sciences biomédicales et pharmaceutiques (Pharmacie)
info:eu-repo/semantics/nonPublished
Dry, Carolyn. « Design of systems for time delayed activated internal release of chemicals in concrete from porous fibers, aggregates of prills, to improve durability / ». This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-05222007-091330/.
Fannin, Christopher A. « Linear Modeling and Analysis of Thermoacoustic Instabilities in a Gas Turbine Combustor ». Diss., Virginia Tech, 2000. http://hdl.handle.net/10919/28400.
Ph. D.
Dry, Carolyn Minnetta. « Design of systems for time delayed activated internal release of chemicals in concrete from porous fibers, aggregates of prills, to improve durability ». Diss., Virginia Tech, 1991. http://hdl.handle.net/10919/37870.
Ph. D.
Lee, Kyujin C. « Self-assembled lipopeptide prodrug depot for sustaned [sic] release : design and synthesis of peptide glutamic acid dialkylamides, their self-assembly into tubules, and their stability to proteolytic degradation / ». Thesis, Connect to this title online ; UW restricted, 1999. http://hdl.handle.net/1773/9276.
Anaya, Castro Maria Antonieta. « Optimisation de la pH-sensibilité de protéines végétales en vue d'améliorer leurs capacités d'encapsulation de principes actifs destinés à la voie orale ». Thesis, Toulouse, INPT, 2018. http://www.theses.fr/2018INPT0017/document.
In the pharmaceutical field, the oral route remains the preferred route of administration because it is simpler and better accepted by patients. However, this mode of administration is problematic for many active pharmaceutical ingredients (API) with low solubility, low permeability and/or instability in the gastrointestinal environment. Their microencapsulation in polymeric matrices can make them able to respond to these factors, especially if the microparticles generated resist the environments encountered during the gastrointestinal tract and then play a protective role, both for the API and for the mucous membranes encountered. The search for new excipients, from agroresources such as natural polymers, is booming. Vegetable proteins, thanks to their functional properties such as good solubility, relatively low viscosity, and emulsifying and film-forming properties, are preferred candidates. In addition, the great diversity of their functional groups makes it possible to envisage various chemical or enzymatic modifications. The aim of this work was to study the interest of soy protein as a coating material for API intended for the oral route, and more particularly as a candidate for the development of gastro-resistant forms. A soy protein isolate (SPI) was used as a coating material and the atomization as a process. Ibuprofen, a nonsteroidal anti-inflammatory drug, was chosen as a model molecule because of its low solubility requiring an improvement in its bioavailability, and its gastric side effects requiring an enteric shaping. Two chemical modifications of proteins (acylation and succinylation) have been studied in order to modify the solubility of the soy protein. These modifications were carried out in accordance with the principles of Green Chemistry, especially in the absence of organic solvent. The microcapsules obtained by spray-drying were characterized in terms of rate and encapsulation efficiency, morphology and size distribution of the particles, physical state of the encapsulated API and capacity of release in simulated gastric and intestinal medium. The results obtained validated the interest of the chemical modifications of the soy protein to modulate the release kinetics of API. The chemical modifications appeared particularly suitable for the encapsulation of hydrophobic active ingredients, and allowed to obtain ibuprofen release kinetics decreased to acidic pH (gastric). The last part of this work allowed to validate this last hypothesis by the realization of gastro-resistant forms on the model of MUPS tablets (multiple unit pellet system). The results of this exploratory work demonstrate that soy protein, combined with a multiparticle shaping process coupled with direct compression, can be a biosourced, environmentally friendly alternative (aqueous solvent handling, drying and compression steps reduced) and confident to the coating used in traditional gastroresistant forms
Sun, Yu. « Risk-based framework for freight movement analysis ». Thesis, Queensland University of Technology, 2002.
Grasreiner, Sebastian. « Combustion modeling for virtual SI engine calibration with the help of 0D/3D methods ». Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2012. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-90518.
Moderne Ottomotoren spielen heute sowohl in konventionellen als auch hybriden Fahrzeugantrieben eine große Rolle. Aktuelle Konzepte sind hochvariabel bezüglich Ventilsteuerung, Kraftstoffeinspritzung und Laststeuerung und ihre Optimierungspotentiale erwachsen zumeist aus neuen Softwarefunktionen. Deren Applikation ist zeit- und kostenintensiv und soll durch virtuelle Methoden unterstützt werden. In der vorliegenden Arbeit wird ein physikalisches 0D Verbrennungsmodell für Ottomotoren aufgebaut und bis zur praktischen Anwendung geführt. Dafür wurde zuerst die Thermodynamik echtzeitfähig modelliert und im gesamten Motorenkennfeld abgeglichen. Der Aufbau eines neuen Turbulenzmodells auf Basis der quasidimensionalen k-epsilon-Gleichung ermöglicht anschließend, die veränderlichen Einflüsse globaler Ladungsbewegung auf die Turbulenz abzubilden. Für den Brennverzug wurde ein vereinfachtes Modell abgeleitet, welches den Übergang von laminarer zu turbulenter Flammenausbreitung nach der Zündung in den Vordergrund stellt. Der restliche Brennverlauf wird durch die physikalische Ermittlung der turbulenten Brenngeschwindigkeit in einem 0D Entrainment-Ansatz dargestellt. Nach Validierung aller Teilmodelle erfolgt die virtuelle Bedatung der Momentenstruktur und der Abgastemperaturfunktion für das Motorsteuergerät
Tsai, Ying-Chih, et 蔡穎芝. « Release and stability studies of mesalamine delayed-release formulations ». Thesis, 2014. http://ndltd.ncl.edu.tw/handle/fnee8w.
嘉南藥理大學
藥學系
102
Controlled release system has a number of advantages, however various excipients and storage conditions might affect release characteristics as well as chemical structure integrity, and thus many affect system quality. The purpose of this study is to investigates stability of mesalamine by using forced-degradation, and then to study effects of core and coating excipients on drug release. Different percentages of povidone K30 and sodium starch glycolate were used in the core tablet. Various percentages of Eudragit S100 and Povidone K30 were coated on the core tablet to produce delayed-release formulations. The chemical stability of the coated tablet under accelerated stability condition was also evaluated. In summary, the forced degradation tests demonstrate that mesalamine is very stable in acid, UV and heat, but not stable in the base and H2O2. The dissolution results show that mesalamine release rates from core tablet can be controlled by binder and disintegrant. Different percentages and thickness of Eudragit S100 and Povidone K30 coating may control the release profile of the delayed-release formulations. By using accelerated stability condition, we can observe limited of mesalamine degradation and is acceptable according to ICH Q3B.
Chen, Shuen-Jiu, et 陳順居. « Study of Coating Materials on Oral Enteric Drugs for Delayed Release ». Thesis, 2013. http://ndltd.ncl.edu.tw/handle/61516294863211778861.
國立臺北科技大學
化學工程研究所
101
The enteric coating material coated drug controlled release technology is widely used in solid pharmaceutical, and to delay the release of drugs in the stomach so that it is released in the small intestine. Drugs coated with an enteric coating, there are three main factors: (1) Prevent the active substance in the acidic environment of the stomach degradation (2) To avoid contact with drugs and stomach, causing stomach bleeding and ulcers and other phenomena, prevent stomach digestive function (3) Controlling drug release in the intestine, to achieve effective absorption This experiment is to use the Coating pan coated on prescription drugs as the machines that will pre-coated with an enteric coating materials and medicines, first mixed into a coating solution is sprayed on the sugar pills use spray gun surface coated finish is followed by drying with hot air, it will form a film coating of pharmaceutical, during sieving to obtain adequate particle size, surface area. Received in the 8th and the 10th standard sieve material between the controlled release dosage form enteric coating multiple layers drugs, respectively, weighed appropriate quality control different pH values (artificial gastric juice: pH = 1.2, simulated intestinal fluid: pH = 6.8 , distilled water) buffer, for three groups delayed release in vitro dissolution test, and finally the use of UV measurements controlled release dosage form of this drug release pellets situation. The experimental results show that: I. particles coated controlled release formulations (pellets) and Hydroxypropyl cellulose (Hydroxypropyl cellulose; HPC) and ethyl cellulose (Ethyl cellulose; EC) such as film-coated release after coating for pharmaceuticals effects. II. Film-coated coated factors: (1) The composition of the solution film coated (2) coated with a bowl speed, the amount of coating liquid spray (3) coating process III. In the present study found that, for different controlled release dosage form, or mechanism, and there are differences between the principle, but in the end be able to achieve through the deployment of controlled prescription drugs stable release, and to achieve long-term release of drugs effects.
Govender, Mershen. « Sequential delivery of antibiotics and probiotics employing a dual release mechanism ». Thesis, 2015. http://hdl.handle.net/10539/17357.
Wiedmann, Markus [Verfasser]. « Vergleichende Untersuchungen von Delayed Release-Systemen in Abhängigkeit von Wirkstoffeigenschaften / vorgelegt von Markus Wiedmann ». 2001. http://d-nb.info/962866784/34.
Chan, Ya-wen, et 詹雅雯. « Formulation Studies of Delayed Release Pellets Using Extrusion╱Spheronization on Didanosine and Doxycycline Hyclate ». Thesis, 2007. http://ndltd.ncl.edu.tw/handle/56495852064346698187.
嘉南藥理科技大學
生物科技研究所
95
The purpose of this study is to prepare and evaluate enteric coated pellets after extrusion/spheronization. The various formulation variables studied, including pellet size, amount of enteric polymer (coating thickness) and soluble polymer/enteric polymer ratio were found to affect drug release kinetics in various dissolution media. Both Didanosine and Doxycycline Hyclate were used as model drugs. Didanosine (DDI) is known to be effective in the treatment of patients with HIV virus by inhibiting HIV replication. DDI is an acid labile drug, therefore it has to be coated with enteric polymer in order to protect the drug in the stomach and to be released in intestine. Doxycycline Hyclate belongs to Tetracyclines antibiotics. DXH is irritant to stomach, thus to release the drug in intestine via enteric coating is necessary to reduce adverse effects. In the process of preparing drug containing pellets, the uncoated pellets are formed using extrusion/spheronization methodology. The granulation solvent mixed with the model drug and water soluble materals, a binder, and a disintegrant, to form a wet mass. The wet mass was extruded/spheronized and then dried to form uncoated pellets. Enteric coating of model drug are available after polymer coating process. Various formulation variables, including pellet size, amount of enteric polymer (coating thickness) and soluble polymer/enteric polymer ratio were found to affect drug release kinetics. On the pellet size, formulations with larger size have slower release rate. Uncoated pellets have faster drug release, where as pellets with thicker polymer coating results in slower drug release. Finally, pellets with higher HPMCP/HPMC ratio of polymer coating results in slower drug release. According to the results, via adjusting appropriate formulation variables, delayed release of model drugs is achievable in order to avoid drug degradation and drug irritation in stomach.
Schilling, Sandra Ursula. « Implications of plasticization on the properties of hot-melt extruded oral dosage forms ». 2009. http://hdl.handle.net/2152/7527.
text
Chan, Judy. « Characterisation of delayed release granules for diphacinone : formulation for the control of brushtail possum in New Zealand ». 2009. http://hdl.handle.net/2292/5483.
« Development of a sustained-release microsphere formulation for delicate therapeutic proteins using a novel aqueous-aqueous emulsion technology ». 2008. http://library.cuhk.edu.hk/record=b5896772.
Thesis submitted in: December 2007.
Thesis (M.Phil.)--Chinese University of Hong Kong, 2008.
Includes bibliographical references (leaves 80-87).
Abstracts in English and Chinese.
TITLE PAGE --- p.i
ABSTRACT --- p.ii
中文摘要 --- p.v
ACKNOWLEDGEMENTS --- p.vii
TABLE OF CONTENTS --- p.viii
LIST OF FIGURES --- p.xi
LIST OF TABLES --- p.xiv
ABBREVIATIONS --- p.xv
Chapter CHAPTER 1. --- Introduction
Chapter 1.1. --- Rationale of the Study --- p.1
Chapter 1.2. --- Current technologies for formulating long-acting parenteral protein deliver system --- p.3
Chapter 1.2.1. --- Chemical Modification --- p.3
Chapter 1.2.2. --- Sustained-release formulation --- p.4
Chapter 1.2.2.1. --- Phase separation method --- p.4
Chapter 1.2.2.2. --- Solvent evaporation/extraction method --- p.5
Chapter 1.2.2.3. --- Spray drying method --- p.6
Chapter 1.2.2.4. --- Causes for protein instability --- p.6
Chapter 1.2.2.4.1. --- Water/organic solvent interface --- p.6
Chapter 1.2.2.4.2. --- Lyophilization --- p.8
Chapter 1.2.2.4.3. --- Polymer --- p.11
Chapter 1.2.2.4.4. --- Stabilizing additive --- p.13
Chapter 1.3. --- Aqueous-aqueous emulsion technology --- p.17
Chapter 1.3.1. --- Background --- p.17
Chapter 1.3.2. --- Basic Principle --- p.17
Chapter 1.3.3. --- Phase diagram --- p.18
Chapter 1.3.4. --- Formation of aqueous-aqueous emulsion --- p.19
Chapter 1.3.4.1. --- Introduction of a water-soluble charged polymer as stabilizer --- p.19
Chapter 1.3.4.2. --- Freezing-induced phase separation --- p.20
Chapter 1.3.5. --- General Protocol --- p.21
Chapter 1.3.5.1. --- Introduction of a water-soluble charged polymeric stabilizer --- p.22
Chapter 1.3.5.2. --- Freezing-induced phase separation --- p.22
Chapter 1.3.6. --- Merits and limitations of the aqueous-aqueous emulsion technology --- p.23
Chapter 1.3.7. --- Protein selection for the sustained release formulation --- p.25
Chapter 1.4. --- Aims and scope of study --- p.26
Chapter "CHAPTER 2," --- Materials and Methods
Chapter 2.1. --- Materials --- p.28
Chapter 2.1.1. --- Proteins --- p.28
Chapter 2.1.2. --- Polymers --- p.28
Chapter 2.1.3. --- Media for TF-1 Cell Culture --- p.28
Chapter 2.1.4. --- Chemicals and Solvents for Cell Proliferation Assay --- p.29
Chapter 2.1.5. --- Other Chemicals and Solvents --- p.29
Chapter 2.1.6. --- Materials for Cell Culture --- p.29
Chapter 2.1.7. --- Materials for Reagent Kits --- p.30
Chapter 2.2. --- Methods --- p.30
Chapter 2.2.1. --- Determination of the Partition Coefficients of Proteins Between PEG and Dextran --- p.30
Chapter 2.2.2. --- Preparation of Glassy Particles --- p.31
Chapter 2.2.2.1. --- Standard Stable Aqueous-aqueous Emulsion Method --- p.31
Chapter 2.2.2.2. --- Freezing-induced Phase Separation --- p.32
Chapter 2.2.3. --- Preparation of Protein-loaded and Blank Microspheres Using S-o-w Solvent Extraction Technique --- p.32
Chapter 2.2.4. --- Optical Microscopy and Scanning Electron Microscopy --- p.33
Chapter 2.2.5. --- Determination of Protein Loading --- p.34
Chapter 2.2.5.1. --- Within Dextran Particles --- p.34
Chapter 2.2.5.2. --- Within PLGA microspheres --- p.34
Chapter 2.2.6. --- Evaluation of Protein Structural Integrity and Bioactivity in Dextran Particles and PGLA Microspheres --- p.35
Chapter 2.2.7. --- In vitro Release Study --- p.36
Chapter 2.2.8. --- RhIFN Stability Determination under Simulated In Vitro Release Conditions --- p.37
Chapter 2.2.8.1. --- In the Absence of PLGA --- p.37
Chapter 2.2.8.2. --- In the Presence of PLGA --- p.37
Chapter 2.2.9. --- MicroBCÁёØ Protein Assay --- p.38
Chapter 2.2.10. --- Size Exclusion Chromatography (SEC) - High Performance Liquid Chromatography (HPLC) --- p.38
Chapter 2.2.11. --- ELISA --- p.39
Chapter 2.2.12. --- Bioactivity Assay --- p.40
Chapter 2.2.12.1. --- RhIFN --- p.40
Chapter 2.2.12.2. --- RhGM-CSF --- p.41
Chapter CHAPTER 3. --- Results and Discussions
Chapter 3.1. --- Sustained-release RhIFN Formulation --- p.45
Chapter 3.1.1. --- Partition Coefficient of RhIFN --- p.45
Chapter 3.1.2. --- Formulation Based on the Standard Aqueous-aqueous Emulsion (SA-AE) Method With Sodium Alginate as Stabilizer --- p.45
Chapter 3.1.2.1. --- Surface Morphology --- p.45
Chapter 3.1.2.2. --- Formulation Characterization --- p.46
Chapter 3.1.2.3. --- In Vitro Release of RhIFN from PLGA Microsheres --- p.54
Chapter 3.1.3. --- Formulation Based on the Freezing-induced Phase Separation (FIPS) Technique without Sodium Alginate --- p.56
Chapter 3.1.3.1. --- Formulation Characterization --- p.56
Chapter 3.1.3.2. --- In Vitro Release of RhIFN from PGLA Microsphees --- p.59
Chapter 3.2. --- RhIFN Stability Assessment under Simulated In Vitro Release Conditions --- p.63
Chapter 3.2.1. --- In the Absence of PLGA --- p.63
Chapter 3.2.2. --- In the Presence of PLGA --- p.65
Chapter 3.3. --- Sustained-release RhGM-CSF Formulation --- p.68
Chapter 3.3.1. --- Partition Coefficient Determination of RhGM-CSF Between PEG and Dextran --- p.68
Chapter 3.3.2. --- Formulation Based on Freezing-induced Phase Separation --- p.68
Chapter 3.3.2.1. --- Validation of MTT Assay Conditions --- p.69
Chapter 3.3.2.2. --- Formulation Characterization --- p.71
Chapter 3.3.2.3. --- In Vitro Release of RhGM-CSF from PLGA Microspheres --- p.75
Chapter CHAPTER 4. --- Conclusion and Future Studies
Chapter 4.1. --- Conclusion --- p.78
Chapter 4.2. --- Future Studies --- p.79
References --- p.80
Fedchyshyn, Michael John. « The Influence of Release Modality on Synaptic Transmission at a Developing Central Synapse ». Thesis, 2008. http://hdl.handle.net/1807/19487.
Umerska, A., Krzysztof J. Paluch, M. J. Santos-Martinez, C. Medina, O. I. Corrigan et L. Tajber. « Chondroitin-based nanoplexes as peptide delivery systems-Investigations into the self-assembly process, solid-state and extended release characteristics ». Thesis, 2015. http://hdl.handle.net/10454/9416.
A new type of self-assembled polyelectrolyte complex nanocarrier composed of chondroitin (CHON) and protamine (PROT) was designed and the ability of the carriers to bind salmon calcitonin (sCT) was examined. The response of sCT-loaded CHON/PROT NPs to a change in the properties of the liquid medium, e.g. its pH, composition or ionic strength was studied and in vitro peptide release was assessed. The biocompatibility of the NPs was evaluated in Caco-2 cells. CHON/PROT NPs were successfully obtained with properties that were dependent on the concentration of the polyelectrolytes and their mixing ratio. X-ray diffraction determined the amorphous nature of the negatively charged NPs, while those with the positive surface potential were semi-crystalline. sCT was efficiently associated with the nanocarriers (98-100%) and a notably high drug loading (13-38%) was achieved. The particles had negative zeta potential values and were homogenously dispersed with sizes between 60 and 250 nm. CHON/PROT NPs released less than 10% of the total loaded peptide in the first hour of the in vitro release studies. The enthalpy of the decomposition exotherm correlated with the amount of sCT remaining in NPs after the release experiments. The composition of medium and its ionic strength was found to have a considerable influence on the release of sCT from CHON/PROT NPs. Complexation to CHON markedly reduced the toxic effects exerted by PROT and the NPs were compatible and well tolerated by Caco-2 cells.