Journal articles on the topic 'Long-acting release kinetics'

Chronic hepatitis C virus (HCV) infection is a leading cause of cirrhosis worldwide and kills more Americans than 59 other infections, including HIV and tuberculosis, combined. While direct-acting antiviral (DAA) treatments are effective, limited uptake of therapy, particularly in high-risk groups, remains a substantial barrier to eliminating HCV. We developed a long-acting DAA system (LA-DAAS) capable of prolonged dosing and explored its cost-effectiveness. We designed a retrievable coil-shaped LA-DAAS compatible with nasogastric tube administration and the capacity to encapsulate and release gram levels of drugs while resident in the stomach. We formulated DAAs in drug–polymer pills and studied the release kinetics for 1 mo in vitro and in vivo in a swine model. The LA-DAAS was equipped with ethanol and temperature sensors linked via Bluetooth to a phone application to provide patient engagement. We then performed a cost-effectiveness analysis comparing LA-DAAS to DAA alone in various patient groups, including people who inject drugs. Tunable release kinetics of DAAs was enabled for 1 mo with drug–polymer pills in vitro, and the LA-DAAS safely and successfully provided at least month-long release of sofosbuvir in vivo. Temperature and alcohol sensors could interface with external sources for at least 1 mo. The LA-DAAS was cost-effective compared to DAA therapy alone in all groups considered (base case incremental cost-effectiveness ratio $39,800). We believe that the LA-DAA system can provide a cost-effective and patient-centric method for HCV treatment, including in high-risk populations who are currently undertreated.

ABSTRACTMother-to-child transmission (MTCT) of HIV-1 remains a global health problem. The World Health Organization (WHO) recommendations advise the administration of a once-daily, oral, prophylactic regimen of the nonnucleoside reverse transcriptase inhibitor nevirapine (NVP) from birth until 4 to 6 weeks of age for infants born to HIV-infected mothers in regions without access to safe and nutritionally adequate alternatives to breast milk. A critical factor driving the successful implementation of the WHO guidelines involves sustaining high adherence to the frequent dosing. With these challenges in mind, we have developed the first injectable, sustained-release NVP formulations with the goal of providing, for 6 weeks or longer, preventative plasma drug levels from a single subcutaneous administration at birth. The long-acting NVP consists of large (>50 μm), monodisperse NVP particles coated with biocompatible polymers that control the drug release kinetics. Two lead formulations exhibiting burst-free, sustained-release kinetics for up to 75 daysin vitrowere developed. Subsequentin vivostudies in rats demonstrated no toxicity related to the formulations. Rat plasma NVP concentrations were above the analytical assay's limit of quantification for up to 28 days. Pharmacokinetic analysis of the rat plasma NVP concentration-time data allowed absorption rate constants to be calculated. These data then were used to simulate infant NVP exposure from a single injected dose (<200 mg) of our long-acting formulations, demonstrating preliminary feasibility of the technology to maintain safe, preventative NVP plasma levels (0.2 to 3.0 μg ml−1) for 6 weeks or longer.

Schizophrenia, a psychiatric disorder, requires long-term treatment; however, large fluctuations in blood drug concentration increase the risk of adverse reactions. We prepared a long-term risperidone (RIS) implantation system that can stabilize RIS release and established in-vitro and in-vivo evaluation systems. Cumulative release, drug loading, and entrapment efficiency were used as evaluation indicators to evaluate the effects of different pore formers, polymer ratios, porogen concentrations, and oil–water ratios on a RIS implant (RIS-IM). We also built a mathematical model to identify the optimized formulation by stepwise regression. We also assessed the crystalline changes, residual solvents, solubility and stability after sterilization, in-vivo polymer degradation, pharmacokinetics, and tissue inflammation in the case of the optimized formulation. The surface of the optimized RIS microspheres was small and hollow with 134.4 ± 3.5 µm particle size, 1.60 SPAN, 46.7% ± 2.3% implant drug loading, and 93.4% entrapment efficiency. The in-vitro dissolution behavior of RIS-IM had zero-order kinetics and stable blood concentration; no lag time was released for over three months. Furthermore, the RIS-IM was not only non-irritating to tissues but also had good biocompatibility and product stability. Long-acting RIS-IMs with microspheres and film coatings can provide a new avenue for treating schizophrenia.

In recent pharmaceutical applications, an active pharmaceutical ingredient (API) can be mixed with a polymer material to yield a composite long-acting drug-delivery device. These devices boast higher patient compliance, localized drug delivery, and lower dosage concentrations, which can increase patient safety. As a laboratory-safe option, calcium carbonate (CaCO3) was used as a drug surrogate to mimic the release kinetics of a low-solubility API. The release of CaCO3 from a poly(ethylene vinyl acetate) (EVA) polymer matrix was studied in ultra-high-purity water. The geometry of CaCO3, along with the manufacturing technique, was manipulated to study the implications on surrogate drug release. It was found that injection molding proved to yield higher burst release, due to higher pressures achievable during manufacturing. The extrusion process can affect the surface concentration of the pharmaceutical ingredient when extruded through a water bath, resulting in a lower initial burst concentration. Regarding CaCO3 geometry, the particle size was more critical than the surface area in terms of CaCO3 release. Larger particles showed a higher release rate, though they also displayed higher variability in release. These data can be used to engineer specific release profiles when designing composite formulations and manufacturing methods for pharmaceutical-drug-delivery applications.

Implants are readily applied as a convenient method of therapy. There is great interest in the prolonged release of active substances from implants. The objective of this work was to evaluate the dissolution kinetics of steroidal anti-inflammatory preparation (SAP) released from novel implants, and to test the influence of the technology on SAP release kinetics. The proposed long-acting preparations may overcome difficulties resulting from repeated injections and often visits to ambulatory clinic, as the stabilizing function of the artificial ligament would be enriched with pharmacological activity. The potential advantages provided by the new coatings of knee implants include the continuous, sustained, and prolonged release of an active substance. The study was carried out using a modified United States Pharmacopoeia (USP) apparatus 4. The amount of SAP was measured spectroscopically. It was revealed that the transport of the drug was mainly a diffusion process. The drug release kinetics was analyzed using zero-, first-, and second-order kinetics as well as Korsmeyer-Peppas, Higuchi, and Hixon-Crowell models. The highest values of the release rate constants were k0 = (7.49 ± 0.05) × 10−5 mg × min−1, k1 = (6.93 ± 0.05) × 10−6 min−1, and k2 = (7.70 ± 0.05) × 10−7 mg−1 × min−1 as calculated according to zero-, first-, and second-order kinetics equations, respectively. The values of the rate constants obtained for the slowest process were k0 = (3.63 ± 0.06) × 10−5 mg × min−1, k1 = (2.50 ± 0.03) × 10−6 min−1, and k2 = (2.80 ± 0.03) × 10−7 mg−1 × min−1. They may suggest the possibility of sustained release of betamethasone from the system. Due to the statistical analysis, differences were observed between most of the studied implants. Incubation, temperature, time of stabilization of layers, and the method of SAP deposition on the matrix affected the drug release.

In the present work, Risperidone microparticles from poly(lactic acid)/poly(hexylene succinate) (PLA-b-PHSu) block copolymers in different ratios, 95/05, 90/10 and 80/20 w/w, were examined as long-acting injectable formulations. Nuclear magnetic resonance (NMR) was used to verify the successful synthesis of copolymers. Enzymatic hydrolysis showed an increase in weight loss as the content of PHSu increased, while the cytotoxicity studies confirmed the biocompatibility of the copolymers. The polyesters were further used to encapsulate Risperidone by spray drying. The drug-loaded microparticles were studied by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray diffraction (XRD). SEM microphotographs confirmed that spherically shaped microparticles were prepared with sizes about 5–12 μm, while XRD and differential scanning calorimetry (DSC) studies evidenced that Risperidone was encapsulated in amorphous form. The drug loading and the entrapment efficiency of Risperidone were studied as well as the in vitro release from the prepared microparticles. As the content of PHSu increased, a higher release of Risperidone was observed, with PLA-b-PHSu 80/20 w/w succeeding to release 100% of RIS within 12 days. According to theoretical modeling, the kinetics of RIS release from PLA-b-PHSu microparticles is complex, governed by both diffusion and polymer erosion.

The present study evaluates the preparation of risperidone controlled release microspheres as appropriate long-acting injectable formulations based on a series of novel biodegradable and biocompatible poly(lactic acid)–poly(propylene adipate) (PLA/PPAd) polymer blends. Initially, PPAd was synthesized using a two-stage melt polycondensation method (esterification and polycondensation) and characterized by 1H-NMR, differential scanning calorimetry (DSC), and powder X-ray diffraction (XRD) analyses. DSC and XRD results for PLA/PPAd blends (prepared by the solvent evaporation method) showed that these are immiscible, while enzymatic hydrolysis studies performed at 37 °C showed increased mass loss for PPAd compared to PLA. Risperidone-polyester microparticles prepared by the oil–water emulsification/solvent evaporation method showed smooth spherical surface with particle sizes from 1 to 15 μm. DSC, XRD, and Fourier-transformed infrared (FTIR) analyses showed that the active pharmaceutical ingredient (API) was dispersed in the amorphous phase within the polymer matrices, whereas in vitro drug release studies showed risperidone controlled release rates in all PLA/PPAd blend formulations. Finally, statistical moment analysis showed that polyester hydrolysis had a major impact on API release kinetics, while in PLA/PPAd blends with high PLA content, drug release was mainly controlled by diffusion.

The goal of this study is to develop a long-acting Lansoprazole delivery system. Lansoprazole belongs to a class of antisecretory drugs known as substituted benzimidazoles, which decrease gastric acid secretion by inhibiting the (H+,K+)-ATPase enzyme system at the secretory membrane of the stomach parietal cell. Due to its mechanism of action, despite its short half-life of 1-5 hours, it can effectively block acid secretion for 24 hours. However, as his plasma concentration falls, the effect will diminish. Lansoprazole will be given as a sustained release tablet to avoid multiple dosing or to reduce the frequency of dose. Lansoprazole was produced and analysed utilizing natural and synthetic polymers such as Xanthan gum, Gellan gum, Carbopol 940 P, and Chitosan. Based on the findings of this experiment, it was determined that formulation F7 demonstrated sustained drug release for up to 12 hours in all developed formulations. Formulation (F1, F2, F3, F4, F5, and F6) were tested in vitro for drug release. For the improved formulation F7, the formulation and release kinetics were estimated. When the regression coefficient values of were evaluated, it was found that Peppas had the highest ‘r2' value, 0.952, indicating that drug release from formulations followed Peppas release kinetics. Key words: Lansoprazole, Sustain release tablets, Synthetic and Natural Polymers, formulation, evaluation

This article describes the utilization of (methoxy)poly(ethylene glycol)-b-poly(1,3-trimethylene carbonate) ((m)PEG–PTMC) diblock and triblock copolymers for the formulation of in situ forming depot long-acting injectables by solvent exchange. The results shown in this manuscript demonstrate that it is possible to achieve long-term drug deliveries from suspension formulations prepared with these copolymers, with release durations up to several months in vitro. The utilization of copolymers with different PEG and PTMC molecular weights affords to modulate the release profile and duration. A pharmacokinetic study in rats with meloxicam confirmed the feasibility of achieving at least 28 days of sustained delivery by using this technology while showing good local tolerability in the subcutaneous environment. The characterization of the depots at the end of the in vivo study suggests that the rapid phase exchange upon administration and the surface erosion of the resulting depots are driving the delivery kinetics from suspension formulations. Due to the widely accepted utilization of meloxicam as an analgesic drug for animal care, the results shown in this article are of special interest for the development of veterinary products aiming at a very long-term sustained delivery of this therapeutic molecule.

In-situ forming implants (ISFIs) represent a simple, tunable, and biodegradable polymer-based platform for long-acting drug delivery. However, drugs with different physicochemical properties and physical states in the polymer-solvent system exhibit different drug release kinetics. Although a few limited studies have been performed attempting to elucidate these effects, a large, systematic study has not been performed until now. The purpose of this study was to characterize the in vitro drug release of 12 different small molecule drugs with differing logP and pKa values from ISFIs. Drug release was compared with polymer degradation as measured by lactic acid (LA) release and change in poly(DL-lactide-co-glycolide) (PLGA) molecular weight (MW) measured by size exclusion chromatography with multi-angle laser light scattering (SEC-MALS). Drug physical state and morphology were also measured using differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). Together, these results demonstrated that hydrophilic drugs have higher burst release at 24 h (22.8–68.4%) and complete drug release within 60 days, while hydrophobic drugs have lower burst release at 24 h (1.8–18.9%) and can sustain drug release over 60–285 days. Overall, drug logP and drug physical state in the polymer–solvent system are the most important factors when predicting the drug release rate in an ISFI for small-molecule drugs. Hydrophilic drugs exhibit high initial burst and less sustained release due to their miscibility with the aqueous phase, while hydrophobic drugs have lower initial burst and more sustained release due to their affinity for the hydrophobic PLGA. Additionally, while hydrophilic drugs seem to accelerate the degradation of PLGA, hydrophobic drugs on the other hand seem to slow down the PLGA degradation process compared with placebo ISFIs. Furthermore, drugs that were in a crystalline state within the ISFI drugs exhibited more sustained release compared with amorphous drugs.

Long-acting (LA) HIV pre-exposure prophylaxis (PrEP) can mitigate challenges of adhering to daily or on-demand regimens of antiretrovirals (ARVs). We are developing a subcutaneous implant comprising polycaprolactone (PCL) for sustained delivery of ARVs for PrEP. Here we use tenofovir alafenamide (TAF) as a model drug. Previously, we demonstrated that the release rates of drugs are controlled by the implant surface area and wall thickness, and the molecular weight (MW) of PCL. Here, we further advance the implant design and tailor the release rates of TAF and the mechanical integrity of the implant through unique polymer blend formulations. In vitro release of TAF from the implant exhibited zero-order release kinetics for ~120 days. TAF release rates were readily controlled via the MW of the polymer blend, with PCL formulations of higher MW releasing the drug faster than implants with lower MW PCL. Use of polymer MW to tune drug release rates is partly explained by PCL crystallinity, as higher PCL crystalline material is often associated with a slower release rate. Moreover, results showed the ability to tailor mechanical properties via PCL blends. Blending PCL offers an effective approach for tuning the ARV release rates, implant duration, and integrity, and ultimately the biodegradation profiles of the implant.

The aim of the study is to develop a population pharmacokinetic (PPK) model, of Octreotide long acting repeatable (LAR) formulation in healthy volunteers, which describes the highly variable, multiple peak absorption pattern of the pharmacokinetics of the drug, in individual and population levels. An empirical absorption model, coupled with a one-compartment distribution model with linear elimination was found to describe the data well. Absorption was modelled as a weighted sum of a first order and three transit compartment absorption processes, with delays and appropriately constrained model parameters. Identifiability analysis verified that all twelve parameters of the structural model are identifiable. A machine learning method, i.e., cluster analysis, was performed as pre-processing of the PK profiles, to define subpopulations, before PPK modelling. It revealed that 13% of the patients deviated considerably from the typical absorption pattern and allowed better characterization of the observed heterogeneity and variability of the study, while the approach may have wider applicability in building PPK models. The final model was evaluated by goodness of fit plots, Visual Predictive Check plots and bootstrap. The present model is the first to describe the multiple-peak absorption pattern observed after octreotide LAR administration and may be useful to provide insights and validate hypotheses regarding release from PLGA-based formulations.

e14546 Background: The efficacy and safety of recombinant human IL-2 (rhIL-2; Proleukin) to treat certain cancers is limited by a short half-life, marked toxicity and selective high affinity binding to IL2Ra over IL2Rb, resulting in preferential activation of suppressive Tregs. In contrast, MDNA11 has been engineered as a long-acting IL-2 superkine with high affinity IL2Rb receptor selectivity, resulting in preferential anti-cancer effector immune cell activation. Methods: MDNA11 was characterized in both in vitro and in vivo studies including assessment of receptor binding kinetics using BLI/Octet, receptor-mediated signaling in human PMBCs, efficacy in syngeneic mouse tumor models including memory response, as well as safety and PK/PD assessments in non-human primates (NHP). Results: Unlike rhIL-2, MDNA11 does not bind to human IL2Ra but demonstrates a 30-fold higher affinity binding to human IL2Rb. This selectivity resulted in enhanced in vitro STAT5 signaling in human NK and resting CD8 T cells with diminished signaling in Tregs; validation studies in humanized mice are ongoing. In CT26 and MC38 syngeneic tumor models, MDNA11 demonstrates potent and durable efficacy as monotherapy following a Q1W dose schedule for 2 weeks. Synergy with anti-PD1 and anti-CTLA4 immune checkpoint inhibitors (ICIs) was observed and a robust immune memory response developed in all mice with complete tumor clearance. These mice were protected against relapse and tumor re-challenges for up to 8 months without any further treatment, and showed the presence of antigen-specific CD8 T cells. In binding studies with IL-2 receptors of different species, MDNA11 showed highly similar affinity towards human and cynomolgus IL2Rb, confirming the latter as a highly relevant model for toxicology study. MDNA11 was well tolerated in cynomolgus monkeys up to 0.6 mg/kg, while inducing durable (≥10 days) proliferation and expansion of NK and CD8 T cells. Effects on Tregs were minimal and there was no eosinophilia and hypotension (associated with vascular leak syndrome). At high doses of MDNA11, the most common clinical observations were transient loss of appetite and diarrhea. There was modest increase in levels of IFNg and TNFa, but no sign of cytokine release syndrome. Dosing did not trigger development of anti-drug antibodies or histopathologic evidence of pulmonary edema (a major IL-2 induced toxicity). Conclusions: MDNA11 is a long-acting IL-2 superkine that exhibits robust efficacy in mouse tumor models as a single agent and was synergistic in combination with ICIs (anti-CTLA4 and anti-PD1). In NHP, MDNA11 demonstrates selective immune effector cell activation and a favorable safety profile. These data constitute a strong framework for the design of a pivotal GLP toxicology study to further support the planned clinical study of MDNA11 either as a single agent or in combination with ICIs.

A central question in adenohypophyseal cell physiology concerns the role of transmembrane ionic fluxes in the initiation of the hormone secretion process. In the current report, we investigated the effects of the growth hormone (GH) secretagogues ghrelin and GH-releasing peptide-6 (GHRP-6) on the regulation of the functional expression of voltage-gated Na+ channels using the tumoral somatotrope GC cell line as a model. Cells were cultured under control conditions or in presence of the GH secretagogues (GHS) for 96 h, and Na+ currents ( INa) were characterized in whole cell patch-clamp experiments. GHS treatment significantly increased INa density in a dose-dependent manner. The effects of GHRP-6 were accompanied by an augment in conductance without changes in the kinetics and the voltage dependence of the currents, suggesting an increase in the number of channels in the cell membrane. Sustained inhibition of L-type Ca2+ channel activity decreased INa density and prevented the effects of the GHS, whereas long-term exposure to an L-channel agonist increased INa density and enhanced the actions of GHRP-6, indicating that Ca2+ entry through these channels plays a role in the regulation of Na+ channel expression. Likewise, GHRP-6 failed to enhance Na+ channel expression in the presence of membrane-permeable inhibitors of protein kinases A and C, as well as the Ca2+/calmodulin-dependent kinase II. Conversely, treatment with a cAMP analog or a protein kinase C activator enhanced both basal and GHS-induced secretion of GH measured by enzyme-linked immunoassay, suggesting that GHRP-6 acting through the ghrelin receptor and different signaling pathways enhances Na+ channel membrane expression, which favors hormone release from GC somatotropes.

A long-acting and slow-release material for chlorine dioxide, based on bagasse pulp (BP) was prepared with a superabsorbent resin as the slow-release substrate and agar as the cross-linking agent. The stable ClO2 solution and the acidic activator were locked into the network structure of the superabsorbent resin, which was prepared with a carboxymethyl cellulose made from bagasse pulp. Because of the network structure of the resin, the diffusion resistance was greatly increased, and the effective release time was up to 2 months. The mechanism for the release process of the ClO2 was explored, and a kinetic model was established based on modified Fick’s diffusion law. The results showed that the release process was a diffusion-controlled process. When compared with a zero-order kinetic model and a Higuchi model, the new established model had better fitting results, and it more fully reflected the release patterns and characteristics of the ClO2.

The development and application of novel nanospheres based on cationic and anionic random amphiphilic polypeptides with prolonged stability were proposed. The random copolymers, e.g., poly(l-lysine-co-d-phenylalanine) (P(Lys-co-dPhe)) and poly(l-glutamic acid-co-d-phenylalanine) (P(Glu-co-dPhe)), with different amount of hydrophilic and hydrophobic monomers were synthesized. The polypeptides obtained were able to self-assemble into nanospheres. Such characteristics as size, PDI and ζ-potential of the nanospheres were determined, as well as their dependence on pH was also studied. Additionally, the investigation of their biodegradability and cytotoxicity was performed. The prolonged stability of nanospheres was achieved via introduction of d-amino acids into the polypeptide structure. The cytotoxicity of nanospheres obtained was tested using HEK-293 cells. It was proved that no cytotoxicity up to the concentration of 500 µg/mL was observed. C-peptide delivery systems were realized in two ways: (1) peptide immobilization on the surface of P(Glu-co-dPhe) nanospheres; and (2) peptide encapsulation into P(Lys-co-dPhe) systems. The immobilization capacity and the dependence of C-peptide encapsulation efficiency, as well as maximal loading capacity, on initial drug concentration was studied. The kinetic of drug release was studied at model physiological conditions. Novel formulations of a long-acting C-peptide exhibited their effect ex vivo by increasing activity of erythrocyte Na+/K+-adenosine triphosphatase.

Biologicals are important ocular drugs that are be delivered using monthly and bimonthly intravitreal injections to treat retinal diseases, such as age-related macular degeneration. Long acting delivery systems are needed for prolongation of their dosing interval. Intravitreal biologicals are eliminated from the eye via the aqueous humor outflow. Thus, the anterior and posterior segments are exposed to the drug. We utilized a kinetic simulation model to estimate protein drug concentrations in the vitreous and aqueous humor after bolus injection and controlled release administration to the vitreous. The simulations predicted accurately the experimental levels of 5 biologicals in the vitreous and aqueous humor. The good match between the simulations and experimental data demonstrated almost complete anterior segment bioavailability, and major dose sparing with ocular controlled release systems. Overall, the model is a useful tool in the design of intraocular delivery of biologicals.

Objective: Ramipril is a long-acting angiotensin-converting enzyme inhibitor. The study aimed to design, formulate and evaluate the oral osmotic drug delivery dosage form of an anti-hypertensive drug, ramipril.Methods: The tablet was formulated using ramipril and different polymers like PVP- K30 and Ethyl cellulose. The microcrystalline cellulose (MCC - diluent), Potassium chloride, Mannitol (osmogen) and Magnesium stearate (lubricant) were used in all the formulations. All the tablets were manufactured by wet granulation method followed by film coating. Compatibility of the drug with excipients was determined by FT-IR spectral analysis. The granules were evaluated for bulk density, Carr’s index and Hausner’s ration to determine flow properties. The prepared compressed and coated tablets were evaluated for weight variation, thickness, hardness, friability, and drug content and in vitro drug release and release kinetic studies.Results: The FT-IR study revealed that drug was compatible with excipients. The flow properties of granules of most formulation were excellent. All osmotic tablet formulations had good tablet physiochemical properties as per Pharmacopeia. The drug content of all tablet batches was satisfactory. The in vitro drug release study revealed that the formulation F7 containing 100 mg of ethyl cellulose release 100% of drug in 24 h with zero order release kinetics.Conclusions: Ramipril osmotic tablet could be used for safe management of hypertension with greater novelty.

Dibucaine (DBC) is among the more potent long-acting local anesthetics (LA), and it is also one of the most toxic. Over the last decades, solid lipid nanoparticles (SLN) have been developed as promising carriers for drug delivery. In this study, SLN formulations were prepared with the aim of prolonging DBC release and reducing its toxicity. To this end, SLN composed of two different lipid matrices and prepared by two different hot-emulsion techniques (high-pressure procedure and sonication) were compared. The colloidal stability of the SLN formulations was tracked in terms of particle size (nm), polydispersity index (PDI), and zeta potential (mV) for 240 days at 4 °C; the DBC encapsulation efficiency was determined by the ultrafiltration/centrifugation method. The formulations were characterized by differential scanning calorimetry (DSC), electron paramagnetic resonance (EPR), and release kinetic experiments. Finally, the in vitro cytotoxicity against 3T3 fibroblast and HaCaT cells was determined, and the in vivo analgesic action was assessed using the tail flick test in rats. Both of the homogenization procedures were found suitable to produce particles in the 200 nm range, with good shelf stability (240 days) and high DBC encapsulation efficiency (~72–89%). DSC results disclosed structural information on the nanoparticles, such as the lower crystallinity of the lipid core vs. the bulk lipid. EPR measurements provided evidence of DBC partitioning in both SLNs. In vitro (cytotoxicity) and in vivo (tail flick) experiments revealed that the encapsulation of DBC into nanoparticles reduces its intrinsic cytotoxicity and prolongs the anesthetic effect, respectively. These results show that the SLNs produced are safe and have great potential to extend the applications of dibucaine by enhancing its bioavailability.

Background: Allogeneic hematopoietic cell transplantation (allo-HCT) is the only curative therapy for patients with high-risk and refractory acute myeloid leukemia (AML). Unfortunately, up to 50 percent of patients relapse after allo-HCT.Recent research has shown that 30-50 percent of AML samples from patients relapsing after allo-HCT have downregulation of MHC class II (MHC-II) expression, which may promote immune effector evasion and disease relapse. These studies also report that interferon gamma (IFNγ) can restore MHC-II expression. IFNγ has never been systemically administered after allo-HCT and would likely cause significant and potentially life-threatening toxicities. Reinduction of MHC-II expression may lead to re-engagement of immune effectors, restoration of the graft-versus-malignancy effect, and disease control. We hypothesized that T cell immunotherapies targeting AML cells will lead to T cell activation, localized IFNγ release, and upregulation of MHC-II on AML cells. Methods: For in vitro experiments, THP1 cells (THP1s), which have intermediate MHC-II expression, or primary human AML samples with low MHC-II expression from a patient relapsing after allo-HCT (AML-low cells) were co-cultured with or without T-cell immunotherapy and with or without human MHC-mismatched CD3+ T cells. The following T-cell immunotherapies were tested: flotetuzumab (FLZ), an investigational CD123 x CD3 bispecific DART® molecule; a CD33 x CD3 bispecific molecule (Creative Biolabs, Shirley, NY); and CD123-directed chimeric antigen receptor (CAR) T cells. THP1 IFNγ receptor-1 (IFNγR1) knockout cell lines were generated using CRISPR-Cas9. MHC-II expression was measured by flow cytometry and IFNγ concentrations via Luminex immunoflourescence assay. In order to rescue THP1s from FLZ-induced death and allow for longitudinal evaluation, a transwell plate system was used, placing THP1s, human CD3+ T cells, and FLZ in the top well and THP1s in the bottom well. This allowed for diffusion of IFNγ but not human T cells to the bottom wells, permitting MHC-II upregulation while limiting death. The upper and lower wells were coincubated together for 24 hours prior to harvesting of the THP1s in the lower well for longitudinal studies and mixed-lymphocyte reactions. For in vivo experiments, NOD-scid IL2Rgammanull mice expressing human IL-3, GM-CSF, and SCF (NSG-S) were irradiated with 250 rads and injected with 10e6 primary AML-low cells per mouse. After 5.5 weeks, mice were divided into the following groups: 1) untreated control; 2) FLZ only (2mg/kg); 3) human mismatched T cells only (10e7 T cells per mouse); 4) FLZ and T cells. Results: In vitro co-culture of THP1 or AML-low cells with FLZ and T cells led to significantly increased MHC-II expression at 48 hours when compared with the control, FLZ only, and T cell only groups (Figure 1A-B). Co-culture of THP1s with the CD123 CAR-T cells led to similar results. Although co-incubation with a CD33 x CD3 bispecific led to a similar result, the MHC-II upregulation was not nearly as dramatic as that seen with CD123 targeting agents. Using a transwell system to rescue THP1s from FLZ-mediated toxicity, FLZ-induced MHC-II upregulation on THP1s peaked at 48-72 hours (similar kinetics to what is seen with IFNγ alone). These THP1s with upregulated MHC-II activated third-party donor mismatched human CD4+ T cells to a greater extent than untreated THP1s controls. Co-cultures of THP1s with CD4+ T cells and FLZ induced the secretion of very high concentrations of IFNγ, and blockade of IFNγ signaling through knockout of IFNγR1 led to abrogation of the effect (Figure 1C-D). Finally, in an in vivo model, NSG-S mice injected with AML-low samples and treated with FLZ and T cells showed significant upregulation of MHC-II expression on the AML cells. Single cell RNA-sequencing of AML cells purified from these mice is ongoing. Conclusions: Use of FLZ and other T-cell immunotherapies targeting AML antigens led to both direct AML killing as well as significant upregulation of MHC-II expression on AML cells both in vitro and in vivo. The effect appears to be mediated primarily by IFNγ. T-cell immunotherapies represent a promising treatment approach for AML patients relapsing after allo-HCT and may lead to enhanced immune recognition in the 30-50% of patients who relapse after allo-HCT. Based on these results, a clinical trial treating patients relapsing after allo-HCT with FLZ is planned. Disclosures Christopher: Boulder Bioscience: Patents & Royalties: IP around the use of interferon gamma to treat stem cell transplant. Kim:Tmunity: Patents & Royalties: methods for gene editing in hematopoietic stem cells to enhance the therapeutic efficacy of antigen-specific immunotherapy (Licensed by University of Pennsylvania); Neoimmune Tech: Patents & Royalties: use of long-acting IL-7 analogs to enhance CAR T cells (licensed by Washington University). Muth:MacroGenics, Inc.: Current Employment, Current equity holder in publicly-traded company. Davidson:MacroGenics: Current Employment. DiPersio:Magenta Therapeutics: Membership on an entity's Board of Directors or advisory committees.

Abstract P2 receptors are functionally diverse cell surface receptors that bind nucleotides adenine (ADP, ATP) and uridine (UDP, UTP). P2Y receptors are metabotropic G protein-coupled receptors that mediate vascular and immune responses to injury. We previously reported the differential expression cloning of the UTP-glycoconjugate receptor, P2Y14 from quiescent primary human bone marrow (BM) hematopoietic stem cells (HSCs). Using P2Y14−/− mice, we now report that the presence of P2Y14 protects HSCs from apoptosis in the face of cytotoxic chemical injury. P2Y14 null mice develop normally and showed no significant differences in peripheral blood cell counts, BM cellularity or the absolute number/proportion of lin−cKit+Sca1+ (LKS+) and CD34−/lowLKS+ (34-LKS+) cells compared to their wildtype littermates. Similarly, cell cycle status, in vitro colony-forming cell (CFC) capacity, in vivo homing and in vivo colony-forming unit-spleen (CFU-S) function were unaffected. Since the role of nucleotide receptors in injury response have been reported, we examined BM HSC content following IP injection of 200mg/kg cyclophosphamide (CTX) and found that the relative protection of LKS+ and 34-LKS+ cells from CTX-induced apoptosis was lost in P2Y14 null animals (WT LKS+: 12.7% AnnexinV+7AAD-, KO LKS+ 36.8% AnnexinV+7AAD−, n=5 each, p=0.004; WT 34-LKS+: 13.2% AnnexinV+7AAD−, KO LKS+ 38.7% AnnexinV+7AAD−, n=5 each, p=0.007). In addition, the kinetics of long-term myeloid recovery after a single injection of 5-Fluorouracil (5FU) IP 150mg/kg was significantly more accentuated in P2Y14 null animals, with significantly greater peripheral blood Gr-1+ cell count at days 21–56 post-injection (n=10 each, p=0.009). When sorted BM LKS+ cells were exposed in vitro to UDP-glucose, a putative P2Y14 ligand known to be released from cytoplasm during cellular injury, BrDU incorporation was significantly reduced (n=3 each, p&lt;0.05), suggesting that P2Y14 activation with UDP-glucose reduces HSC cell cycle entry in response to injury. While these in vivo models examine HSC response to injury to both BM microenvironment and the HSCs themselves, when uninjured HSCs were reintroduced into injured microenvironment in the setting of hematopoietic reconstitution following lethal irradiation, P2Y14 null BM HSCs performed better in serial transplantation (n=10 each, p&lt;0.01 for primary, secondary and tertiary transplantation), showing greater reconstitution and self-renewal capacity compared with WT littermates. From these findings, we propose that P2Y14 protects HSCs from chemical injury by acting as a sensor for metabolic “danger signal” in the form of released intracellular UDP-glucose during acute chemical injury in the BM and maintaining relative resistance of HSCs to toxin-induced apoptosis by restricting cell cycle entry. In the setting of injury exclusive to BM microenvironment (HSC transplantation), P2Y14 null HSCs, unable to detect UDP-glucose, respond to highly proliferative environment following lethal irradiation, resulting in greater reconstitution and self-renewal.

Introduction: Glatiramer acetate (GA) is a newly emerged therapeutic peptide to reduce the frequency of relapses in multiple sclerosis (MS). Despite its good performance in controlling MS, it is not widely used due to daily or biweekly subcutaneous injections due to rapid degradation and body clearance. Therefore, implant design with sustained release leads to prolonged biological effects by gradually increasing drug exposure and protecting GA from rapid local degradation. Methods: Different emulsion methods, PLGA type, surfactant concentration, drug/polymer ratio, drying processes, stirring method, and other variables in preliminary studies modified the final formulation. The release kinetics were studied through mechanistic kinetic models such as zero-order, Weibull, Higuchi, etc. In this study, all challenges for easy scale-up, methodological detail, and a simple, feasible setup in mass production were discussed. Results: The optimized formulation was obtained by 1:6 drug/PLGA, 0.5% w/w polyvinyl alcohol, and 0.75% w/w NaCl in the external aqueous phase, 1:10 continuous phase to dispersed phase ratio, and without any surfactant in the primary emulsion. The final freeze-dried particles presented a narrow distributed size of 1-10 µm with 7.29% ± 0.51 drug loading and zero-order release behavior with appropriate regression correlation (R2 98.7), complete release, and only 7.1% initial burst release. Conclusion: Therefore, to achieve improvement in patient compliance through better and longer efficacy, designing the parenteral sustained release microspheres (MPSs) of this immune modulator is a promising approach that should be considered.

Background/Objective: Ketamine, a psychedelic, is a noncompetitive N-methyl-D-aspartate receptor antagonist that may also bind to mu opioid receptors. Historically, it has been used as an anesthetic (KetalarÒ), although now has found uses as a novel, quick acting, antidepressant for treatment-resistant depression (SpravatorÒ) and could be used as an adjuvant to opioid analgesia providing opioid-sparing effects. One major advantage over opioids is Ketamine does not suffer from respiratory depression and maintains patent airways during anesthesia. Ketamine is only available as a short-acting injectable solution or a nasal spray. Our goal is to develop a long-acting injectable form in a biodegradable matrix poly(lactic-co-glycolic) acid (PLGA) that does not have a burst release and provides 5-7 days of steady-state plasma levels. Methods: A mechanistic approach towards development of a long-acting injectable began with a solubility screen of Ketamine. Based on these results, experiments began with an oil in water emulsification with two theoretical drug loadings (25% and 40%) and two processing conditions – (1) aqueous extraction and (2) aqueous extraction, intermediate drying, and a 25% Ethanol wash. The formulations were characterized for drug loading, drug release, and crystallinity and imaged using scanning electron microscopy (SEM). Results: Minimal differences were noted in the release profiles between formulations. Although, a significant difference was noted between the two processing conditions, where the extra intermediate drying step and 25% ethanol wash resulted in a significant slowing of the drug release rate. Conclusion and Implications: The difference in release kinetics is hypothesized to be due to densification of the PLGA matrix, based on the increase in surface roughness/wrinkling in the SEM images, crystallinity increase, and on their respective powder x-ray diffraction patterns. Our preliminary results demonstrate the feasibility of a longer acting Ketamine using PLGA. Further refinement of these formulations and rodent pharmacokinetic studies will be done in future.

Objective: The aim of the present study was to optimize long-acting injectable (LAI) microspheres of Paliperidone palmitate (PP) for treatment of schizophrenia using face-centered central composite design (FC-CCD). Methods: In this study, poly lactic-co-glycolic acid (PLGA) based LAI microspheres of paliperidone palmitate (PP) were formulated by using FC-CCD. LAI microspheres were developed by using oil in water (O/W) emulsion solvent evaporation technique. On the basis of preliminary trials, FC-CCD was employed to check effect of independent variables such as drug polymer ratio (X1), homogenization speed (X2) and rate of addition (X3). While mean particle size (Y1), drug loading (Y2), entrapment efficiency (Y3), burst release (Y4), and drug release on day 60 (Y5) were considered as dependent variables and statistically evaluation performed by using design expert 12 software. Morphology of prepared microspheres was studied by using the scanning electron microscopy (SEM) technique, while particle size was analyzed by laser diffraction technique. In vitro drug release studies were performed using a controlled temperature shaking water bath apparatus. Fourier transforms infrared spectroscopy (FTIR) and differential scanning calorimetric (DSC) study were performed to analyze any changes in crystal behavior or to detect any chemical bonding between ingredients. 13C NMR and 1H NMR techniques were used to analyze end-capping and monomer ratio in developed microspheres. Results: The factorial batches mean particle size was found to be 38 µm to 104 µm and drug loading were found between 27.2 % to 47.2%. Mathematical modelling of drug release kinetics revealed that near zero-order drug release of checkpoint formulations. Endcap analysis and molar ratio of formulated microspheres were found to be ester end cap and ~75:25, respectively. Morphologically all the prepared samples were found to be spherical in shape and smooth surface. FTIR data showed no significant interactions occurred between drug and excipients. The actual responses of checkpoint formulations were observed within 5% variation of predicted values. Conclusion: The prepared microspheres showed promising results of morphology, particle size, drug loading, entrapment efficiency, burst release and drug release on day 60. The successful predictive designs models were achieved from employed FC-CCD.

Abstract Purpose Long-acting formulations of the potent antiretroviral prodrug tenofovir alafenamide (TAF) hold potential as biomedical HIV prevention modalities. Here, we present a rigorous comparison of three animal models, C57BL/6 J mice, beagle dogs, and merino sheep for evaluating TAF implant pharmacokinetics (PKs). Methods Implants delivering TAF over a wide range of controlled release rates were tested in vitro and in mice and dogs. Our existing PK model, supported by an intravenous (IV) dosing dog study, was adapted to analyze mechanistic aspects underlying implant TAF delivery. Results TAF in vitro release in the 0.13 to 9.8 mg d−1 range with zero order kinetics were attained. Implants with equivalent fabrication parameters released TAF in mice and sheep at rates that were not statistically different, but were 3 times higher in dogs. When two implants were placed in the same subcutaneous pocket, a two-week creep to Cmax was observed in dogs for systemic drug and metabolite concentrations, but not in mice. Co-modeling IV and TAF implant PK data in dogs led to an apparent TAF bioavailability of 9.6 in the single implant groups (compared to the IV group), but only 1.5 when two implants were placed in the same subcutaneous pocket. Conclusions Based on the current results, we recommend using mice and sheep, with macaques as a complementary species, for preclinical TAF implant evaluation with the caveat that our observations may be specific to the implant technology used here. Our report provides fundamental, translatable insights into multispecies TAF delivery via long-acting implants.

PurposeDescribe the pharmacokinetics of extended-release parenteral ceftiofur (Excede®) in canine tear film and compare these concentrations to minimal inhibitory concentrations (MICs) of ceftiofur against common ocular pathogens in dogs.MethodSix dogs of various breeds were enrolled. Disruption of blood-tear barrier was achieved with histamine-induced conjunctivitis to ensure clinical relevance of the results. Each dog received a single subcutaneous injection of 5 mg/kg Excede®, followed by tear collection with Schirmer strips at times 0, 0.25, 0.5, 1, 2, 4, 8, 12, 24, 36, 48, 72, 96, 120, 144, 168, 192, 216 and 240 h. Drug quantification was performed with liquid chromatography-mass spectrometry. MICs were determined for Staphylococcus pseudintermedius, Streptococcus canis and Pseudomonas aeruginosa by assessing bacterial growth (n = 10 per bacterial species) in the presence of ceftiofur at increasing concentrations.ResultsBlood-tear barrier breakdown provided tear film concentrations of ceftiofur 3.2–28.9-fold higher than in the contralateral healthy eye (n = 1 dog, pilot experiment). In all six dogs, ceftiofur concentrations in tears varied from 2.3 to 637.5 ng/mL and were detectable up to 10 days (240 h) after subcutaneous injection. However, tear levels always remained below MICs for common ocular isolates (≥640 ng/mL).ConclusionsCeftiofur reached the tear compartment (for up to 10 days) after a single parenteral injection, however tear concentrations were extremely variable and too low to be effective against common bacterial pathogens in dogs. Further studies with different ceftiofur dosage or other long-acting injectable antibiotics are warranted.

The contemporary video game market is as recognisable for its brands as it is for the characters that populate their game worlds, from franchise-leading characters like Garrus Vakarian (Mass Effect original trilogy), Princess Zelda (The Legend of Zelda franchise) and Cortana (HALO franchise) to more recent game icons like Miles Morales (Marvel's Spiderman game franchise) and Judy Alvarez (Cyberpunk 2077). Interactions with these casts of characters enhance the richness of games and their playable worlds, giving a sense of weight and meaning to player actions, emphasising thematic interests, and in some cases acting as buffers to (or indeed hindering) different aspects of gameplay itself. As Jordan Erica Webber writes in her essay The Road to Journey, “videogames are often examined through the lens of what you do and what you feel” (14). For many games, the design of interactions between the player and other beings in the world—whether they be intrinsic to the world (non-playable characters or NPCs) or other live players—is a bridging aspect between what you do and how you feel and is thus central to the communication of more cohesive and focussed work. This essay will discuss two examples of game design techniques present in Transistor by Supergiant Games and Journey by thatgamecompany. It will consider how the design of “playful” interactions between the player and other characters in the game world (both non-player characters and other player characters) can be used as a tool to align a player’s experience of “intent” with the thematic objectives of the designer. These games have been selected as both utilise design techniques that allow for this “playful” interaction (observed in this essay as interactions that do not contribute to “progression” in the traditional sense). By looking closely at specific aspects of game design, it aims to develop an accessible examination by “focusing on the dimensions of involvement the specific game or genre of games affords” (Calleja, 222). The discussion defines “intent”, in the context of game design, through a synthesis of definitions from two works by game designers. The first being Greg Costikyan’s definition of game structure from his 2002 presentation I Have No Words and I Must Design, a paper subsequently referenced by numerous prominent game scholars including Ian Bogost and Jesper Juul. The second is Steven Swink’s definition of intent in relation to video games, from his 2009 book Game Feel: A Game Designer’s Guide to Virtual Sensation—an extensive reference text of game design concepts, with a particular focus on the concept of “game feel” (the meta-sensation of involvement with a game). This exploratory essay suggests that examining these small but impactful design techniques, through the lens of their contribution to overall intent, is a useful tool for undertaking more holistic studies of how games are affective. I align with the argument that understanding “playfulness” in game design is useful in understanding user engagement with other digital communication platforms. In particular, platforms where the presentation of user identity is relational or performative to others—a case explored in Playful Identities: The Ludification of Digital Media Cultures (Frissen et al.). Intent in Game Design Intent, in game design, is generated by a complex, interacting economy, ecosystem, or “game structure” (Costikyan 21) of thematic ideas and gameplay functions that do not dictate outcomes, but rather guide behaviour and progression forward through the need to achieve a goal (Costikyan 21). Intent brings player goals in line with the intrinsic goals of the player character, and the thematic or experiential goals the game designer wants to convey through the act of play. Intent makes it easier to invest in the game’s narrative and spatial context—its role is to “motivate action in game worlds” (Swink 67). Steven Swink writes that it is the role of game design to create compelling intent from “a seemingly arbitrary collection of abstracted variables” (Swink 67). He continues that whether it is good or bad is a broader question, but that “most games do have in-born intentionality, and it is the game designer who creates it” (67). This echoes Costikyan’s point: game designers “must consciously set out to decide what kind of experiences [they] want to impart to players and create systems that enable those experiences” (20). Swink uses Mario 64 as one simple example of intent creation through design—if collecting 100 coins did not restore Mario’s health, players would simply not collect them. Not having health restricts the ability for players to fulfil the overarching intent of progression by defeating the game’s main villain (what he calls the “explicit” intent), and collecting coins also provides a degree of interactivity that makes the exploration itself feel more fulfilling (the “implicit” intent). This motivation for action may be functional, or it may be more experiential—how a designer shapes variables into particular forms to encourage the particular kinds of experience that they want a player to have during the act of play (such as in Journey, explored in the latter part of this essay). This essay is interested in the design of this compelling thematic intent—and the role “playful” interactions have as a variable that contributes to aligning player behaviours and experience to the thematic or experiential goals of game design. “Playful” Communication and Storytelling in Transistor Transistor is the second release from independent studio Supergiant Games and has received over 100 industry accolades (Kasavin) since its publication in 2014. Transistor incorporates the suspense of turn-based gameplay into an action role-playing game—neatly mirroring a style of gameplay to the suspense of its cyber noir narrative. The game is also distinctly “artful”. The city of Cloudbank, where the game takes place, is a cyberpunk landscape richly inspired by art nouveau and art deco style. There is some indication that Cloudbank may not be a real city at all—but rather a virtual city, with an abundance of computer-related motifs and player combat abilities named as if they were programming functions. At release, Transistor was broadly recognised in the industry press for its strength in “combining its visuals and music to powerfully convey narrative information and tone” (Petit). If intent in games in part stems from a unification of goals between the player and design, the interactivity between player input and the actions of the player character furthers this sense of “togetherness”. This articulation and unity of hand movement and visual response in games are what Kirkpatrick identified in his 2011 work Aesthetic Theory and the Video Game as the point in which videogames “broke from the visual entertainment culture of the last two centuries” (Kirkpatrick 88). The player character mediates access to the space by which all other game information is given context and allows the player a degree of self-expression that is unique to games. Swink describes it as an amplified impression of virtual proprioception, that is “an impression of space created by illusory means but is experienced as real by the senses … the effects of motion, sound, visuals, and responsive effects combine” (Swink 28). If we extend Swink’s point about creating an “impression of space” to also include an “impression of purpose”, we can utilise this observation to further understand how the design of the playful interactions in Transistor work to develop and align the player’s experience of intent with the overarching narrative goal (or, “explicit” intent) of the game—to tell a compelling “science-fiction love story in a cyberpunk setting, without the gritty backdrop” (Wallace) through the medium of gameplay. At the centre of any “love story” is the dynamic of a relationship, and in Transistor playful interaction is a means for conveying the significance and complexity of those dynamics in relation to the central characters. Transistor’s exposition asks players to figure out what happened to Red and her partner, The Boxer (a name he is identified by in the game files), while progressing through various battles with an entity called The Process to uncover more information. Transistor commences with player-character, Red, standing next to the body of The Boxer, whose consciousness and voice have been uploaded into the same device that impaled him: the story’s eponymous Transistor. The event that resulted in this strange circumstance has also caused Red to lose her ability to speak, though she is still able to hum. The first action that the player must complete to progress the game is to pull the Transistor from The Boxer’s body. From this point The Boxer, speaking through the Transistor, becomes the sole narrator of the game. The Boxer’s first lines of dialogue are responsive to player action, and position Red’s character in the world: ‘Together again. Heh, sort of …’ [Upon walking towards an exit a unit of The Process will appear] ‘Yikes … found us already. They want you back I bet. Well so do I.’ [Upon defeating The Process] ‘Unmarked alley, east of the bay. I think I know where we are.’ (Supergiant Games) This brief exchange and feedback to player movement, in medias res, limits the player’s possible points of attention and establishes The Boxer’s voice and “character” as the reference point for interacting with the game world. Actions, the surrounding world, and gameplay objectives are given meaning and context by being part of a system of intent derived from the significance of his character to the player character (Red) as both a companion and information-giver. The player may not necessarily feel what an individual in Red’s position would feel, but their expository position is aligned with Red’s narrative, and their scope of interaction with the world is intrinsically tied to the “explicit” intent of finding out what happened to The Boxer. Transistor continues to establish a loop between Red’s exploration of the world and the dialogue and narration of The Boxer. In the context of gameplay, player movement functions as the other half of a conversation and brings the player’s control of Red closer to how Red herself (who cannot communicate vocally) might converse with The Boxer gesturally. The Boxer’s conversational narration is scripted to occur as Red moves through specific parts of the world and achieves certain objectives. Significantly, The Boxer will also speak to Red in response to specific behaviours that only occur should the player choose to do them and that don’t necessarily contribute to “progressing” the game in the mechanical sense. There are multiple points where this is possible, but I will draw on two examples to demonstrate. Firstly, The Boxer will have specific reactions to a player who stands idle for too long, or who performs a repetitive action. Jumping repeatedly from platform to platform will trigger several variations of playful and exasperated dialogue from The Boxer (who has, at this point, no choice but to be carried around by Red): [Upon repeatedly jumping between the same platform] ‘Round and round.’ ‘Okay that’s enough.’ ‘I hate you.’ (Supergiant Games) The second is when Red “hums” (an activity initiated by the player by holding down R1 on a PlayStation console). At certain points of play, when making Red hum, The Boxer will chime in and sing the lyrics to the song she is humming. This musical harmonisation helps to articulate a particular kind of intimacy and flow between Red and The Boxer —accentuated by Red’s animation when humming: she is bathed in golden light and holds the Transistor close, swaying side to side, as if embracing or dancing with a lover. This is a playful, exploratory interaction. It technically doesn’t serve any “purpose” in terms of finishing the game—but is an action a player might perform while exploring controls and possibilities of interactivity, in turn exploring what it is to “be” Red in relation to the game world, the story being conveyed, and The Boxer. It delivers a more emotional and affective thematic idea about a relationship that nonetheless relies just as much on mechanical input and output as engaging in movement, exploration, and combat in the game world. It’s a mechanic that provides texture to the experience of inhabiting Red’s identity during play, showcasing a more individual complexity to her story, driven by interactivity. In techniques like this, Transistor directly unifies its method for information-giving, interactivity, progression, and theme into a single design language. To once again nod to Swink and Costikyan, it is a complex, interacting economy or ecosystem of thematic ideas and gameplay structures that guide behaviour and progression forward through the need to achieve a single goal (Costikyan 21), guiding the player towards the game’s “explicit” intent of investment in its “science fiction love story”. Companionship and Collaboration in Journey Journey is regularly praised in many circles of game review and discussion for its powerful, pared-back story conveyed through its exceptional game design. It has won a wide array of awards, including multiple British Academy Games Awards and Game Developer’s Choice Awards, and has been featured in highly regarded international galleries such as the Victoria and Albert Museum in London. Its director, Jenova Chen, articulated that the goal of the game (and thus, in the context of this essay, the intent) was “to create a game where people who interact with each other in an online community can connect at an emotional level, regardless of their gender, age, ethnicity, and social status” (Webber 14). In Journey, the player controls a small robed figure moving through a vast desert—the only choices for movement are to slide gracefully through the sand or to jump into the air by pressing the X button (on a PlayStation console), and gracefully float down to the ground. You cannot attack anything or defend yourself from the elements or hostile beings. Each player will “periodically find another individual in the landscape” (Isbister 121) of similar design to the player and can only communicate with them by experimenting with simple movements, and via short chirping noises. As the landscape itself is vast and unknown, it is what one player referred to as a sense of “reliance on one another” that makes the game so captivating (Isbister 12). Much like The Boxer in Transistor, the other figure in Journey stands out as a reference point and imbues a sense of collaboration and connection that makes the goal to reach the pinprick of light in the distance more meaningful. It is only after the player has finished the game that the screen reveals the other individual is a real person, another player, by displaying their gamer tag. One player, playing the game in 2017 (several years after its original release in 2012), wrote: I went through most of the game by myself, and when I first met my companion, it was right as I walked into the gate transitioning to the snow area. And I was SO happy that there was someone else in this desolate place. I felt like it added so much warmth to the game, so much added value. The companion and I stuck together 100% of the way. When one of us would fall the slightest bit behind, the other would wait for them. I remember saying out loud how I thought that my companion was the best programmed AI that I had ever seen. In the way that he waited for me to catch up, it almost seemed like he thanked me for waiting for him … We were always side-by-side which I was doing to the "AI" for "cinematic-effect". From when I first met him up to the very very end, we were side-by-side. (Peace_maybenot) Other players indicate a similar bond even when their companion is perhaps less competent: I thought my traveller was a crap AI. He kept getting launched by the flying things and was crap at staying behind cover … But I stuck with him because I was like, this is my buddy in the game. Same thing, we were communicating the whole time and I stuck with him. I finish and I see a gamer tag and my mind was blown. That was awesome. (kerode4791) Although there is a definite object of difference in that Transistor is narrated and single-player while Journey is not, there are some defined correlations between the way Supergiant Games and thatgamecompany encourage players to feel a sense of investment and intent aligned with another individual within the game to further thematic intent. Interactive mechanics are designed to allow players a means of playful and gestural communication as an extension of their kinetic interaction with the game; travellers in Journey can chirp and call out to other players—not always for an intrinsic goal but often to express joy, or just to experience and sense of connectivity or emotional warmth. In Transistor, the ability to hum and hear The Boxer’s harmony, and the animation of Red holding the Transistor close as she does so, implying a sense of protectiveness and affection, says more in the context of “play” than a literal declaration of love between the two characters. Graeme Kirkpatrick uses dance as a suitable metaphor for this kind of experience in games, in that both are characterised by a certainty that communication has occurred despite the “eschewal of overt linguistic elements and discursive meanings” (120). There is also a sense of finite temporality in these moments. Unlike scripted actions, or words on a page, they occur within a moment of being that largely belongs to the player and their actions alone. Kirkpatrick describes it as “an inherent ephemerality about this vanishing and that this very transience is somehow essential” (120). This imbuing of a sense of time is important because it implies that even if one were to play the game again, repeating the interaction is impossible. The communication of narrative within these games is not a static form, but an experience that hangs unique at that moment and space of play. Thatgamecompany discussed in their 2017 interviews with Webber, published as part of her essay for the Victoria & Albert’s Video Games: Design/Play/Disrupt exhibition, how by creating and restricting the kind of playful interaction available to players within the world, they could encourage the kind of emotional, collaborative, and thoughtful intent they desired to portray (Webber 14). They articulate how in the development process they prioritised giving the player a variety of responses for even the smallest of actions and how that positive feedback, in turn, encourages play and prevented players from being “bored” (Webber 22). Meanwhile, the team reduced responsiveness for interactions they didn’t want to encourage. Chen describes the approach as “maximising feedback for things you want and minimising it for things you don’t want” (Webber 27). In her essay, Webber writes that Chen describes “a person who enters a virtual world, leaving behind the value system they’ve learned from real life, as like a baby banging their spoon to get attention” (27): initially players could push each other, and when one baby [player] pushed the other baby [player] off the cliff that person died. So, when we tested the gameplay, even our own developers preferred killing each other because of the amount of feedback they would get, whether it’s visual feedback, audio feedback, or social feedback from the players in the room. For quite a while I was disappointed at our own developers’ ethics, but I was able to talk to a child psychologist and she was able to clarify why these people are doing what they are doing. She said, ‘If you want to train a baby not to knock the spoon, you should minimise the feedback. Either just leave them alone, and after a while they’re bored and stop knocking, or give them a spoon that does not make a sound. (27) The developers then made it impossible for players to kill, steal resources from, or even speak to each other. Players were encouraged to stay close to each other using high-feedback action and responsiveness for doing so (Webber 27). By using feedback design techniques to encourage players to behave a certain way to other beings in the world—both by providing and restricting playful interactivity—thatgamecompany encourage a resonance between players and the overarching design intent of the project. Chen’s observations about the behaviour of his team while playing different iterations of the game also support the argument (acknowledged in different perspectives by various scholarship, including Costikyan and Bogost) that in the act of gameplay, real-life personal ethics are to a degree re-prioritised by the interactivity and context of that interactivity in the game world. Intent and the “Actualities of (Game) Existence” Continuing and evolving explorations of “intent” (and other parallel terms) in games through interaction design is of interest for scholars of game studies; it also is an important endeavour when considering influential relationships between games and other digital mediums where user identity is performative or relational to others. This influence was examined from several perspectives in the aforementioned collection Playful Identities: The Ludification of Digital Media Cultures, which also examined “the process of ludification that seems to penetrate every cultural domain” of modern life, including leisure time, work, education, politics, and even warfare (Frissen et al. 9). Such studies affirm the “complex relationship between play, media, and identity in contemporary culture” and are motivated “not only by the dominant role that digital media plays in our present culture but also by the intuition that ‘“play is central … to media experience” (Frissen et al. 10). Undertaking close examinations of specific “playful” design techniques in video games, and how they may factor into the development of intent, can help to develop nuanced lines of questioning about how we engage with “playfulness” in other digital communication platforms in an accessible, comparative way. We continue to exist in a world where “ludification is penetrating the cultural domain”. In the first few months of the global COVID-19 pandemic, Nintendo released Animal Crossing: New Horizons. With an almost global population in lockdown, Animal Crossing became host to professional meetings (Espiritu), weddings (Garst), and significantly, a media channel for brands to promote content and products (Deighton). TikTok, panoramically, is a platform where “playful” user trends— dances, responding to videos, the “Tell Me … Without Telling Me” challenge—occur in the context of an extremely complex algorithm, that while automated, is created by people—and is thus unavoidably embedded with bias (Dias et al.; Noble). This is not to say that game design techniques and broader “playful” design techniques in other digital communication platforms are interchangeable by any measure, or that intent in a game design sense and intent or bias in a commercial sense should be examined through the same lens. Rather that there is a useful, interdisciplinary resource of knowledge that can further illuminate questions we might ask about this state of “ludification” in both the academic and public spheres. We might ask, for example, what would the implications be of introducing an intent design methodology similar to Journey, but using it for commercial gain? Or social activism? Has it already happened? There is a quotation from Nathan Jurgensen’s 2016 essay Fear of Screens (published in The New Inquiry) that often comes to my mind when thinking about interaction design in video games in this way. In his response to Sherry Turkle’s book, Reclaiming Conversation, Jurgensen writes: each time we say “IRL,” “face-to-face,” or “in person” to mean connection without screens, we frame what is “real” or who is a person in terms of their geographic proximity rather than other aspects of closeness — variables like attention, empathy, affect, erotics, all of which can be experienced at a distance. We should not conceptually preclude or discount all the ways intimacy, passion, love, joy, pleasure, closeness, pain, suffering, evil and all the visceral actualities of existence pass through the screen. “Face to face” should mean more than breathing the same air. (Jurgensen) While Jurgensen is not talking about communication in games specifically, there are comparisons to be drawn between his “variables” and “visceral actualities of existence” as the drivers of social meaning-making, and the methodology of games communicating intent and purpose through Swink’s “seemingly arbitrary collection of abstracted variables” (67). When players interact with other characters in a game world (whether they be NPCs or other players), they are inhabiting a shared virtual space, and how designers articulate and present the variables of “closeness”, as Jurgensen defines it, can shape player alignment with the overarching design intent. These design techniques take the place of Jurgensen’s “visceral actualities of existence”. While they may not intrinsically share an overarching purpose, their experiential qualities have the ability to align ethics, priorities, and values between individuals. Interactivity means game design has the potential to facilitate a particular kind of engagement for the player (as demonstrated in Journey) or give opportunities for players to explore a sense of what an emotion might feel like by aligning it with progression or playful activity (as discussed in relation to Transistor). Players may not “feel” exactly what their player-characters do, or care for other characters in the world in the same way a game might encourage them to, but through thoughtful intent design, something of recognition or unity of belief might pass through the screen. References Bogost, Ian. Persuasive Games: The Expressive Power of Video Games. MIT P, 2007. Calleja, Gordon. “Ludic Identities and the Magic Circle.” Playful Identities: The Ludification of Digital Media Cultures. Eds. Valerie Frissen et al. Amsterdam UP, 2015. 211–224. Costikyan, Greg. “I Have No Words & I Must Design: Toward a Critical Vocabulary for Games.” Computer Games and Digital Cultures Conference Proceedings 2002. Ed. Frans Mäyrä. Tampere UP. 9-33. Dias, Avani, et al. “The TikTok Spiral.” ABC News, 26 July 2021. <https://www.abc.net.au/news/2021-07-26/tiktok-algorithm-dangerous-eating-disorder-content-censorship/100277134>. Deighton, Katie. “Animal Crossing Is Emerging as a Media Channel for Brands in Lockdown.” The Drum, 21 Apr. 2020. <https://www.thedrum.com/news/2020/04/21/animal-crossing-emerging-media-channel-brands-lockdown>. Espiritu, Abby. “Japanese Company Attempts to Work Remotely in Animal Crossing: New Horizons.” The Gamer, 29 Mar. 2020. <https://www.thegamer.com/animal-crossing-new-horizons-work-remotely/>. Frissen, Valerie, et al., eds. Playful Identities: The Ludification of Digital Media Cultures. Amsterdam UP, 2015. Garst, Aron. “The Pandemic Canceled Their Wedding. So They Held It in Animal Crossing.” The Washington Post, 2 Apr. 2020. <https://www.washingtonpost.com/video-games/2020/04/02/animal-crossing-wedding-coronavirus/>. Isbister, Katherine. How Games Move Us: Emotion by Design. MIT P, 2016. Journey. thatgamecompany. 2012. Jurgensen, Nathan. “Fear of Screens.” The New Inquiry, 25 Jan. 2016. <https://thenewinquiry.com/fear-of-screens/>. Kasavin, Greg. “Transistor Earns More than 100+ Industry Accolades, Sells More than 600k Copies.” Supergiant Games, 8 Jan. 2015. <https://www.supergiantgames.com/blog/transistor-earns60-industry-accolades-sells-more-than-600k-copies/>. kerode4791. "Wanted to Share My First Experience with the Game, It Was That Awesome.”Reddit, 22 Mar. 2017. <https://www.reddit.com/r/JourneyPS3/comments/60u0am/wanted_to_share_my_f rst_experience_with_the_game/>. Kirkpatrick, Graeme. Aesthetic Theory and the Video Game. Manchester UP, 2011. Noble, Safiya Umoja. Algorithms of Oppression: How Search Engines Reinforce Racism. New York UP, 2018. peace_maybenot. "Wanted to Share My First Experience with the Game, It Was that Awesome” Reddit, 22 Mar. 2017. <https://www.reddit.com/r/JourneyPS3/comments/60u0am/wanted_to_share_my_f rst_experience_with_the_game/>. Petit, Carolyn. “Ghosts in the Machine." Gamespot, 20 May 2014. <https://www.gamespot.com/reviews/transistor-review/1900-6415763/>. Swink, Steve. Game Feel: A Game Designer’s Guide to Virtual Sensation. Amsterdam: Morgan Kaufmann Publishers/Elsevier, 2009. Transistor. Supergiant Games. 2014. Wallace, Kimberley. “The Story behind Supergiant Games’ Transistor.” Gameinformer, 20 May 2021. <https://www.gameinformer.com/2021/05/20/the-story-behind-supergiant-games-transistor>. Webber, Jordan Erica. “The Road to Journey.” Videogames: Design/Play/Disrupt. Eds. Marie Foulston and Kristian Volsing. V&A Publishing, 2018. 14–31.