Distinct Release Profiles Research Articles

Visualization of the degradation of long-acting microneedles and correlation of drug release in vivo based on FRET mechanism

This study introduces a live imaging technique for real-time, non-invasive monitoring of drug release from long-acting microneedles using FRET (Fluorescence Resonance Energy Transfer). Employing Cy5.5 and Cy7 as FRET pairs and levonorgestrel as the model drug, we fabricated microneedles with varying PLGA molecular weights, demonstrating distinct release profiles. The FRET-PLGA-10-MN demonstrated a rapid drug release profile, reaching nearly complete release within a two-day period, while FRET-PLGA-30-MN showed a sustained release over four days. Sensitized Emission FRET (SE-FRET) optimized the imaging process, providing a robust correlation between FRET signals and drug absorption. This method surpasses traditional pharmacokinetic studies by offering a more efficient and comprehensive analysis of microneedle release dynamics in vivo, paving the way for enhanced long-acting microneedle design and therapeutic outcomes. Statement of significance1. FRET technology was applied to microneedle drug delivery system for the first time, which realized real-time, quantitative and non-invasive monitoring of drug release process.2. The long-term microneedle technique was combined with sensitized emission method, and the FRET remaining ratio was innovatively used to investigate the FRET characteristics of microneedles, and the fluorescence ratio of FRET and donor double-channel was quantitatively calculated.3. The correlation between visual fluorescence images of FRET effect and semi-quantitative calculation results based on fluorescence intensity and drug release in vivo with drug-loaded microneedles was analyzed.

Nanofibrous 3D scaffolds capable of individually controlled BMP and FGF release for the regulation of bone regeneration

The current clinical applications of bone morphogenetic proteins (BMPs) are limited to only a few specific indications. Locally controlled delivery of combinations of growth factors can be a promising strategy to improve BMP-based bone repair. However, the success of this approach requires the development of an effective release system and the correct choice of growth factors capable of enhancing BMP activity. Basic fibroblast growth factor (bFGF, also known as FGF-2) has shown promise in promoting bone repair, although conflicting results have been reported. Considering the complex biological activities of FGF-2, we hypothesized that FGF-2 can promote BMP-induced bone regeneration only if the dosage and kinetic parameters of the two factors are individually tailored. In this study, we conducted systematic in vitro studies on cell proliferation, differentiation, and mineralization in response to factor dose, delivery mode (sequential or simultaneous), and release rate. Subsequently, we designed individually controlled BMP-7 and FGF-2 release poly(lactide-co-glycolide) (PLGA) nanospheres attached to the poly(l-lactic acid) (PLLA) nanofibrous scaffolds. The data showed that BMP-7-induced bone formation was accelerated by a relatively higher FGF-2 dose (100 ng/scaffold) delivered at a faster release rate, or by a relatively lower FGF-2 dose (10 ng/scaffold) at a slower release rate in an in vivo bone regeneration model. In contrast, a very high dose of FGF-2 (1000 ng/scaffold) inhibited bone regeneration under all conditions. In vitro and in vivo data suggest that FGF-2 improved BMP-7-induced bone regeneration by coordinating FGF-2 dosage and release kinetics to enhance stem cell migration, proliferation, and angiogenesis. Statement of significanceBone morphogenetic proteins (BMPs) are the most potent growth/differentiation factors in bone development and regeneration. However, the clinical applications of BMPs have been limited to only a few specific indications due to the required supraphysiological dosages with the current BMP products and their side effects. Locally controlled delivery of BMPs and additional growth factors that can enhance their osteogenic potency are highly desired. However, different growth factors act with different mechanisms. Here we report a nanofibrous scaffold that mimics collagen in size and geometry and is immobilized with biodegradable nanospheres to achieve local and distinct release profiles of BMP7 and FGF2. Systematic studies demonstrated low dose BMP7 and FGF2 with different temporal release profiles can optimally enhance bone regeneration.

Grafted sepiolite as smart nanocontainer for Daphne Gnidium plant extract: PH-dependent controlled release and effective green anti-corrosion coating

This study focuses on advancing the development of environmentally sustainable and efficient active anti-corrosion coatings for metal substrates in various engineering applications. A novel smart anti-corrosive container was developed using fibrous sepiolite clay (Sep). Sep was first subjected to grafting with 3-Aminopropyl-diethoxy-methylsilane (APDEMS). Subsequently, the grafted-Sep (Sep-G) was used to load a Daphne Gnidium plant extract (DGE) as a natural corrosion inhibitor. The modification process of Sep was carefully monitored and characterized through Zeta potential, scanning electron microscopy, X-ray diffraction, UV/visible spectroscopy, and Fourier transform infrared spectroscopy. The results highlighted the successful clay modification with a silane loading of 7.68 % and a DGE adsorbed amount of approximately 58 mg/g. The DGE release behavior of the elaborated nanocomposite (Sep-G@DGE) was studied at different pH values and showed distinct pH-dependent release profiles. The rates were in the following order: acidic > alkaline > neutral. Electrochemical properties of Sep-G@DGE were investigated on a bare mild steel electrode in 0.1 M NaCl solution, demonstrating a corrosion inhibition efficiency of 90 % for a 24-hour immersion time at a concentration of 1 g/L. Moreover, the beforehand prepared nanocontainer, Sep-G@DGE, was incorporated into an alkyd resin to formulate a smart anti-corrosion coating. This coating exhibited enhanced anti-corrosion properties and sustained inhibitory effects over time compared to that of a pure alkyd coating. The coating's efficiency is attributable to the high dispersion of the layered clay mineral structure, which allowed an on-demand release of the DGE inhibitor. In addition, the presence of free APDEMS NH3+ group leads to the formation of electrostatic interactions with the adsorbed chloride ions on the metal surface, acting thus as a barrier against corrosive agents and inhibit rust formation in paint cracks.

Ivermectin-Loaded Mesoporous Silica and Polymeric Nanocapsules: Impact on Drug Loading, In Vitro Solubility Enhancement, and Release Performance.

Ivermectin (IVM), a widely used drug for parasitic infections, faces formulation and application challenges due to its poor water solubility and limited bioavailability. Pondering the impact of IVM's high partition coefficient value (log P) on its drug release performance, it is relevant to explore whether IVM nanoencapsulation in organic or inorganic nanoparticles would afford comparable enhanced aqueous solubility. To date, the use of inorganic nanoparticles remains an unexplored approach for delivering IVM. Therefore, here we loaded IVM in mesoporous silica particles (IVM-MCM), as inorganic nanomaterial, and in well-known poly(ε-caprolactone) nanocapsules (IVM-NC). IVM-MCM had a well-organized hexagonal mesoporous structure, reduced surface area, and high drug loading of 10% w/w. IVM-NC had a nanometric mean size (196 nm), high encapsulation efficiency (100%), physicochemical stability as an aqueous dispersion, and drug loading of 0.1% w/w. Despite differing characteristics, both nanoencapsulated forms enhance IVM's aqueous intrinsic solubility compared to a crystalline IVM: after 72 h, IVM-MCM and IVM-NC achieve 72% and 78% releases through a dialysis bag, whereas crystalline IVM dispersion achieves only 40% drug diffusion. These results show distinct controlled release profiles, where IVM-NC provides a deeper sustained controlled release over the whole experiment compared to the inorganic nanomaterial (IVM-MCM). Discussing differences, including drug loading and release kinetics, is crucial for optimizing IVM's therapeutic performance. The study design, combined with administration route plans and safety considerations for humans and animals, may expedite the rational optimization of IVM nanoformulations for swift clinical translation.

Electroactive Polymers for On-Demand Drug Release.

Conductive materials have played a significant role in advancing society into the digital era. Such materials are able to harness the power of electricity and are used to control many aspects of daily life. Conductive polymers (CPs) are an emerging group of polymers that possess metal-like conductivity yet retain desirable polymeric features, such as processability, mechanical properties, and biodegradability. Upon receiving an electrical stimulus, CPs can be tailored to achieve a number of responses, such as harvesting energy and stimulating tissue growth. The recent FDA approval of a CP-based material for a medical device has invigorated their research in healthcare. In drug delivery, CPs can act as electrical switches, drug release is achieved at a flick of a switch, thereby providing unprecedented control over drug release. In this review, recent developments in CP as electroactive polymers for voltage-stimuli responsive drug delivery systems are evaluated. The review demonstrates the distinct drug release profiles achieved by electroactive formulations, and both the precision and ease of stimuli response. This level of dynamism promises to yield "smart medicines" and warrants further research. The review concludes by providing an outlook on electroactive formulations in drug delivery and highlighting their integral roles in healthcare IoT.

Microbe-Mineral Interactions between Asbestos and Thermophilic Chemolithoautotrophic Anaerobes.

The Fe content and the morphometry of asbestos are two major factors linked to its toxicity. This study explored the use of microbe-mineral interactions between asbestos (and asbestos-like) minerals and thermophilic chemolithoautotrophic microorganisms as possible mineral dissolution treatments targeting their toxic properties. The removal of Fe from crocidolite was tested through chemolithoautotrophic Fe(III) reduction activities at 60°C. Chrysotile and tremolite-actinolite were tested for dissolution and potential release of elements like Si and Mg through biosilicification processes at 75°C. Our results show that chemolithoautotrophic Fe(III) reduction activities by Deferrisoma palaeochoriense were supported with crocidolite as the sole source of Fe(III) used as a terminal electron acceptor during respiration. Microbial Fe(III) reduction activities resulted in higher Fe release rates from crocidolite in comparison to previous studies on Fe leaching from crocidolite through Fe assimilation activities by soil fungi. Evidence of biosilicification in Thermovibrio ammonificans did not correspond with increased Si and Mg release from chrysotile or tremolite-actinolite dissolution. However, overall Si and Mg release from chrysotile into our experimental medium outmatched previously reported capabilities for Si and Mg release from chrysotile by fungi. Differences in the profiles of elements released from chrysotile and tremolite-actinolite during microbe-mineral experiments with T. ammonificans underscored the relevance of underlying crystallochemical differences in driving mineral dissolution and elemental bioavailability. Experimental studies targeting the interactions between chemolithoautotrophs and asbestos (or asbestos-like) minerals offer new access to the mechanisms behind crystallochemical mineral alterations and their role in the development of tailored asbestos treatments. IMPORTANCE We explored the potential of chemosynthetic microorganisms growing at high temperatures to induce the release of key elements (mainly iron, silicon, and magnesium) involved in the known toxic properties (iron content and fibrous mineral shapes) of asbestos minerals. We show for the first time that the microbial respiration of iron from amphibole asbestos releases some of the iron contained in the mineral while supporting microbial growth. Another microorganism imposed on the two main types of asbestos minerals (serpentines and amphiboles) resulted in distinct elemental release profiles for each type of asbestos during mineral dissolution. Despite evidence of microbially mediated dissolution in all minerals, none of the microorganisms tested disrupted the structure of the asbestos mineral fibers. Further constraints on the relationships between elemental release rates, amount of starting asbestos, reaction volumes, and incubation times will be required to better compare asbestos dissolution treatments studied to date.

A predictive mechanistic model of drug release from surface eroding polymeric nanoparticles.

Effective drug delivery requires ample dosing at the target tissue while minimizing negative side effects. Drug delivery vehicles such as polymeric nanoparticles (NPs) are often employed to accomplish this challenge. In this work, drug release of numerous drugs from surface eroding polymeric NPs was evaluated in vitro in physiologically relevant pH5 and neutral buffers. NPs were loaded with paclitaxel, rapamycin, resiquimod, or doxorubicin and made from an FDA approved polyanhydride or from acetalated dextran (Ace-DEX), which has tunable degradation rates based on cyclic acetal coverage (CAC). By varying encapsulate, pH condition, and polymer, a range of distinct drug release profiles were achieved. To model the obtained drug release curves, a mechanistic mathematical model was constructed based on drug diffusion and polymer degradation. The resulting diffusion-erosion model accurately described drug release from the variety of surface eroding NPs. For drug release from varied CAC Ace-DEX NPs, the goodness of fit of the developed diffusion-erosion model was compared to several conventional drug release models. The diffusion-erosion model maintained optimal fit compared to conventional models across a range of conditions. Machine learning was then employed to estimate effective diffusion coefficients for the diffusion-erosion model, resulting in accurate prediction of in vitro release of dexamethasone and 3'3'-cyclic guanosine monophosphate-adenosine monophosphate from Ace-DEX NPs. This predictive modeling has potential to aid in the design of future Ace-DEX formulations where optimized drug release kinetics can lead to a desired therapeutic effect.

Modelling intramuscular drug fate in vitro with tissue-relevant biomimetic hydrogels

Parenteral administrations are a mainstay of clinical drug delivery. Intramuscular (IM) injections deposit drug directly into skeletal muscle bellies, providing rapid systemic uptake due to the highly vascularized nature of this site. The potential to inject particulate or non-aqueous materials have also made IM injections useful for long-acting formulations. These attributes have supported a plethora of medicines being approved for IM administration. Despite these many approvals across multiple pharmaceutical categories, mechanisms that control drug release from the injection site, and thus its pharmacokinetic properties, remain poorly understood. Several pre-clinical in vivo animals have been used to model IM drug fate in patients, but these approaches have not consistently predicted clinical outcomes. This lack of a predictive in vivo model and no standardized in vitro tools have limited the options of pharmaceutical scientists to rationally design formulations for IM delivery. Here, we describe a novel, tractable in vitro model informed by dominant extracellular matrix (ECM) components present at the IM injection site. Three charge variants of green florescent protein (GFP) and the impact of three common formulation components were examined in an initial test of this in vitro model. A strongly positively charged GFP was restricted in its release from hydrogels composed of ECM components type I collagen and hyaluronic acid compared to standard and strongly negatively charged GFP. Introduction of commonly used buffers (histidine or acetate) or the non-ionic surfactant polysorbate 20 altered the release properties of these GFP variants in a manner that was dependent upon ECM element composition. In sum, this Simulator of IntraMuscular Injections, termed SIMI, demonstrated distinct release profiles of a protein biopharmaceutical surrogate that could be exploited to interrogate the impact of formulation components to expedite novel drug development and reduce current dependence on potentially non-predictive pre-clinical in vivo models.

Fabrication and Modelling of a Reservoir-Based Drug Delivery System for Customizable Release.

Localized therapy approaches have emerged as an alternative drug administration route to overcome the limitations of systemic therapies, such as the crossing of the blood–brain barrier in the case of brain tumor treatment. For this, implantable drug delivery systems (DDS) have been developed and extensively researched. However, to achieve an effective localized treatment, the release kinetics of DDS needs to be controlled in a defined manner, so that the concentration at the tumor site is within the therapeutic window. Thus, a DDS, with patient-specific release kinetics, is crucial for the improvement of therapy. Here, we present a computationally supported reservoir-based DDS (rDDS) development towards patient-specific release kinetics. The rDDS consists of a reservoir surrounded by a polydimethylsiloxane (PDMS) microchannel membrane. By tailoring the rDDS, in terms of membrane porosity, geometry, and drug concentration, the release profiles can be precisely adapted, with respect to the maximum concentration, release rate, and release time. The release is investigated using a model dye for varying parameters, leading to different distinct release profiles, with a maximum release of up to 60 days. Finally, a computational simulation, considering exemplary in vivo conditions (e.g., exchange of cerebrospinal fluid), is used to study the resulting drug release profiles, demonstrating the customizability of the system. The establishment of a computationally supported workflow, for development towards a patient-specific rDDS, in combination with the transfer to suitable drugs, could significantly improve the efficacy of localized therapy approaches.

A Modular Composite Device of Poly(Ethylene Oxide)/Poly(Butylene Terephthalate) (PEOT/PBT) Nanofibers and Gelatin as a Dual Drug Delivery System for Local Therapy of Soft Tissue Tumors.

In the clinical management of solid tumors, the possibility to successfully couple the regeneration of injured tissues with the elimination of residual tumor cells left after surgery could open doors to new therapeutic strategies. In this work, we present a composite hydrogel–electrospun nanofiber scaffold, showing a modular architecture for the delivery of two pharmaceutics with distinct release profiles, that is potentially suitable for local therapy and post-surgical treatment of solid soft tumors. The composite was obtained by coupling gelatin hydrogels to poly(ethylene oxide)/poly(butylene terephthalate) block copolymer nanofibers. Results of the scaffolds’ characterization, together with the analysis of gelatin and drug release kinetics, displayed the possibility to modulate the device architecture to control the release kinetics of the drugs, also providing evidence of their activity. In vitro analyses were also performed using a human epithelioid sarcoma cell line. Furthermore, publicly available expression datasets were interrogated. Confocal imaging showcased the nontoxicity of these devices in vitro. ELISA assays confirmed a modulation of IL-10 inflammation-related cytokine supporting the role of this device in tissue repair. In silico analysis confirmed the role of IL-10 in solid tumors including 262 patients affected by sarcoma as a negative prognostic marker for overall survival. In conclusion, the developed modular composite device may provide a key-enabling technology for the treatment of soft tissue sarcoma.

Proniosomal vesicles as an effective strategy to optimize naproxen transdermal delivery

The oral administration of naproxen, a non-steroidal analgesic, antipyretic, anti-inflammatory drug, is associated with various gastrointestinal side effects including peptic ulcer and gastritis. The objective of the present research was to evaluate the prospective of transdermal delivery of naproxen using proniosomes as a vesicular carrier and its comparison with oral therapy. Drug loaded proniosomes were prepared by coacervation phase separation, which comprising of spans/tweens, lecithin, and cholesterol. The influence of formulation components was evaluated to assess their impact on the entrapment efficiency, vesicle size, zeta potential, in vitro release and ex vivo permeation. The results signify that the type of surfactant influenced the entrapment efficiency, vesicle size and zeta potential values of prepared proniosomes. All formulations displayed nano-sized vesicles with small polydispersity index value showing narrow particle size distribution. Hydrophilic tweens produced larger vesicles and exhibited greater drug release than their hydrophobic spans counterparts. Prepared proniosomes exhibited distinct drug release profile (p < 0.05) as compared to control HPMC hydrogel. The proniosomal formulation (F3) containing span 60 showed superior transdermal flux (1.10 ± 0.24 μg cm−2 h−1) when compared to other non-ionic surfactants tested. In vivo data demonstrated both anti-inflammatory and antinociceptive efficiency of transdermal naproxen proniosome formulation (F3) was equivalent to the oral marketed naproxen tablets at same dose. Overall the results of present investigation suggest that proniosomes can be considered as a practicable and feasible alternative for oral naproxen delivery.

Development of a 3D Bioprinted Scaffold with Spatio-temporally Defined Patterns of BMP-2 and VEGF for the Regeneration of Large Bone Defects.

The local delivery of growth factors such as BMP-2 is a well-established strategy for the repair of bone defects. The limitations of such approaches clinically are well documented and can be linked to the need for supraphysiological doses and poor spatio-temporal control of growth factor release in vivo. Using bioprinting techniques, it is possible to generate implants that can deliver cytokines or growth factors with distinct spatiotemporal release profiles and patterns to enhance bone regeneration. Specifically, for bone healing, several growth factors, including vascular endothelial growth factor (VEGF) and bone morphogenic proteins (BMPs), have been shown to be expressed at different phases of the process. This protocol aims to outline how to use bioprinting strategies to deliver growth factors, both alone or in combination, to the site of injury at physiologically relevant dosages such that repair is induced without adverse effects. Here we describe: the printing parameters to generate the polymer mechanical backbone; instructions to generate the different bioinks and allow for the temporal control of both growth factors; and the printing process to develop implants with spatially defined patterns of growth factors for bone regeneration. The novelty of this protocol is the use of multiple-tool fabrication techniques to develop an implant with spatio-temporal control of growth factor delivery for bone regeneration. While the overall aim of this protocol was to develop an implant for bone regeneration, the technique can be modified and used for a variety of regenerative purposes. Graphic abstract: 3D Bioprinting Spatio-Temporally Defined Patterns of Growth Factors to Tightly Control Bone Tissue Regeneration.

Controlled Delivery of Immunomodulators from a Biomaterial Scaffold Niche to Induce a Tolerogenic Phenotype in Human Dendritic Cells.

Engineering a regulatory phenotype in dendritic cells (DCs) is a potential approach to circumvent an immune response against self-antigens in autoimmunity or alloantigens in allograft rejection. Cell microenvironments influence the differentiation of DC precursors into either proinflammatory/immunostimulatory or tolerogenic/regulatory DCs. Biomaterial-based vehicles can be used to re-engineer cell microenvironments and re-educate the DC phenotype. This study presents the development and validation of a biomaterial-based multicomponent immunomodulatory (MI) scaffold for the purpose of promoting a tolerogenic/regulatory DC phenotype. Glutaraldehyde-crosslinked gelatin microparticles, loaded with specific immunomodulators, were embedded into a porous agarose scaffold. Using the Weibull equation and the Bayesian approach, an empirical mathematical model was derived from the release profile data of "model" molecules. The scaffold design was generated from the model to achieve distinct temporal release profiles of the loaded immunomodulator(s): granulocyte monocyte colony-stimulating factor (GM-CSF), dexamethasone (DEX), and/or peptidoglycan (PGN). The MI scaffold-treated DCs (MI DCs) showed an increase in the expression of tolerogenic markers such as surface immunoglobulin-like transcript 3 (ILT-3) and secreted interleukin-10 (IL-10), with a simultaneous decrease in maturation markers such as CD86 and secreted interferon-γ (IFN-γ). In cell culture studies, these MI DCs were able to suppress T-cell proliferation. This approach is expected to enhance the generation of endogenous regulatory DCs when applied in vivo. This technology serves as a basis for future immunotherapeutic applications in the autoimmunity and allogeneic therapies. It also shows that empirical mathematical modeling can be used to engineer scaffold designs for distinct temporal release of one or more immunomodulators.

The Release of the Bromodomain Ligand N,N-Dimethylacetamide Adds Bioactivity to a Resorbable Guided Bone Regeneration Membrane in a Rabbit Calvarial Defect Model.

N,N-Dimethylacetamide (DMA) is FDA approved as an excipient and is used as drug-delivery vehicle. Due to its amphipathic nature and diverse bioactivities, it appears to be a good combination of biodegradable poly-lactide-co-glycolide (PLGA)-based guided bone regeneration membranes. Here we show that the solvent DMA can be loaded to PLGA membranes by different regimes, leading to distinct release profiles, and enhancing the bone regeneration in vivo. Our results highlight the potential therapeutic benefits of DMA in guided bone regeneration procedures, in combination with biodegradable PLGA membranes.

Phase dependent encapsulation and release profile of ZIF-based biocomposites.

Biocomposites composed of Zeolitic Imidazolate Frameworks (ZIFs) are generating significant interest due to their facile synthesis, and capacity to protect proteins from harsh environments. Here we systematically varied the composition (i.e. relative amounts of ligand (2-methylimidazole), metal precursor (Zn(OAc)2·2H2O), and protein) and post synthetic treatments (i.e. washes with water or water/ethanol) to prepare a series of protein@ZIF biocomposites. These data were used to construct two ternary phase diagrams that showed the synthesis conditions employed gave rise to five different phases including, for the first time, biocomposites based on ZIF-CO3-1. We examined the influence of the different phases on two properties relevant to drug delivery applications: encapsulation efficiency and release profile. The encapsulation efficiencies of bovine serum albumin and insulin were phase dependent and ranged from 75% to 100%. In addition, release profiles showed that 100% protein release varied between 40 and 300 minutes depending on the phase. This study provides a detailed compositional map for the targeted preparation of ZIF-based biocomposites of specific phases and a tool for the straightforward analysis of the crystalline phases of ZIF based materials (web application named “ZIF phase analysis”). These data will facilitate the progress of ZIF bio-composites in the fields of biomedicine and biotechnology.

Pendant Functionalized Polyester Nanofibers with Dual Cargo Release.

Common polymeric biomaterials lack the ability to control the release of multiple bioactive compounds due to their inherent lack of functionality. These materials often require additional components or complicated fabrication techniques to achieve the separate release profiles desired for wound healing and tissue engineering applications. This prevents many biomaterials from being translated to the clinic, because the complexity of the wound environment necessitates temporal control of multiple additives for effective healing. Electrospun nanofibers comprised of a functional polymer would allow for separate release profiles of multiple bioactive compounds through covalent conjugation or tuning noncovalent interactions. In this work, two fluorescent dyes as model drugs were released from functional polyester electrospun mats. Two mats were fabricated: one in which both dyes were blended into the electrospinning solution and one in which one dye was blended and the other was covalently conjugated to the polymer. Average fiber diameters were determined using scanning electron microscopy, while fluorescence microscopy showed the presence of both dyes in the fibers. Dye release was tracked using UV-vis spectroscopy by comparing measured values to standard curves. Finally, degradation of the mats was tracked using gel permeation chromatography. With this functional polyester platform, distinct release profiles were achieved for two model drugs. Not only does the release of two model drugs show potential for the future use of this polymer platform in the applications of wound healing and tissue engineering but also the ability to incorporate several distinct conjugation chemistries is of great benefit.

Multi-drug hybrid delivery systems with distinct release profiles based on gelatin/collagen containing vesicles derived from block copolymers

Hybrid delivery systems can release multiple drugs with different profiles and have several applications, including skin dressing. In this work, the co-solvent technique was used for the preparation of nanometric vesicles based on poly(styrene-b-ethylene oxide) block copolymer (BCPVs) containing adapalene (AD). The BCPVs were incorporated into collagen and gelatin matrices together with free AD and silver sulfadiazine (SSD). The AD content of BCPVs and their release capacity were analyzed by using ultraviolet-visible spectroscopy (UV–Vis). The gelatin and collagen matrices were evaluated for their ability to release AD and SSD through an in vitro release study. The obtained results confirmed that the production of empty and AD-loaded BCPVs was viable. The degree of AD encapsulation in BCPVs was 9.0% and the in vitro test revealed a constant, slow, and prolonged release of AD content from AD-loaded BCPVs. The combination of free and encapsulated multiple drugs in hybrid delivery systems based on gelatin and collagen matrices was shown to act as a skin dressing that combined the progressive release of large amounts of drugs within the first hours of use (to restrict infection) with a more prolonged and slow release of AD to enhance skin healing.

Abstract 4990: An in vivo method for determining cancer immunotherapy induced cytokine release syndrome utilizing PBMC humanized mice

Abstract Monoclonal antibodies (mAbs), as either single agents or in combination, have shown remarkable efficacy for cancer immunotherapy. However the use of antibody-based immunotherapies can result in the development of severe adverse effects for many patients, including cytokine release syndrome (CRS). Two methodologies used routinely for CRS drug toxicity testing are in vitro assays with human PBMC and in vivo testing in animal models. Unfortunately, neither method reliably predicts the immune toxicity in humans. For example, in vitro testing does not mimic the complexities of the biological environment in humans, and testing of human-specific agents in either rodent or non-human primates is limited by the many species-specific differences in immune system function. This significant gap between pre-clinical testing of novel therapeutics and clinical trials demonstrates a critical need for translational protocols that more accurately predict immune toxicity. We have developed a novel humanized mouse model for testing CRS that is rapid, sensitive and reproducible. This model is based on human PBMC engraftment of NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ (NSG; JAX stock number 005557) mice, and assessment of CRS is performed within 6 days of PBMC injection. Within 6 days of PBMC injection, total human immune cell (CD45+) levels averaged 10 to 15% of cells in blood with approximately 70% and 25% of the human CD45+ cells being CD3+ T cells or CD56+ NK cells, respectively. To validate this model, PBMC-engrafted NSG mice were challenged with OKT3 (anti-CD3) by day 6 after PBMC injection, which is a timepoint prior to the development of robust xenogeneic GVHD. Severe clinical symptoms developed rapidly in OKT3-treated mice, including production of human cytokines and a significant drop in body temperature as compared to control PBS-treated mice. Using our validated humanized mouse model, induction of CRS was tested using clinically relevant mAb as either single agents, including pembrolizumab, anti-CD28, and ATG (anti-thymocyte globulin). We observed robust clinical readouts for these mAb treatments, with induction of rapid and distinct cytokine release profiles. Moreover our assay also identified donors that were “high” responders and “low” responders to specific mAb treatments. A direct comparison of our humanized mouse model to an in vitro based PBMC assay revealed several advantages for the humanized assay, including higher sensitivity and more accurate recapitulation of clinical observations. Notably our humanized mouse model also demonstrated utility when evaluating combination therapies, including pembrolizumab/lenalidomide, pembrolizumab/ATG, and anti-CD28/ATG and enabled the identification of unique patterns of CRS. In conclusion, we have developed a translational humanized mouse model for preclinical assessment of CRS adverse events to mAb therapeutics. Citation Format: Chunting Ye, Mingshan Cheng, Michael Brehm, Dale Greiner, Leonard Shultz, James G. Keck. An in vivo method for determining cancer immunotherapy induced cytokine release syndrome utilizing PBMC humanized mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4990.

Natural polyelectrolyte complex‐based pH‐dependent delivery carriers using alginate and chitosan

ABSTRACTThe pH‐dependent complexation behaviors of natural and counterionic polyelectrolyte complexes (PECs) without crosslinkers have been rarely studied. In this work, alginate (0.5–2.5 wt %) and chitosan (0.5–2 wt %) were combined to formulate turbid gel‐like assemblies. The PEC was consisted of ~100‐μm‐sized porous structure observed by scanning electron microscope images and electrostatic interactions inside the complex were newly formed characterized by Fourier transform infrared spectra. Based on visual monitoring and ultraviolet–visible absorption measurement, the complex maintained the gel‐like structure under acidic, while the complex was more dissolved under becoming basic. As a demonstration of potential pH‐dependent delivery, distinct release profiles of the complexes encapsulating rhodamine 6G (R6G) or doxorubicin, were observed when they were immersed in acidic, neutral, and basic medium. Within 2 h, 7.4, 35.4, and 73.7% of R6G were released under acidic, neutral, and basic condition, respectively, with reasons of degree of protonation or deprotonation of each natural polyelectrolyte at certain pH. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48143.

3D Printing of a Multi-Layered Polypill Containing Six Drugs Using a Novel Stereolithographic Method.

Three-dimensional printing (3DP) has demonstrated great potential for multi-material fabrication because of its capability for printing bespoke and spatially separated material conformations. Such a concept could revolutionise the pharmaceutical industry, enabling the production of personalised, multi-layered drug products on demand. Here, we developed a novel stereolithographic (SLA) 3D printing method that, for the first time, can be used to fabricate multi-layer constructs (polypills) with variable drug content and/or shape. Using this technique, six drugs, including paracetamol, caffeine, naproxen, chloramphenicol, prednisolone and aspirin, were printed with different geometries and material compositions. Drug distribution was visualised using Raman microscopy, which showed that whilst separate layers were successfully printed, several of the drugs diffused across the layers depending on their amorphous or crystalline phase. The printed constructs demonstrated excellent physical properties and the different material inclusions enabled distinct drug release profiles of the six actives within dissolution tests. For the first time, this paper demonstrates the feasibility of SLA printing as an innovative platform for multi-drug therapy production, facilitating a new era of personalised polypills.