Use of Polyvinyl Alcohol as a Solubility-Enhancing Polymer for Poorly Water Soluble Drug Delivery (Part 1)

Microfluidic nanoparticle synthesis for oral solid dosage forms: A step toward clinical transition processes

Nanomedicine provides various opportunities for addressing medical challenges associated with drug bioavailability, stability, and efficacy. In particular, oral nanoparticles (NPs) represent an alternative strategy to enhance the solubility and stability of active ingredients through the gastrointestinal tract. The nanocarriers could be used for both local and systemic targeting, enabling controlled release of encapsulated drugs. This approach allows more efficient therapies. In this work, we aim to develop reliable oral solid dosage forms incorporating NPs produced by either one pot synthesis or continuous production, following protocols that yield highly consistent outcomes, promoting their technology transfer and clinical use. Microfluidics technology was selected to allow an automated and highly productive synthetic approach suitable for the highly throughput production. In particular, innovative systems, which combine advantage of NPs and solid dosage formulation, were designed, developed, and characterized demonstrating the possibility to obtaining oral administration. The resulting NPs were thus carried on oral dosage forms, i.e., pellets and minitablets. NPs resulted stable after dosage forms manufacturing, leading to confidence also on protection of encapsulated drugs. Indomethacin was used as a tracer to test biopharmaceutical behaviour. Anti-inflammatories or cytotoxic chemotherapeutics could be vehiculated leading to a breakthrough in the treatment of severe diseases allowing the oral administration of these drugs. We believe that the advancement achieved with the results of our work paves the way for the progression of nanoproducts into clinical transition processes.

Development of Ethylcellulose Microparticles for Taste Masking of Fexofenadine

For taste masking of fexofenadine hydrochloride (FXD), ethylcellulose (EC) microparticles with FXD were developed. The amounts of EC, Tween 80, and polyvinyl alcohol (PVA) in the composition had little effect on initial drug release properties. Based on the results of the drug recovery and the drug release properties, FXD(EC200) was the optimal FXD microparticle formulation. From the results of Fourier transform infrared spectroscopy spectra and X-ray diffraction patterns of FXD(EC200), FXD amorphization in the microparticles and interaction between FXD and other components were suggested, and the formation of a solid dispersion of FXD was suggested. Because the possibility of the complex of PVA and FXD on the particle surface was suggested, sodium lauryl sulfate (SLS) was added to the composition. The initial drug release from FXD microparticles with SLS was further suppressed compared with FXD(EC200). From these results, FXD microparticles with SLS can be prepared as a controlled-release formulation and are expected to be useful for masking the bitter tasting particulates.

Polyvinyl alcohol coating releasing fungal blastospores improves kill effect of attract-and-kill beads

Polyvinyl alcohol (PVA) is a biodegradable, water-soluble polymer with excellent film forming properties, commonly studied or used as tablet coating, food packaging or controlled release fertilizers. Attract-and-kill (AK) beads are sustainable, microbial alternatives to synthetic soil insecticides, whose onset of lethal effect largely depend on how fast the encapsulated entomopathogenic fungus forms virulent conidia. Therefore, the objective of this study was to develop a water-soluble coating accelerating the kill effect of AK beads by immediately releasing virulent Metarhizium brunneum CB15-III blastospores. We assessed three PVA types (PVA 4-88, 8-88, 10-98) which differed in their degree of hydrolysis or molecular weight for their ability to release viable blastospores from thin films after drying at 60-40 °C, and examined how polyethylene glycol and soy-lecithin impact the blastospore survival. Finally, we evaluated the effectiveness of coated AK beads in a bioassay against Tenebrio molitor larvae. The blastospore release rate quadrupled within the first 5 min with decreasing molecular weight and degree of hydrolysis, with PVA 4-88 releasing 79 ± 19% blastospores. Polyethylene glycol and soy-lecithin significantly increased the blastospore survival to 18-28% for all three PVA types. Coated beads exhibited a uniform, 22.4 ± 7.3 µm thin coating layer, with embedded blastospores, as confirmed by scanning electron microscopy. The blastospore coating increased the mortality rate of T. molitor larvae over uncoated AK beads, decreasing the median lethal time from 10 to 6 days. Consequently, the blastospore coating accelerated the kill effect of regular AK beads. These findings pave the way to enhanced pest control efficacy from coated systems such as beads or seeds.

Study and Characterization of Polyvinyl Alcohol-Based Formulations for 3D Printlets Obtained via Fused Deposition Modeling

Three-dimensional (3D) printing has emerged as a new promising technique for the production of personalized dosage forms and medical devices. Polyvinyl alcohol is prominently used as a source material to produce 3D-printed medicines via fused deposition modeling (FDM)-a technology that combines hot melt extrusion and 3D printing. A preliminary screening of three grades of PVA indicated that partially hydrolyzed PVA with a molecular weight (MW) of 31,000-50,000 and plasticized with sorbitol was most suitable for 3D printing. Paracetamol was used as a model drug. The materials and the produced filaments were characterized by X-ray powder diffraction (XRPD), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The complex viscosity (η*) of the polymer melts was determined as a function of the angular frequency (ω) at the printing temperature to assess their printability. Three-dimensional printlets with a 40% infill exhibited an immediate release of the API, while tablets with a higher infill were prone to a prolonged release regardless of the filament drug loading. A factorial design was used to give more insight into the influence of the drug-loading of the filaments and the tablet infill as independent variables on the production of 3D printlets. The Pareto chart confirmed that the infill had a statistically significant effect on the dissolution rate after 45 min, which was chosen as the response variable.

A Review on Physicochemical Properties of Polymers Used as Filaments in 3D-Printed Tablets

Three-dimensional (3D) printing technology has presently been explored widely in the field of pharmaceutical research to produce various conventional as well as novel dosage forms such as tablets, capsules, oral films, pellets, subcutaneous implants, scaffolds, and vaginal rings. The use of this innovative method is a good choice for its advanced technologies and the ability to make tailored medicine specifically for individual patient. There are many 3D printing systems that are used to print tablets, implants, and vaginal rings. Among the available systems, the fused deposition modeling (FDM) is widely utilized. The FDM has been regarded as the best choice of printer as it shows high potential in the production of tablets as a unit dose in 3D printing medicine manufacturing. In order to design a 3D-printed tablet or other dosage forms, the physicochemical properties of polymers play a vital role. One should have proper knowledge about the polymer's properties so that one can select appropriate polymers in order to design 3D-printed dosage form. This review highlighted the various physicochemical properties of polymers that are currently used as filaments in 3D printing. In this manuscript, the authors also discussed various systems that are currently adopted in the 3D printing.

Pre-Processing a Polymer Blend into a Polymer Alloy by KinetiSol Enables Increased Ivacaftor Amorphous Solid Dispersion Drug Loading and Dissolution

This study compares the effects of pre-processing multiple polymers together to form a single-phase polymer alloy prior to amorphous solid dispersion formulation. KinetiSol compounding was used to pre-process a 1:1 (w/w) ratio of hypromellose acetate succinate and povidone to form a single-phase polymer alloy with unique properties. Ivacaftor amorphous solid dispersions comprising either a polymer, an unprocessed polymer blend, or the polymer alloy were processed by KinetiSol and examined for amorphicity, dissolution performance, physical stability, and molecular interactions. A polymer alloy ivacaftor solid dispersion with a drug loading of 50% w/w was feasible versus 40% for the other compositions. Dissolution in fasted simulated intestinal fluid revealed that the 40% ivacaftor polymer alloy solid dispersion reached a concentration of 595 µg/mL after 6 h, 33% greater than the equivalent polymer blend dispersion. Fourier transform infrared spectroscopy and solid-state nuclear magnetic resonance revealed changes in the ability of the povidone contained in the polymer alloy to hydrogen bond with the ivacaftor phenolic moiety, explaining the differences in the dissolution performance. This work demonstrates that the creation of polymer alloys from polymer blends is a promising technique that provides the ability to tailor properties of a polymer alloy to maximize the drug loading, dissolution performance, and stability of an ASD.

Metabolite-induced in vivo fabrication of substrate-free organic bioelectronics

Interfacing electronics with neural tissue is crucial for understanding complex biological functions, but conventional bioelectronics consist of rigid electrodes fundamentally incompatible with living systems. The difference between static solid-state electronics and dynamic biological matter makes seamless integration of the two challenging. To address this incompatibility, we developed a method to dynamically create soft substrate-free conducting materials within the biological environment. We demonstrate in vivo electrode formation in zebrafish and leech models, using endogenous metabolites to trigger enzymatic polymerization of organic precursors within an injectable gel, thereby forming conducting polymer gels with long-range conductivity. This approach can be used to target specific biological substructures and is suitable for nerve stimulation, paving the way for fully integrated, in vivo-fabricated electronics within the nervous system.

A Critical Review on the Feasibility of Synthetic Polymers Inclusion in Enhancing the Geotechnical Behavior of Soils

Polymers have attracted widespread interest as soil stabilizers and are proposed as an ecologically acceptable means for enhancing the geotechnical properties of soils. They have found profound applications in diverse fields such as the food industry, textile, medicine, agriculture, construction, and many more. Various polymers are proven to increase soil shear strength, improve volume stability, promote water retention, and prevent erosion, at extremely low concentrations within soils through the formation of a polymer membrane around the soil particles upon hydration. The purpose of this work is to provide an overview of existing research on synthetic polymers for soil improvement. A fundamental evaluation of many synthetic polymers used in soil stabilization is provided, Furthermore, the impact of different polymer types on the geotechnical parameters of treated soil was assessed and compared. Limiting factors like polymer durability and the effect of changing climatic conditions on the engineering behavior of the polymer-treated soils have been critically reviewed. The dominant mechanisms responsible for the alteration in the behavior of polymer-soil admixture are reviewed and discussed. This review article will allow practicing engineers to better understand the intrinsic and extrinsic parameters of targeted polymers before employing them in real-field scenarios for better long-term performance.

The role of hydrophilic/hydrophobic group ratio of polyvinyl alcohol on the miscibility of amlodipine in orodispersible films: From molecular mechanism study to product attributes

The miscibility of the therapeutic drug in the polymer matrix is the key to the successful design and development of orodispersible films (ODFs). In the present study, four hydrolyzed polyvinyl alcohols (PVAs) with identical polymerization degree were investigated as carriers for Amlodipine (AML) ODFs systematically. The drug-polymer miscibility and the intermolecular interaction were investigated by Flory-Huggins theory, Gordon-Taylor theory, molecular simulation, FTIR, Raman and ¹H NMR. The product attributes of ODFs were also studied. A pharmacokinetic study in rats was then conducted using the film product of PVA5-72, the best performer tested. The results revealed that the drug-polymer miscibility decreased linearly with the increase of hydrolyzed degree of PVA. Hydrogen bonds formed between the drug and the hydrophilic and hydrophobic groups of PVAs were the main intermolecular interaction that caused the differences in drug-polymer miscibility. Furthermore, drug-polymer interaction influenced the product attributes of ODFs, including dissolution profile, mechanical properties and physical stability. The pharmacokinetic study showed the ODFs disintegrated rapidly, and the amorphous AML dissolved and absorbed in the gastrointestinal tract, which was comparable to the commercial product. The research offered a foundation for development scientists in designing and formulating PVA films.

Rivaroxaban lyospheres prepared by a dimethyl sulfoxide-based spray-freeze-drying process

Spray-freeze-drying (SFD) processes are usually using aqueous solvent systems, which however, exclude the use of SFD for poorly water-soluble drugs. Here, we evaluated dimethyl sulfoxide for its suitability in formulating SFD particles (lyospheres®). Rivaroxaban was spray-freeze-dried from DMSO solutions containing polyvinyl pyrrolidone (PVP; Kollidon® 25), vinylpyrrolidone-vinyl acetate copolymer (PVP-VA; Kollidon® VA64) or polyvinyl alcohol 4-88 (PVA) forming porous lyospheres® (median particle size 250 to 350 µm). Rivaroxaban was amorphous with all three polymers, which in combination with their high porosity resulted in rapid dissolution in vitro within 10 minutes. Consequently, this translated in lower T_max (0.5-1.0 hour) after oral administration of lyospheres® to rats (compared with T_max of 4 hours with coarse rivaroxaban). Lyosphere formulations achieved a distinct bioavailability increase (AUC_(0-inf) = 1487±657 ng*h/ml with PVP; 4426±1553 ng*h/ml with PVP-VA; 9569±3868 ng*h/ml with PVA lyospheres®; whereas 385±145 ng*h/ml with coarse rivaroxaban). These in vitro and in vivo results underlined the benefit of using DMSO in SFD that can broaden the applicability of the SFD process to much a larger repertoire of poorly water-soluble drugs.

Melt Fusion Techniques for Solubility Enhancement: A Comparison of Hot Melt Extrusion and KinetiSol® Technologies

A successful candidate for oral drug delivery needs to possess adequate solubility and dissolution rate to elicit its therapeutic action. Extensive research is being carried out to enhance the solubility of poorly soluble drugs through a number of techniques involving polymeric and non-polymeric approaches. Non-polymeric approaches such as micronization and nanocrystals are successful in improving the apparent solubility of drugs, but the sustenance of solubility is not always possible. Amorphous solid dispersions (ASDs) lead to solubility enhancement as well as the maintenance of solubility with the assistance of polymers, thereby improving bioavailability. Spray drying, hot melt extrusion (HME), and KinetiSol® technologies are some of the techniques capable of manufacturing ASDs. Each of these techniques has its own advantages and disadvantages in terms of processing challenges and applicability in preparing ASDs. The latter two technologies are similar in being fusion and non-solvent techniques to improve solubility. This review compares both HME and KinetiSol® techniques regarding mechanism, equipment design, formulation, and process parameters involved and scalability.

A Naked Eye-Invisible Ratiometric Fluorescent Microneedle Tattoo for Real-Time Monitoring of Inflammatory Skin Conditions

The field of portable healthcare monitoring devices has an urgent need for the development of real-time, noninvasive sensing and detection methods for various physiological analytes. Currently, transdermal sensing techniques are severely limited in scope (i.e., measurement of heart rate or sweat composition), or else tend to be invasive, often needing to be performed in a clinical setting. This study proposes a minimally invasive alternative strategy, consisting of using dissolving polymeric microneedles to deliver naked eye-invisible functional fluorescent ratiometric microneedle tattoos directly to the skin for real-time monitoring and quantification of physiological and pathological parameters. Reactive oxygen species are overexpressed in the skin in association with various pathological conditions. Here, one demonstrates for the first time the microneedle-based delivery to the skin of active fluorescent sensors in the form of an invisible, ratiometric microneedle tattoo capable of sensing reactive oxygen species in a reconstructed human-based skin disease model, as well as an in vivo model of UV-induced dermal inflammation. One also elaborates a universal ratiometric quantification concept coupled with a custom-built, multiwavelength portable fluorescence detection system. Fully realized, this approach presents an opportunity for the minimally invasive monitoring of a broad range of physiological parameters through the skin.

Development, characterization, and in vitro evaluation of adhesive fibrous mat for mucosal propranolol delivery

This research focuses on the synthesis and adhesive properties of mucoadhesive mats, prepared with poly(vinylic alcohol) as a base polymer for the oromucosal release of propranolol (PRO) by the electrospinning technique. The nanofibers mats were evaluated by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy, thermogravimetric analysis, and differential scanning calorimetry; in vitro drug entrapment efficiency, degradation time, and adhesion studies were performed. SEM images of the electrospun mats show the correct formation of fibers with a variable diameter and porosity. Thermal studies indicate excellent thermal stability of the scaffolds, The fibrous mats loaded with 10% of the drug exhibit the best thermal stability with decomposition after 450°C. In vitro studies indicate a drug content of 88% loaded in the mats. In the cytotoxicity test, loaded mat presents cell proliferations of 97% and 88% for drug concentrations of 10% an 15%, respectively. To conclude, the formed electrospun adhesive mats exhibited excellent thermal stability, adhesive properties, and drug entrapment efficiency, promising features for a successful drug topical release system on mucosal tissue in the oral cavity.

Improved Bioavailability of Poorly Water-Soluble Drug by Targeting Increased Absorption through Solubility Enhancement and Precipitation Inhibition

Itraconazole (ITZ) is a class II drug according to the biopharmaceutical classification system. Its solubility is pH 3-dependent, and it is poorly water-soluble. Its pKa is 3.7, which makes it a weak base drug. The aim of this study was to prepare solid dispersion (SD) pellets to enhance the release of ITZ into the gastrointestinal environment using hot-melt extrusion (HME) technology and a pelletizer. The pellets were then filled into capsules and evaluated in vitro and in vivo. The ITZ changed from a crystalline state to an amorphous state during the HME process, as determined using DSC and PXRD. In addition, its release into the gastrointestinal tract was enhanced, as was the level of ITZ recrystallization, which was lower than the marketed drug (Sporanox^®), as assessed using an in vitro method. In the in vivo study that was carried out in rats, the AUC_0-48h of the commercial formulation, Sporanox^®, was 1073.9 ± 314.7 ng·h·mL^-1, and the bioavailability of the SD pellet (2969.7 ± 720.6 ng·h·mL^-1) was three-fold higher than that of Sporanox^® (*** p < 0.001). The results of the in vivo test in beagle dogs revealed that the AUC_0-24h of the SD-1 pellet (which was designed to enhance drug release into gastric fluids) was 3.37 ± 3.28 μg·h·mL^-1 and that of the SD-2 pellet (which was designed to enhance drug release in intestinal fluids) was 7.50 ± 4.50 μg·h·mL^-1. The AUC of the SD-2 pellet was 2.2 times higher than that of the SD-1 pellet. Based on pharmacokinetic data, ITZ would exist in a supersaturated state in the area of drug absorption. These results indicated that the absorption area is critical for improving the bioavailability of ITZ. Consequently, the bioavailability of ITZ could be improved by inhibiting precipitation in the absorption area.

Drug Amorphous Solid Dispersions Based on Poly(vinyl Alcohol): Evaluating the Effect of Poly(propylene Succinate) as Plasticizer

Although significant actions have been taken towards the utilization of poly(vinyl alcohol) (PVA) in the preparation of drug amorphous solid dispersions (ASDs) using fusion-based techniques (such as melt-quench cooling and hot-melt extrusion), several drawbacks regarding its rather high melting temperature and its thermal degradation profile make the use of the polymer extremely challenging. This is especially important when the active pharmaceutical ingredient (API) has a lower melting temperature (than PVA) or when it is thermally labile. In this vein, a previous study showed that newly synthesized polyester-based plasticizers may improve the processability and the thermal properties of PVA. However, the effects of such polyester-based plasticizers on the drug’s physicochemical and pharmaco-technical properties are yet unknown. Hence, the aim of the present study is to extend our previous findings and evaluate the use of poly(propylene succinate) (PPSu, i.e., the most promising plasticizer in regard to PVA) in the preparation of drug-loaded PVA-based ASDs. Dronedarone (DRN), a poorly water-soluble API, was selected as a model drug, and drug ASDs (using either neat PVA or PVA-PPSu) were prepared using the melt-mixing/quench cooling approach at low melting temperatures (i.e., 170 °C). DSC and pXRD analysis showed that a portion of the API remained crystalline in the ASDs prepared only with the use of neat PVA, while the samples having PPSu as a plasticizer were completely amorphous. Further evaluation with ATR-FTIR spectroscopy revealed the formation of significant intermolecular interactions between the API and the PVA-PPSu matrix, which could explain the system’s physical stability during storage. Finally, dissolution studies, conducted under nonsink conditions, revealed that the use of PVA-PPSu is able to maintain DRN’s sustained supersaturation for up to 8 h.

Photopatterned microswimmers with programmable motion without external stimuli

We introduce highly programmable microscale swimmers driven by the Marangoni effect (Marangoni microswimmers) that can self-propel on the surface of water. Previous studies on Marangoni swimmers have shown the advantage of self-propulsion without external energy source or mechanical systems, by taking advantage of direct conversion from power source materials to mechanical energy. However, current developments on Marangoni microswimmers have limitations in their fabrication, thereby hindering their programmability and precise mass production. By introducing a photopatterning method, we generated Marangoni microswimmers with multiple functional parts with distinct material properties in high throughput. Furthermore, various motions such as time-dependent direction change and disassembly of swimmers without external stimuli are programmed into the Marangoni microswimmers.

Elucidating the Molecular Mechanism of Drug-Polymer Interplay in a Polymeric Supersaturated System of Rifaximin

Supersaturated drug delivery system (SDDS) enables the solubility and sustained membrane transport of poorly water-soluble drugs. SDDS provides higher drug concentration in the dispersed phase and equilibrium in the continuous phase, which corresponds to amorphous solubility of the drug. Rifaximin (RFX) is a nonabsorbable BCS class IV drug approved for the treatment of irritable bowel syndrome and effective against Helicobacter pylori. RFX shows slow crystallization and precipitation in an acidic pH of 1.2-2, leading to obliteration of its activity in the gastrointestinal tract. The objective of the present study is to inhibit the precipitation of RFX, involving screening of polymers at different concentrations, using an in-house developed microarray plate method and solubility studies which set forth hydroxypropyl methylcellulose (HPMC) E15, Soluplus, and polyvinyl alcohol to be effective precipitation inhibitors (PIs). Drug-polymer precipitates (PPTS) are examined for surface morphology by scanning electron microscopy, solid-phase transformation by hot stage microscopy, the nature of PPTS by polarized light microscopy, and drug-polymer interactions by Fourier transform infrared and nuclear magnetic resonance spectroscopy. Besides, the unfathomed molecular mechanism of drug-polymer interplay is discerned at the air-water interface using sum-frequency generation spectroscopy to correlate the interfacial hydrogen bonding properties in bulk water. Surprisingly, all studies disseminate HPMC E15 and Soluplus as effective PIs of RFX.

Low Molecular Weight Oligomers of Poly(alkylene succinate) Polyesters as Plasticizers in Poly(vinyl alcohol) Based Pharmaceutical Applications

The plasticizing effect of three low molecular weight oligomers of aliphatic poly(alkylene succinate) polyesters, namely poly(butylene succinate) (PBSu), poly(ethylene succinate) (PESu), and poly(propylene succinate) (PPSu), on partially hydrolyzed poly(vinyl alcohol) (PVA) used in melt-based pharmaceutical applications, was evaluated for the first time. Initially, the three aliphatic polyesters were prepared by the melt polycondensation process and characterized by differential scanning calorimetry (DSC), ¹H NMR, intrinsic viscosity, and size exclusion chromatography (SEC). Subsequently, their effect on the thermophysical and physicochemical properties of PVA was thoroughly evaluated. According to the obtained results, PVA was completely miscible with all three polyesters, while PESu induced PVA’s thermal degradation, with the phenomenon starting from ~220 °C, in contrast to PBSu and PPSu, where a thermal profile similar to PVA was observed. Furthermore, molecular interactions between PVA and the prepared poly(alkylene succinate) polyesters were revealed by DSC, ATR-FTIR, and molecular dynamics simulations. Finally, melt flow index (MFI) measurements showed that, in contrast to PBSu, the use of PESu or PPSu significantly improved PVA’s melt flow properties. Hence, according to findings of the present work, only the use of low molecular weight PPSu is suitable in order to reduce processing temperature of PVA and improve its melt flow properties (plasticizing ability) without affecting its thermal decomposition.

Thermally Conductive Excipient Expands KinetiSol® Processing Capabilities

We report for the first time that incorporation of a thermally conductive excipient (TCE) modifies the thermal conductivity of the ternary drug-polymer-TCE compositions such that high-energy mixing can occur for prolonged periods at a selected steady-state temperature during the KinetiSol process. In this study, candurin, a TCE, is incorporated within a composition that is processed by high-energy mixing from the KinetiSol process to increase the thermal conductivity of the ternary composition. The improved thermal conductivity promotes heat transfer and enables the high-energy mixing applied during the KinetiSol process to be continued for prolonged time intervals at a selected steady-state temperature, instead of undergoing a continued increase in temperature when the TCE is not present in the composition. The addition of candurin does not impact the molecular structure and mixing of the drug and polymer in ASDs from solid-state NMR characterizations. Compositions with candurin achieved a steady-state processing temperature with + 5°C of the target temperature, and these compositions demonstrated the ability to mix for prolonged time periods while maintaining within this steady-state temperature range, thus enabling the formation of an ASD at a temperature that the drug does not chemically degrade. This study demonstrated that inclusion of the TCE modified the composition's thermal conductivity to efficiently dissipate heat to achieve a selected steady-state temperature during the KinetiSol process, thus providing prolonged mixing times at a lower temperature for dissolving the drug into the polymer to achieve an ASD without sacrificing product performance.

Innovations in Thermal Processing: Hot-Melt Extrusion and KinetiSol® Dispersing

Thermal processing has gained much interest in the pharmaceutical industry, particularly for the enhancement of solubility, bioavailability, and dissolution of active pharmaceutical ingredients (APIs) with poor aqueous solubility. Formulation scientists have developed various techniques which may include physical and chemical modifications to achieve solubility enhancement. One of the most commonly used methods for solubility enhancement is through the use of amorphous solid dispersions (ASDs). Examples of commercialized ASDs include Kaletra®, Kalydeco®, and Onmel®. Various technologies produce ASDs; some of the approaches, such as spray-drying, solvent evaporation, and lyophilization, involve the use of solvents, whereas thermal approaches often do not require solvents. Processes that do not require solvents are usually preferred, as some solvents may induce toxicity due to residual solvents and are often considered to be damaging to the environment. The purpose of this review is to provide an update on recent innovations reported for using hot-melt extrusion and KinetiSol® Dispersing technologies to formulate poorly water-soluble APIs in amorphous solid dispersions. We will address development challenges for poorly water-soluble APIs and how these two processes meet these challenges.

Addressing the challenges to increase the efficiency of translating nanomedicine formulations to patients

INTRODUCTION

Nanotechnology is in a growth phase for drug delivery and medical imaging. Nanomaterials with unique properties present opportunities for encapsulation of therapeutics and imaging agents, along with conjugation to ligands for targeting. Favorable chemistry of nanomaterials can create formulations that address critical challenges for therapeutics, such as insolubility and a low capacity to cross the blood-brain-barrier (BBB) and intestinal wall.

AREAS COVERED

The authors investigate challenges faced during translation of nanomedicines while suggesting reasons as to why some nanoformulations have under-performed in clinical trials. They assess physiological barriers such as the BBB and gut mucus that nanomedicines must overcome to deliver cargos. They also provide an overview with examples of how nanomedicines can be designed to improve localization and site-specific delivery (e.g., encapsulation, bioconjugation, and triggered-release).

EXPERT OPINION

There are examples where nanomedicines have demonstrated improved efficacy of payload in humans; however, most of the advantages conferred were in improved pharmacokinetics and reduced toxicity. Problematic data show susceptibility of nanoformulations against natural protective mechanisms present in the body, including distribution impediment by physiological barriers and activation of the reticuloendothelial system. Further initiatives should address current challenges while expanding the scope of nanomedicine into advanced biomedical imaging and antibiotic delivery.

Transdermal Delivery of Kidney-Targeting Nanoparticles Using Dissolvable Microneedles

INTRODUCTION

Chronic kidney disease (CKD) affects approximately 13% of the world's population and will lead to dialysis or kidney transplantation. Unfortunately, clinically available drugs for CKD show limited efficacy and toxic extrarenal side effects. Hence, there is a need to develop targeted delivery systems with enhanced kidney specificity that can also be combined with a patient-compliant administration route for such patients that need extended treatment. Towards this goal, kidney-targeted nanoparticles administered through transdermal microneedles (KNP/MN) is explored in this study.

METHODS

A KNP/MN patch was developed by incorporating folate-conjugated micelle nanoparticles into polyvinyl alcohol MN patches. Rhodamine B (RhB) was encapsulated into KNP as a model drug and evaluated for biocompatibility and binding with human renal epithelial cells. For MN, skin penetration efficiency was assessed using a Parafilm model, and penetration was imaged via scanning electron microscopy. In vivo, KNP/MN patches were applied on the backs of C57BL/6 wild type mice and biodistribution, organ morphology, and kidney function assessed.

RESULTS

KNP showed high biocompatibility and folate-dependent binding in vitro, validating KNP's targeting to folate receptors in vitro. Upon transdermal administration in vivo, KNP/MN patches dissolved within 30 min. At varying time points up to 48 h post-KNP/MN administration, higher accumulation of KNP was found in kidneys compared with MN that consisted of the non-targeting, control-NP. Histological evaluation demonstrated no signs of tissue damage, and kidney function markers, serum blood urea nitrogen and urine creatinine, were found to be within normal ranges, indicating preservation of kidney health.

CONCLUSIONS

Our studies show potential of KNP/MN patches as a non-invasive, self-administrable platform to direct therapies to the kidneys.

Topical green tea formulation with anti-hemorrhagic and antibacterial effects

Objective(s):

Potentially preventable death from uncontrolled hemorrhage clearly indicates the importance of simple, fast and efficient ways to achieving hemostasis. The aim of this study was to develop a topical formulation of green tea extract for reducing bleeding that can be helpful in hemorrhage control.

Materials and Methods:

Hydroalcoholic extract of green tea was isolated from Camellia sinensis and formulated in polyvinyl alcohol (PVA) to achieve two concentrations of 2% and 4% v/v. Folin-Ciocalteau assay was used to determine the total amount of tannins in extract. Rheological behavior of solutions was investigated by measuring viscosity at shear rates of 0–200 sec⁻¹. Quantitative and qualitative microbial limit tests and minimum inhibitory concentration (MIC) assay were done. The effect of formulations on bleeding time was evaluated in an animal model.

Results:

The total amount of tannin in green tea extract was 3.8% w/w and addition of green tea significantly increased the viscosity of PVA. The results of MIC assay showed that PVA could not inhibit the growth of bacteria, while, 716 µg/ml of green tea and 2860 µg/ml of green tea/PVA 4% inhibited the growth of Staphylococcus aureus and Pseudomonas aeruginosa. In an animal study both 2% and 4% formulations were able to stop hemorrhage approximately at an equal time compared with tranexamic acid (TXA) 50 mg/ml as a control and the lowest bleeding time was 6.4±0.51 sec for green tea/PVA 4%.

Conclusion:

Based on our results, the topical formulation of green tea extract in PVA has a great potential for anti-hemorrhage applications.

Impact of HPMCAS on the Dissolution Performance of Polyvinyl Alcohol Celecoxib Amorphous Solid Dispersions

Amorphous solid dispersions (ASDs) have been proven to increase the bioavailability of poorly soluble drugs. It is desirable that the ASD provide a rapid dissolution rate and a sufficient stabilization of the generated supersaturation. In many cases, one polymer alone is not able to provide both features, which raises a need for reasonable polymer combinations. In this study we aimed to generate a rapidly dissolving ASD using the hydrophilic polymer polyvinyl alcohol (PVA) combined with a suitable precipitation inhibitor. Initially, PVA and hydroxypropylmethylcellulose acetate succinate (HPMCAS) were screened for their precipitation inhibitory potential for celecoxib in solution. The generated supersaturation in presence of PVA or HPMCAS was further characterized using dynamic light scattering. Binary ASDs of either PVA or HPMCAS (at 10% and 20% drug load) were prepared by hot-melt extrusion and solid-state analytics were conducted using differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD) and fourier-transformed infrared spectroscopy (FT-IR). The non-sink dissolution studies of the binary ASDs revealed a high dissolution rate for the PVA ASDs with subsequent precipitation and for the HPMCAS ASDs a suppressed dissolution. In order to utilize the unexploited potential of the binary ASDs, the PVA ASDs were combined with HPMCAS either predissolved or added as powder and also formulated as ternary ASD. We successfully generated a solid formulation consisting of the powdered PVA ASD and HPMCAS powder, which was superior in monophasic non-sink dissolution and biorelevant biphasic dissolution studies compared to the binary and ternary ASDs.

Development of 3D Printed Tablets by Fused Deposition Modeling Using Polyvinyl Alcohol as Polymeric Matrix for Rapid Drug Release

In this study, the processability of polyvinyl alcohol (PVA), a water-soluble polymer, into melt-extruded filaments and then into 3D printed tablets by fused deposition modeling was studied. PVA is semicrystalline with Tg and m.p. of ~45°C and ~190°C, respectively. After screening several plasticizers, sorbitol was selected to enhance melt extrudability of PVA. Carvedilol and haloperidol, 2 basic compounds with pH-dependent solubility, were used as model drugs. Miscibility of the drugs with PVA, with and without added sorbitol as plasticizer, was also tested to determine whether any amorphous solid dispersion was formed that would facilitate rapid and pH-independent dissolution. Finally, the drug release from physical mixtures, crushed extrudates, and printed tablets were determined. Owing to high m.p. and high melt viscosity of PVA, filaments containing 10% and 20% drug required 180°C-190°C for extrusion, which could be reduced to ~150°C by adding 10% sorbitol. The printing temperature of 210°C was, however, required. Miscibility of carvedilol and haloperidol with PVA were, respectively, ~20% and <10%. PVA provided complete drug release from 3D printed tablets with 10% and 20% carvedilol and 60% infill in ~45 min at both pH 2 and 6.8. However, despite relatively rapid dissolution rate, high processing temperature and limited drug-polymer miscibility could be potential development issues with PVA.

Opportunities for Successful Stabilization of Poor Glass-Forming Drugs: A Stability-Based Comparison of Mesoporous Silica Versus Hot Melt Extrusion Technologies

Amorphous formulation technologies to improve oral absorption of poorly soluble active pharmaceutical ingredients (APIs) have become increasingly prevalent. Currently, polymer-based amorphous formulations manufactured by spray drying, hot melt extrusion (HME), or co-precipitation are most common. However, these technologies have challenges in terms of the successful stabilization of poor glass former compounds in the amorphous form. An alternative approach is mesoporous silica, which stabilizes APIs in non-crystalline form via molecular adsorption inside nano-scale pores. In line with these considerations, two poor glass formers, haloperidol and carbamazepine, were formulated as polymer-based solid dispersion via HME and with mesoporous silica, and their stability was compared under accelerated conditions. Changes were monitored over three months with respect to solid-state form and dissolution. The results were supported by solid-state nuclear magnetic resonance spectroscopy (SS-NMR) and scanning electron microscopy (SEM). It was demonstrated that mesoporous silica was more successful than HME in the stabilization of the selected poor glass formers. While both drugs remained non-crystalline during the study using mesoporous silica, polymer-based HME formulations showed recrystallization after one week. Thus, mesoporous silica represents an attractive technology to extend the formulation toolbox to poorly soluble poor glass formers.

A comprehensive understanding of lowly-hydrolyzed polyvinyl alcohol-based ternary solid dispersions with the use of a combined mixture-process design

We recently reported lowly hydrolyzed polyvinyl alcohol (L-PVA, 70-74% hydrolyzed, about 580 polymerized, JR-05) as a promising matrix for hot-melt extrusion (HME) due to its unique micelle formation ability compared to the most commonly used PVA (87-89% hydrolyzed, about 580 polymerized). In the present study, we focused on the effect of composition [indomethacin (IND), L-PVA, sorbitol] and process parameters (temperature and screw speed) on each response, i.e. processing torque, and physicochemical properties such as residual crystallinity, residual ratio, and area under the dissolution curve (AUDC) in supersaturated solution using a HME by applying the design of experiment (DoE) approach. To overcome the poor processability of L-PVA, given its semicrystalline nature, we applied sorbitol as a plasticizer and systematically and simultaneously evaluated its influence on the outputs based on the mixture design combined with process factors. Few studies have focused on comprehensive evaluation of the composition and HME process conditions because obtaining a design space requires numerous experiments. We found that incorporating sorbitol into the L-PVA greatly improved the processing torque. However, sorbitol negatively influenced the degree of residual crystallinity and the AUDC of IND. Lastly, we established a laboratory-scale design space that could achieve high supersaturation and ensure adequate miscibility between each component, using an acceptable processing torque for HME, by applying the minimum amount of sorbitol. These fundamental results suggest that sorbitol maximizes the potency of L-PVA as a carrier in HME.

Solidification to improve the biopharmaceutical performance of SEDDS: Opportunities and challenges

Self-emulsifying drug delivery systems (SEDDS) offer potential for overcoming the inherent slow dissolution and poor oral absorption of hydrophobic drugs by retaining them in a solubilised state during gastrointestinal transit. However, the promising biopharmaceutical benefits of liquid lipid formulations has not translated into widespread commercial success, due to their susceptibility to long term storage and in vivo precipitation issues. One strategy that has emerged to overcome such limitations, is to combine the solubilisation and dissolution enhancing properties of lipids with the stabilising effects of solid carrier materials. The development of intelligent hybrid drug formulations has presented new opportunities to harness the potential of emulsified lipids in optimising oral bioavailability for lipophilic therapeutics. Specific emphasis of this review is placed on the impact of solidification approaches and excipients on the biopharmaceutical performance of self-emulsifying lipids, with findings highlighting the key design considerations that should be implemented when developing hybrid lipid-based formulations.

Homogeneity of amorphous solid dispersions - an example with KinetiSol®

KinetiSol^® is a high-shear, fusion-based technology capable of producing stable amorphous solid dispersions (ASDs) without the assistance of solvent. KinetiSol^® has proven successful with multiple challenging BCS class II and IV drugs, where drug properties like thermal instability or lack of appreciable solubility in volatile solvents make hot melt extrusion or spray drying unfeasible. However, there is a necessity to characterize the ASDs like those made by the KinetiSol^® process, in order to better understand whether KinetiSol^® is capable of homogeneously dispersing drug throughout a carrier in a short (<40 s) processing time. Our study utilized the high melting point, BCS class II drug, meloxicam, in order to evaluate the degree of homogeneity of 1, 5, and 10% w/w KinetiSol^®-processed samples. Powder blend homogeneity and content uniformity were evaluated, and all samples demonstrated a meloxicam concentration % relative standard deviation of ≤2.0%. SEM/EDS was utilized to map elemental distribution of the processed samples, which confirmed KinetiSol^®-processed materials were homogeneous at a 25 µm² area. Utilizing Raman spectroscopy, we were able to verify the amorphous content of the processed samples. Finally, we utilized ssNMR ¹H spin-lattice relaxation measurement to evaluate the molecular miscibility of meloxicam with the polymer at 1% w/w drug load, for the first time, and determined the processed sample was highly miscible at ∼200 nm scale. In conclusion, we determined the KinetiSol^® process is capable of producing ASDs that are homogeneously and molecularly well-dispersed drug-in-polymer at drug concentrations as low as 1% w/w.

Theoretical and practical evaluation of lowly hydrolyzed polyvinyl alcohol as a potential carrier for hot-melt extrusion

Polyvinyl alcohol (PVA) is considered to be an unsuitable carrier for hot-melt extrusion (HME) due to its low processability. In this study, we focused on a lowly hydrolyzed PVA (JR-05, 70.0-74.0% hydrolyzed, L-PVA) to evaluate the potential use of L-PVA as a carrier for HME using the Hoftyzer and Krevelen method and thermodynamic models. These evaluations for drug-polymer systems based on the Flory-Huggins theory predicted the physicochemical properties of the solubility and miscibility between indomethacin (IND) and PVAs. Prior to initiating formulation studies, construction of IND and PVA phase diagrams provided guidance for design process conditions in HME. On the basis of the results of the validation studies, a conventional grade of PVA (JP-05, 87.0-89.0% hydrolyzed) is unlikely to be suitable as a carrier of HME due to its low plasticity, resulting in rapid recrystallization in the evaluation of in vitro dissolution and stability caused by poor miscibility. On the other hand, JR-05 demonstrated high processability, leading to the preparation of miscible extrudate with a high stability and an excellent in vitro dissolution profile due to its unique micelle-forming capability. These findings suggest that L-PVA brings about new carrier options among non-ionic polymers for HME.

An Insight into Stabilization Mechanism of a Solid Dispersion of Indomethacin/Partially Hydrolyzed Polyvinyl Alcohol Prepared by Hot-Melt Extrusion

We examined the effect of hot-melt extrusion condition on the physical stability of the solid dispersion prepared using partially hydrolyzed polyvinyl alcohol (PVOH). The hot-melt extrusion of indomethacin (IMC) and PVOH mixed at the weight ratio of 3 : 7, 5 : 5 and 7 : 3 was performed either at 170 or 190°C to prepare the IMC/PVOH hot-melt extrudate (HME). Differential scanning calorimetry represented that IMC was mixed with PVOH on a scale of several tens of nanometer in all the HMEs with different weight ratio. ¹³C solid-state NMR measurement revealed that an intermolecular interaction was formed between a carboxylic group of IMC and a hydroxy group of PVOH in the HMEs. The intermolecular interaction in the HMEs was stronger at the higher extrusion temperature. At the low IMC loading, the IMC molecules could be mixed with the amorphous PVOH at the molecular level, and the remained PVOH without interaction formed the crystal phase. On the other hand, at the high IMC loading, most PVOH could be amorphized by the interaction with IMC, and the excess IMC which did not interact with PVOH formed the IMC-rich domain. The IMC/PVOH HME at the weight ratio of 7 : 3 extruded at higher extrusion temperature showed higher physical stability of amorphous IMC compared with that extruded at lower extrusion temperature. The hot-melt extrusion process at higher temperature provided the rapid melting of PVOH crystal phase, resulted in the homogeneous mixing with IMC and the formation of stronger intermolecular interaction.

Expanding the Application and Formulation Space of Amorphous Solid Dispersions with KinetiSol®: a Review

Due to the high number of poorly soluble drugs in the development pipeline, novel processes for delivery of these challenging molecules are increasingly in demand. One such emerging method is KinetiSol, which utilizes high shear to produce amorphous solid dispersions. The process has been shown to be amenable to difficult to process active pharmaceutical ingredients with high melting points, poor organic solubility, or sensitivity to heat degradation. Additionally, the process enables classes of polymers not conventionally processable due to their high molecular weight and/or poor organic solubility. Beyond these advantages, the KinetiSol process shows promise with other applications, such as the production of amorphous mucoadhesive dispersions for delivery of compounds that would also benefit from permeability enhancement.

Recent Trends in the Fabrication of Starch Nanofibers: Electrospinning and Non-electrospinning Routes and Their Applications in Biotechnology

Electrospinning a versatile and the most preferred technique for the fabrication of nanofibers has revolutionized by opening unlimited avenues in biomedical fields. Presently, the simultaneous functionalization and/or post-modification of as-spun nanofibers with biomolecules has been explored, to serve the distinct goals in the aforementioned field. Starch is one of the most abundant biopolymers on the earth. Besides, being biocompatible and biodegradable in nature, it has unprecedented properties of gelatinization and retrogradation. Therefore, starch has been used in numerous ways for wide range of applications. Keeping these properties in consideration, the present article summarizes the recent expansion in the fabrication of the pristine/modified starch-based composite scaffolds by electrospinning along with their possible applications. Apart from electrospinning technique, this review will also provide the comprehensive information on various other techniques employed in the fabrication of the starch-based nanofibers. Furthermore, we conclude with the challenges to be overcome in the fabrication of nanofibers by the electrospinning technique and future prospects of starch-based fabricated scaffolds for exploration of its applications.

3D printing of a wearable personalized oral delivery device: A first-in-human study

Despite the burgeoning interest in three-dimensional (3D) printing for the manufacture of customizable oral dosage formulations, a U.S. Food and Drug Administration-approved tablet notwithstanding, the full potential of 3D printing in pharmaceutical sciences has not been realized. In particular, 3D-printed drug-eluting devices offer the possibility for personalization in terms of shape, size, and architecture, but their clinical applications have remained relatively unexplored. We used 3D printing to manufacture a tailored oral drug delivery device with customizable design and tunable release rates in the form of a mouthguard and, subsequently, evaluated the performance of this system in the native setting in a first-in-human study. Our proof-of-concept work demonstrates the immense potential of 3D printing as a platform for the development and translation of next-generation drug delivery devices for personalized therapy.

Investigating the performance of drug delivery system of fluconazole made of nano-micro fibers coated on cotton/polyester fabric

Polymer-based drug delivery systems are suitable to optimize the therapeutic properties of drugs and to render them safer, more effective and reliable. Long-term or repeated use of oral administration of fluconazole for treating chronic candidiasis in the patient and partially abandoned treatment lead to the resistant strains of the fungus Candida albicans and severity of the disease. In this study, the use of nanofibers and microfibers containing fluconazole for local drug delivery to increase the efficiencies and reduce the side effects caused by taking the drug was studied. Morphology, microstructure and chemical composition of PVA nanofibers containing fluconazole were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). As well as, the DSC test was indicated presence of fluconazole in PVA fibrous mats. The rate of drug release was investigated by UV-Vis spectrophotometery and swelling technique. SEM images showed that the nanofibers with uniform structure without beads were produced. The mechanical properties of the pristine PVA nanofiber and fibrous mat containing drug were evaluated. The release of fluconazole from PVA nanofibers in pH of 7.4 and at 37 °C was investigated. The results presented that the drug release rate is dependent on the morphology and structure of PVA nanofibers and could be adjusted in desired dosage. The presented products are applicable in the high production form for medical textile industry.