Hybrid Dissolving Microneedle-Mediated Delivery of Ibuprofen: Solubilization, Fabrication, and Characterization

Microneedles have recently emerged as a promising platform for delivering therapeutic agents by disrupting the skin, resulting in improved and high drug delivery via this route. Ibuprofen is widely used topically and orally for chronic pain conditions; to avoid untoward gastric effects, topical application is preferred over the oral route. This study aimed to enhance the solubility of the poorly water-soluble ibuprofen using Soluplus (SP) as a solubilizer and to fabricate dissolving microneedle patches of the drug. The fabricated patches were compared with marketed oral and topical formulations of ibuprofen. A 432-fold increase was observed in the solubility of the drug at 8% SP. The FTIR studies revealed that the drug and polymers were compatible. MNs were of uniform morphology and released the drug in a predictable manner. The in vivo analysis on healthy human volunteers revealed a Cmax of 28.7 µg/mL ± 0.5 with a T_max of 24 h and a MRT of 19.5 h, which was significantly higher than that observed for commercially available topical formulations. The prepared ibuprofen microneedles have higher bioavailability and MRT at a lower dose (165 µg) as compared to tablet and cream doses (200 mg).

Fabrication of chitosan-polyvinyl alcohol and silk electrospun fiber seeded with differentiated keratinocyte for skin tissue regeneration in animal wound model

Hybrid fibrous mat containing cell interactive molecules offers the ability to deliver the cells and drugs in wound bed, which will help to achieve a high therapeutic treatment. In this study, a co-electrospun hybrid of polyvinyl alcohol (PVA), chitosan (Ch) and silk fibrous mat was developed and their wound healing potential by localizing bone marrow mesenchymal stem cells (MSCs)-derived keratinocytes on it was evaluated in vitro and in vivo. It was expected that fabricated hybrid construct could promote wound healing due to its structure, physical, biological specifications. The fabricated fibrous mats were characterized for their structural, mechanical and biochemical properties. The shape uniformity and pore size of fibers showed smooth and homogenous structures of them. Fourier transform infrared spectroscopy (FTIR) verified all typical absorption characteristics of Ch-PVA + Silk polymers as well as Ch-PVA or pure PVA substrates. The contact angle and wettability measurement of fibers showed that mats found moderate hydrophilicity by addition of Ch and silk substrates compared with PVA alone. The mechanical features of Ch-PVA + Silk fibrous mat increase significantly through co-electrospun process as well as hybridization of these synthetic and natural polymers. Higher degrees of cellular attachment and proliferation obtained on Ch-PVA + Silk fibers compared with PVA and Ch-PVA fibers. In terms of the capability of Ch-PVA + Silk fibers and MSC-derived keratinocytes, histological analysis and skin regeneration results showed this novel fibrous construct could be suggested as a skin substitute in the repair of injured skin and regenerative medicine applications.

Enhancement of biochemical aspects of lipase adsorbed on halloysite nanotubes and entrapped in a polyvinyl alcohol/alginate hydrogel: strategies to reuse the most stable lipase

Entrapment of halloysite nanotubes (HNTs) loaded with enzyme, into a polymer matrix (PVA/Alg), is a way to produce an environment surrounding the adsorbed enzyme molecules which improves the enzyme properties such as storage and operational stability. Hence, in this study, we optimised the factors affecting lipase adsorption onto halloysite nanotubes including halloysite amounts (5, 42.5 and 80 mg), lipase concentrations (30, 90 and 150 µg/ml), temperatures (5, 20 and 35 °C) and adsorption times (30, 165 and 300 min). The optimal conditions were determined as an halloysite amount of 50 to 80 mg, a lipase concentration of 30 to 57 μg/ml, an adsorption temperature of 20 °C and an adsorption time of 165 min, which resulted in a specific activity and adsorption efficiency of 15,000 (U/g protein) and 70%, respectively. Then, lipase adsorbed under optimal conditions was entrapped in a PVA/Alg hydrogel. The formation mechanism of immobilized lipase was investigated by FESEM and FTIR. Subsequent entrapment of adsorbed lipase improved the lipase storage and operational stability. K_m, V_max, K_cat and K_cat/K_m values showed an increase in the entrapped HNT-lipase performance in comparison with the free and adsorbed lipase.

Synthesis of a chitosan/polyvinyl alcohol/activate carbon biocomposite for removal of hexavalent chromium from aqueous solution

In this study, a biocomposite of chitosan/poly vinyl alcohol/activated carbon was synthesized and used for hexavalent chrome removal from aqueous solution. The synthesized adsorbent was characterized by Scanning Electron Microscopy (SEM) and Fourier Transform Infrared (FTIR) analysis. The effect of important variables such as pH, concentration, contact time, temperature, and adsorbent dosage was investigated. The value of pH_PZC for the adsorbent was evaluated at 4.9. Results showed that adsorption of chrome onto the adsorbent follows the Langmuir isotherm model and has a pseudo-second-order kinetic model. The maximum capacity of chrome adsorption was determined 109.89 (mg/g) according to the Langmuir isotherm model. According to adsorption results, the removal percentage of chrome increases with increasing the activated carbon content in the biocomposite, the adsorbent dosage, and decreasing the initial chrome concentration, pH, and temperature. The results showed that the synthesized adsorbent can be used as an effective adsorbent for chrome removal from aqueous solutions.

Heparin binding chitosan derivatives for production of pro-angiogenic hydrogels for promoting tissue healing

Our aim was to develop a biocompatible hydrogel that could be soaked in heparin and placed on wound beds to improve the vasculature of poorly vascularized wound beds. In the current study, a methodology was developed for the synthesis of a new chitosan derivative (CSD-1). Hydrogels were synthesized by blending CSD-1 for either 4 or 24h with polyvinyl alcohol (PVA). The physical/chemical interactions and the presence of specific functional groups were confirmed by Fourier transform infrared (FT-IR) spectroscopy and proton nuclear magnetic resonance (¹H NMR). The porous nature of the hydrogels was confirmed by scanning electron microscopy (SEM). Thermal gravimetric analysis (TGA) showed that these hydrogels have good thermal stability which was slightly increased as the blending time was increased. Hydrogels produced with 24h of blending supported cell attachment more and could be loaded with heparin to induce new blood vessel formation in a chick chorionic allantoic membrane assay.

Topical hydrogel matrix loaded with Simvastatin microparticles for enhanced wound healing activity

A prolonged release drug delivery system was developed by loading Simvastatin-chitosan microparticles into poly vinyl alcohol (PVA) hydrogels for enhanced wound healing efficiency. The microparticles prepared by ionic gelation method with varying composition of chitosan and surfactants (Tween 80/Pluronic F-127) were optimized for entrapment efficiency, morphology and drug-polymer interactions. Microparticles prepared with 0.3% between 80 and 0.5:5 chitosan: drug ratio showed maximum entrapment efficiency of 82% with spherical morphology and mild interaction between drug and chitosan. 5% PVA solutions loaded with pure drug and drug loaded microparticles at three different doses (2.5mg, 5mg and 10mg equivalent of drug) were chemically cross linked using gluteraldehyde and HCl. The formulated hydrogels were optimized for swelling, in vitro release behavior and in vivo wound healing effect. Hydrogels containing 2.5mg equivalent dose of Simvastatin microparticles exhibited maximum cumulative percentage drug release of 92% (n=3) at the end of 7days. The in vitro drug release data was supported by the higher swelling index of the low dose hydrogels. The in vivo wound healing study was performed using Wistar rats (n=30, 5 groups with 6 animals in each group) for the formulated hydrogels (at 3 doses) and compared with the untreated animals and the positive control group treated with conventional topical Simvastatin ointment (1%). The wound healing effect was comparable to the in vitro results, wherein the animals treated with low dose hydrogels (replaced every 7days) exhibited considerable reduction in the wound area compared to medium and high dose hydrogels. Statistically significant difference (P<0.05) was observed in the wound area of the animals treated with low dose hydrogels compared to 1% ointment and untreated animals, as estimated by two-way ANOVA. The histopathology images of the different groups of animals also displayed the comparative changes in the wound healing process. Hence, the incorporation of Simvastatin-chitosan microparticles in PVA hydrogels has demonstrated significant wound healing efficiency at optimum dose.