In this study, we fabricated pH-sensitive polyvinylpyrrolidone/acrylic acid (PVP/AA) hydrogels by a free-radical polymerisation method with variation in the content of monomer, polymer and cross-linking agent. Swelling was performed in USP phosphate buffer solutions of pH 1.2, 5.5, 6.5 and 7.5 with constant ionic strength. Network structure was evaluated by different parameters and FTIR confirmed the formation of cross-linked hydrogels. X-ray crystallography showed molecular dispersion of tramadol HCl. A drug release study was carried out in phosphate buffer solutions of pH 1.2, 5.5 and 7.5 for selected samples. It was observed that swelling and drug release from hydrogels can be modified by changing composition and degree of cross-linking of the hydrogels under investigation. Swelling coefficient was high at higher pH values except for the one containing high PVP content. Drug release increased by increasing the pH of the medium and AA contents in hydrogels while increasing the concentration of cross-linking agent had the opposite effect. Analysis of the drug release mechanism revealed non-Fickian transport of tramadol from the hydrogels.

The aim of this work was to develop, optimize and characterize a silymarin-laden polyvinylpyrrolidone (PVP)-polyethylene glycol (PEG) polymeric composite to resolve low aqueous solubility and dissolution rate problem of the drug. A number of silymarin-laden polymeric formulations were fabricated with different quantities of PVP K-30 and PEG 6000 by the solvent-evaporation method. The effect of PVP K-30 and PEG 6000 on the aqueous solubility and dissolution rate was investigated. The optimized formulation and its constituents were characterized using powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) techniques. Both the PEG 6000 and PVP K-30 positively affected the aqueous solubility and dissolution rate of the drug. In particular, a formulation consisting of silymarin, PVP K-30 and PEG 6000 (0.25/1.5/1.5, w/w/w) furnished the highest solubility (24.39±2.95 mg/mL) and an excellent dissolution profile (~100% in 40 min). The solubility enhancement with this formulation was ~1150-fold as compared to plain silymarin powder. Moreover, all the constituents existed in the amorphous state in this silymarin-laden PVP-PEG polymeric composite. Accordingly, this formulation might be a promising tool to administer silymarin with an enhanced effect via the oral route.

Rheumatoid arthritis (RA) is an autoimmune disease associated with severe joint pain. Herein, we report lornoxicam loaded cellulosic microsponge gel formulation with sustained anti-inflammatory effects that are required to manage arthritic pain. The microsponges were formulated using quasi emulsion-solvent diffusion method employing four different surfactant systems, namely polyvinyl alcohol (PVA), Tween80, Gelucire 48/16 and Gelucire 50/13. All the lornoxicam loaded microsponge formulations were extensively characterized with a variety of analytical tools. The optimized microsponge formulation was then converted into gel formulation. The lornoxicam loaded microsponge gel formulation had adequate viscosity and sufficient pharmaceutical properties as confirmed by the texture analysis and the drug release followed Super case II transport. It is noteworthy that we described the preparation of a new cellulosic polymers based microsponge system for delivery of lornoxicam to provide quick as well as lasting (sustained) anti-inflammatory effects in rats using carrageenan induced rat paw edema model. We were able to demonstrate a 72% reduction in inflammation within 4 h using the optimize transdermal gel formulation utilizing Transcutol P as permeation enhancer and with the aid of skin micro-piercing by microneedles, hence, demonstrating the potential of this microsponge gel formulation in arthritis management.

In the present study pH-sensitive polyvinylpyrrolidone/acrylic acid (PVP/AA) hydrogels were synthesized by free radical polymerization in the presence of ethylene glycol dimethacrylate (EGDMA) as a...