Polypropylene Graft Poly(methyl methacrylate) Graft Poly(N-vinylimidazole) as a Smart Material for pH-Controlled Drug Delivery

Surface modification of polypropylene (PP) films was achieved using gamma-irradiation-induced grafting to provide an adequate surface capable of carrying glycopeptide antibiotics. The copolymer was obtained following a versatile two-step route; pristine PP was exposed to gamma rays and grafted with methyl methacrylate (MMA), and afterward, the film was grafted with N-vinylimidazole (NVI) by simultaneous irradiation. Characterization included Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and physicochemical analysis of swelling and contact angle. The new material (PP-g-MMA)-g-NVI was loaded with vancomycin to quantify the release by UV-vis spectrophotometry at different pH. The surface of (PP-g-MMA)-g-NVI exhibited pH-responsiveness and moderate hydrophilicity, which are suitable properties for controlled drug release.

In vivo Evaluation of Theophylline Sustained Release Matrix Tablets Containing Low Viscosity Guar Gum

The present investigation was carried out to evaluate the utility of guar gum as a hydrophilic matrix carrier in the design of oral controlled drug delivery. Based on the earlier reports, the low viscosity guar gum appears to be superior to medium and high viscosity grades of guar gum in providing a sustained delivery of theophylline along the GI tract. Conducting in vivo studies on theophylline matrix tablets containing 10% of low viscosity guar gum as a representative formulation assessed the in vivo performance of the guar gum matrix tablets. The in vivo studies were carried out in dogs. The effective concentration of theophylline was sustained for a period of 16 hours. The extended tmax, reduced absorption rate constant, prolonged MRT, unchanged Cmax and unchanged bioavailability indicate a controlled release of theophylline from the guar gum matrix tablets resulting in a sustained absorption and prolonged blood levels of theophylline. The theophylline matrix tablets showed blood levels well below 15 ?g/mL indicating freedom from adverse effects. Based on the studies, guar gum appears to be a potential carrier in the design of oral controlled drug delivery systems.