Synthesis of dual responsive carbohydrate polymer based IPN microbeads for controlled release of anti-HIV drug.

The present study aims at preparation of dual responsive interpenetrating polymer network hydrogel microbeads from sodium alginate and functionally modified guar gum. Guar gum was modified by graft copolymerization using N-vinylcaprolactam, the maximum % grafting 123.2, obtained at different optimized conditions. The graft copolymer was blended with sodium alginate to form hydrogel microbeads by emulsion crosslinking method using glutaraldehyde as crosslinker. Zidovudine, an anti-HIV drug was encapsulated with 68% encapsulation efficiency. Fourier transform infrared spectroscopy, 1 H nuclear magnetic resonance spectroscopy, scanning electron microscopy, differential scanning calorimetry and X-ray diffraction studies justified the grafting reaction, structure, morphology and polymer-drug interactions, respectively. Swelling studies ascertained that microbeads were potentially sensitive to both pH and temperature. In vitro release studies were investigated in pH 1.2 and 7.4, the release time enhanced up to 34h in pH 7.4 at 37°C.