PROCESS OPTIMIZATION, FORMULATION AND EVALUATION OF HYDROGEL {GUARGUM-G-POLY (ACRYLAMIDE)} BASED DOXOFYLLINE MICROBEADS

Abstract

Objective: The objective of the present study was to improve the physical and chemical properties of natural polymers and to reduce the cost of product by graft copolymerization techniques using a natural polymer (Guar gum) and a synthetic polymer {poly (acrylamide)}. The optimized formulation of hydrogel was formulated as microbeads and loaded with Doxofylline and characterized with different parameters.

Methods: Graft copolymer of guar gum-g-poly (acrylamide) was prepared by free radical polymerization technique in a specially designed jacked reaction vessel under constant flow of nitrogen. To initiate the reaction, Ceric ammonium nitrate (CAN) was used as reaction initiator. The graft co-polymer was characterised by using FTIR, TGA, and SEM. Polymeric blend beads of the grafted copolymer with sodium alginate were prepared by cross linking with calcium chloride in ionic gelation method and used to deliver a model new generation anti asthmatic drug, Doxofylline. Preparation condition of beads was optimized by considering the percentage entrapment efficiency, particle size, swelling capacity of beads in different P^H conditions and their release data.

Results: The formation of grafted copolymers is confirmed by FTIR studies and TGA studies showed a comparatively higher thermal stability of grafted copolymer. The pAAm-g-GG/sodium alginate microbeads were almost spherical in shape as indicated by the SEM studies. Swelling index was found to be maximum in Phosphate buffer P^H 7.4 and minimum in Phosphate buffer P^H 9.2. Release of doxofylline was found to be in a controlled manner with increasing polyacrylamide content in the copolymer and sodium alginate content in microbeads and higher release was observed in P^H 7.4 medium than that of P^H 1.2. In vitro release kinetics of doxofylline from the polymeric beads followed Higuchi kinetics model.

Conclusion: Hydrogel based Doxofylline microbeads were successfully developed by using optimized batches of Guar gum-g-poly (acrylamide) and sodium alginate by free radical ionization technique. All the characterization parameters came under acceptance criteria.  

Key words: Hydrogel, Microbeads, Guar gum, Acrylamide, Sodium alginate