Abstract

The objective of the present study is to develop colon targeted drug delivery systems for albendazole using guar gum as a carrier. Matrix tablets containing various proportions of guar gum were prepared by wet granulation technique using starch paste as a binder. The tablets were evaluated for hardness and drug content, and were subjected to in vitro drug release studies. The amount of albendazole released from the matrix tablets at different time intervals was estimated by HPLC method. Guar gum matrix tablets released 4 to 17% of albendazole in the physiological environment of stomach and small intestine depending on the proportion of guar gum used in the formulation. When the dissolution study was continued in simulated colonic fluids (rat caecal content medium) the matrix tablets containing 10% of guar gum released another 83% of albendazole after degradation into 2-3 pieces at the end of 24 h of the study. The matrix tablets containing 20% of guar gum also released about 44% of albendazole in simulated colonic fluids at the end of 24 h of the study indicating the susceptibility of the guar gum formulations to the rat caecal contents. The results of the study show that matrix tablets containing either 10% or 20% of guar gum are most likely to provide targeting of albendazole for local action in the colon. The guar gum matrix tablets of albendazole showed no change either in physicalappearance, drug content or in dissolution pattern after storage at 40°/75 % RH for 6 mo. Differentialscanning calorimetry indicated no possibility of interaction between albendazole and guargum.