FORMULATION AND EVALUATIONOF AMOXYCILLIN: THREE-LAYER GUAR GUM MATRIX TABLET

The objective of the study is to design gastro retentive drug delivery systems for Amoxycillin trihydrate. It was prepared with the objective to obtain site-specific drug delivery for the stomach and to extend its duration of action. The sustained release of amoxicillin is desired because of its short biological half-life. The preparation was carried out by using guar gum as a carrier in the form of a three-layer matrix tablet. Amoxycillin trihydrate was chosen as a model drug because of its site-specificity. Matrix tablets containing either 30 % (M) of guar gum were prepared by wet granulation technique using starch paste as a binder. Three-layer matrix tablets of Amoxycillin were prepared by compressing on both sides of guar gum matrix tablet granules of Amoxycillin M with either 50 (TLM) of guar gum granules as release retardant layers. Both the matrix and three-layer matrix tablets were evaluated for weight variation, hardness, friability, buoyancy and in-vitro dissolution studies. Optimized formulation of amoxicillin was found to have increased gastric residence prolonging the release of drug with 74% (matrix tablet) and 81% (three layer matrix tablet) of drug release in 8 hours by diffusion. The mechanism of drug release was found to be diffusion and followed combination of zero order and first order kinetics. Hence gastro retentive drug delivery system of Amoxycillin trihydrate is a promising approach as it can lead to decrease in the frequency of administration and ultimately lead to better patient compliance.