FORMULATION AND IN VITRO EVALUATION OF GASTRORETENTIVE FAMOTIDINE HOLLOW MICROSPHERES

The main aim of this study is to develop a gastro retentive multiple unit floating drug delivery system for a drug which is poorly absorbed from lower gastrointestinal tract of famotidine. The hollow micro spheres were prepared by the emulsion solvent diffusion technique using eudragit RS 100 as a release rate controlling polymer in the ratios 1:1, 1:2 ,1:3,and 1:4.The prepared microspheres were evaluated for drug-polymer compatibility, micromeritic properties, drug entrapment efficiency, in-vitro buoyancy and drug release studies. The mean particle size increased with increase in the polymer concentration. The micromeritic properties were found to be improved when compared to pure drug .Scanning electron microscopy confirmed the hollow structure with smooth external surface. The drug and polymer were found to be compatible as seen in IR studies. The entrapment efficiency of formulation E1-E4 were 70.42%, 70.12%, 69.22% and 67.78% and for the formulation C1-C4 were 72.19%, 68.67%, 67.14% and 66.87%, cellulose acetate containing microspheres showed a desirable high drug content and entrapment efficiency respectively. The microspheres floated up to 10 h over the surface of the gastric buffer medium and the buoyancy percentage was found to be in the range of 60-39% of E1-E4and C1-C4. In-vitro drug release studies showed that the prepared microspheres exhibited prolonged drug release for more than 12 hours. The mechanism of drug release wasfound to be a combination of both peppas and zero order release kinetics. The developed floating microspheres of aceclofenac may be used for prolonged drug release for at least 12 h for maximizing the therapeutic efficacy along with patient compliance. Keywords: Famotidine, Ethyl acetate, acetone, Eudragit RL100, Higuchi's model, PVA, scanning electron microscopy