Formulation and Evaluation of Gastroretentive Floating Microspheres of Lafutidine

Background: Gastroretentive floating microsphere containing Lafutidine, a second generation histamine H2-receptor antagonist were prepared by ionotropic gelation technique by using sodium alginate, HPMC K4M, ethyl cellulose as polymers, sodium bicarbonate as gas generating agent and calcium chloride as cross linking agent. Objective: To formulate a system to remain in the stomach for prolonged and predictable period in order to enhance the drug bioavailability. Method: They were evaluated for micromeritic study, percentage yield, drug entrapment efficiency, in-vitro buoyancy, surface morphology, in-vitro drug release, in-vivo floating study and stability studies. Results: The micromeritic parameters of floating microspheres were found to be within the acceptable limits. The particle size of microspheres containing HPMC K4M was found to be in the range 85-312 mu m and that of ethyl cellulose containing microspheres was in the range of 167-329 mu m. The entrapment efficiency was found to be in the range of 61.5%-79.0%. The floating microspheres were spherical in shape with distinct pores, slightly rough surface when observed under scanning electron microscopy. The percentage yield was found to be in the range of 75%83.72%. The in vitro buoyancy was found to be in the range of 67.3%-87% and a total buoyancy time of more than 10 h. The in vitro dissolution studies showed a cumulative % release in the range of 57.15%-87.43%. The optimized formulation F4 was floating in rabbit stomach for almost 8 h. All the formulations followed Korsemeyer-Peppas kinetics indicating drug release by non-fickian release mechanism. The stability studies showed that floating microspheres were stable at 40 +/- 2 degrees C. Conclusion: The optimized formula-tion showed good floating for 8 h in stomach of rabbit. The formulation was stable at the end of 60 days with stability study.