FORMULATION AND EVALUATION OF GASTRO RETENTIVE FLOATING MICROBEADS OF SUMATRIPTAN

Sumatriptan is a potent and selective 5-hydroxytryptamine agonist. It is an effective agent in the treatment of acute migraine attack. Sumatriptan is rapidly but incompletely absorbed following oral administration and undergoes first pass metabolism resulting in a low absolute bioavailability of 15%. The biological half-life of Sumatriptan is about 2.5 hr.. The aim was to develop gastro retentive floating microbeads which improve the absolute bioavailability of Sumatriptan by avoiding the presystemic metabolism and thereby to reduce the dose frequency. Drug and polymer compatibility was studied by subjecting physical mixtures of drug and polymers to FTIR spectrophotometry, capability of floating in the gastric condition was evaluated. The beads were prepared by Ionotropic gelation method. By using Sodium alginate, hydroxyl propyl methylcellulose K4M and Guar gum grade in 1:1, 1:2, 1:3 ratios. The beads were evaluated for percent drug entrapment efficiency, and in vitro drug release. The in vitro drug release study of the beads was carried out in simulated gastric media by USP dissolution method. Beads formulated employing Sodium alginate alone could not sustain the drug release, whereas beads formulated with mixture of Sodium alginate and copolymers demonstrated sustained release of Sumatriptan for 12h.