FORMULATION AND EVALUATION OF SINTERED MATRIX TABLETS OF LAMOTRIGINE

Extended release dosage form of lamotrigine with pH dependent solubility was formulated using sintering technique. In conventional immediate release tablet the pharmacokinetic profile shows peak concentration causing adverse effects and troughs causes breakthrough seizures. Hence the matrix tablets were prepared using controlled release natural and synthetic polymers such as HPMC K4M, HPMC K15M, HPMC K100M, acacia, guar gum and xanthan gum. The polymers were used in 1:2, 1:3, and 1:4 ratios and compressed by direct compression method. Dissolution studies were carried out in pH 6.8 buffer with 0.5% SLS. Relatively more extended release was observed with 1:4 ratio of polymer of HPMC K15M, HPMC K100, guar gum and xanthan gum. F15, F17, F18 formulations having 1:4 ratios of drug and polymer were found to comply with U.S.P specifications of controlled release. The lowest concentration of polymer 1:2 was selected for chemical sintering and percentage release profile was calculated. Formulae F3S, F5S, F6S were found to extend the release of the drug as that of formulae with higher concentration of polymers before sintering. F6S2 has found to show zero order kinetics with Higuchi release profile at lowest sintering time, complied with U.S.P specifications. Based on the study it can be concluded that sintering technique enhances the extended release of the drug with low concentrations of polymer and it would be a cost effective method. Key Words: Matrix Tablets, Natural and synthetic polymers, Sintering technique.