Crystal products of lamotrigine-citric acid for improvement of in vitro drug release in simulated gastric fluid

Abstract

Crystal engineering is an integral part of the drug development research. Crystal forms can modify the physicochemical properties of the parent drug molecule. The present work was aimed at the synthesis and characterization of crystalline product of lamotrigine (LT), an U.S. Food and Drug Administration approved anti-epileptic drug, with citric acid (CA) to improve its release in gastric region and oral absorption. The crystalline products of LT?CA were developed by solvent evaporation method using ethanol-water as the solvent system. Appearance of new characteristic peaks in the FTIR spectra for the crystal products indicated formation of new crystal state. In DSC thermogram, melting point of the experimental crystal products was different than that of the pure drug. Further, formation of new crystalline phase was confirmed from XRD data through the identification of new sharp peaks for the selected crystal products. A higher cumulative percentage of drug release was observed for the crystal products than for the free drug within 60 min of drug release in simulated gastric fluid. However, in vivo studies are warranted for the future technology transfer of the product at industrial scale.