The study was carried out to investigate the release profile of the Lamotrigine from the matrix tablets containing different particle size range of the coated granules. The polymer coated granules were prepared in Fluid bed processor using wurster technique. The granules obtained were separated for different particle size and were mixed in different ratio to formulate matrix tablets. The prepared tablets were evaluated for its hardness, weight variation, drug content, friability, swelling index and invitro dissolution studies. A kinetic model fitting studies were done to determine the type of release and release mechanism. The in vitro evaluation of each formulation is done to investigate the effect of particle size distribution of polymer coated granule on the release of the drug. The results indicated drastic changes in the release profile due to the difference in the particle size distribution The F5, which has the highest percentage of particles in the range of 600-800 microns has the highest release when compared to all the other batches. F3 which has the highest percentage of the particles in the range of 100 – 250 microns has the lowest release profile. The order of time taken for 90 % of the drug release can be written as F3 > F4 >F2>F1 >F5. Statistical studies like ANOVA and LSD were performed to find out the significance difference in the drug release. The goodness of fit using R2and MSC revealed that all the formulation exhibited zero order release from the matrix.
