The objective of the present study was to investigate the influence of polymer level and type of some hydrophobic polymers, Dammar gum and Copal gum with meltable carriers such as Poly ethylene glycol 6000 (PEG 6000) and carnauba wax, on the release rate and mechanism of lamivudine (LM) from matrix tablets prepared by hot- melt granulation technique. The granules were subjected to pre compression parameters like angle of repose, compressibility index, hausner’s ratio. Drug and polymer interactions were determined by FTIR and DSC studies. The tablets were evaluated by various physical properties such as weight variation, hardness, friability and drug content. The USP paddle method was selected to perform the dissolution profile in 900ml of 0.1 N HCL for first 2 hrs and next in 6.8 pH phosphate buffer. The release kinetics and mechanism of drug release of all the formulations by regression coefficient analysis and peppas exponential release model equations indicated that diffusion along with erosion could be the mechanism of drug release. The results of the dissolution study indicated that formulations LF8, LF9 showed the maximum drug release upto 24 hrs; where as other formulations extended the drug release upto 12hrs. Statistically significant differences were found among the drug release profile from different classes of polymeric matrices. Higher the polymeric content in the matrix decreased the release rate of drug because of increased tortuosity and decreased porosity.
