A two level four factor partial factorial design was adopted for enhancement of the Dissolution of a Biopharmaceutics Classification (BCS) Class IV drug (1,2,5,8,12,13,14,17). Design of experiment (DOE) was applied to optimize a tablet formulation of Tetrabenazine (TBZ) Tablets 25mg containing high percentage of Lactose Anhydrous, Sodium starch Glycolate, Magnesium Stearate and Strach/Lactose Ratio.The particle size distribution of Lactose Anhydrous is used as dependent variable and Sodium starch Glycolate, Magnesium Stearate and Strach/Lactose Ratio were used as independent variables for optimizing some tablets response parameters (1,2,8,12,13). Response parameters for final TBZ Tablets were percentage of TBZ dissolve at thirty minutes.The data were analyzed by means of Pareto chart, interaction of variables and quadratic response surface model. Response surfaces were generated for tablet percentage of dissolution and content uniformity required disintegration time and frability as a function of independent variables.The models were validated for accurate prediction of response characteristics and used to used to identify the optimum formulation.The results that an optimum TBZ 25mg tablets having a volume similar to commercial products can be produced by dry granulation process utilizing Lactose Anhydrous (1,2,3,9,12,13,15).