Y.DEEPA*, VINAY UMESH RAO, M.SUDHAKAR Hydrophilic polymers, hydrophobic waxes, melt granulation, Fluoxetine HCl (FLX-HCL) 1229-1238 Volume 4, Issue 6 November - December 2013 The effect of two different viscosity grades of hydrophilic, hydroxy propyl methyl cellulose (HPMC K4M and K100M) and hydrophobic, Stearic Acid and Glyceryl Behenate on the in vitro dissolution of a model water soluble drug was evaluated. Fluoxetine HCl (FLX-HCL) was selected as the model drug due to its high aqueous solubility. Direct compression process was followed for the hydrophilic polymers and the melt granulation technique was followed for the wax matrix tablets. The dose of the drug (20 mg) and weight of the tablets (500mg) was maintained as constant.The wax matrix polymers are required to be used in significantly lower concentrations as compared to the hydrophilic HPMC polymers in order to control the drug release rate of a model water soluble drug like FLX-HCL.