Pellets were prepared from wet granulations using an extruder and spheronizer. Binary mixtures of active ingredient and different types of Avicel micro-crystalline cellulose products have been processed and evaluated to determine the effect of varying the drug, the diluent, and the drug-diluent ratio. Physical properties including in-vitro drug release profiles were evaluated for the uncoated pellets. Anhydrous Theophylline, USP and Quinidine Sulfate, USP were evaluated at drug-diluent ratios from 10:90 to 80:20. Chlorpheniramine Maleate, USP and Hydrochlorothiazide, USP were incorporated into one system to study the influence of more extreme values of aqueous solubility on drug release. Drug release was found to vary with the drug, diluent, and the drug-diluent ratio.