Abstract
Differential scanning calorimetry was used as a screening technique for assessing the compatibility of anhydrous ampicillin with some of the direct compression excipients. Anhydrous ampicillin was found to be compatible with Avicel PH 101, Avicel PH 105, Elcema F 150, Elcema G 250, Sta-Rx 1500 and Cab-0-Sil, while incompatible with sorbitol, Di-Pac and dicalcium phosphate dihydrate. Anhydrous ampicillin appears to form complexes with mannitol, granular mannitol and Brownex sugar after their melting transitions. It appears that stearic acid and L-(-)-leucine can be used as lubricants in formulations containing anhydrous ampicillin while magnesium stearate cannot.