Cephalexin-Direct Compression Excipients: Preformulation Stability Screening Using Differential Scanning Calorimetry

Abstract
Differential scanning calorimetry was used as a screening technique for assessing the compatibility of cephalexin with some of the direct compression excipients. Cephalexin was found to be compatible with Avicel PH 101, Avicel PH 105, Elcema F 150, Elcema G 250, Solka-floc BW 100, Sta-Rx 1500 and Cab-0-Sil, while incompatible with Emdex, Brownex sugar, sorbitol, mannitol, granular mannitol, dicalcium phosphate dihydrate, Di-Tab and Emcompress. Cephalexin appears to interact with Di-Pac after its melting transition. It appears that L-(-)-leucine can be used as lubricant in formulations containing cephalexin while stearic acid and magnesium stearate cannot.