Development of a densitometric method for the determination of cephalexin as an alternative to the standard HPLC procedure

A HPTLC-densitometric method was developed in order to obtain a reliable procedure for routine analysis of cephalexin in pharmaceutical formulations. Optimization of TLC conditions for the densitometric scanning was reached by eluting HPTLC silica gel plates in an horizontal developing chamber. Quantitation of cephalexin was performed in single beam reflectance mode by using a computer-controlled densitometric scanner and applying a five-point calibration. A linear regression has been found in the 200-1000 ng range. The setup method is precise, reproducible and accurate. Recovery was also assessed by comparison with the HPLC USP XXIII alternate method. In this case HPTLC-densitometry appears worth of consideration as being relatively inexpensive and time-saving (up to 12 samples can be determined simultaneously in less than 15 min with a solvent consumption of about 15 mi). The results suggest that the proposed method may be used in place of HPLC for the routine quantitation of cephalexin in both pure and dosage forms. (C) 1998 Elsevier Science B.V. All rights reserved.