Validated TLC Method for Simultaneous Quantitation of Amlodipine Besylate and Valsartan in Bulk Drug and Formulation

This paper describes a new, simple, precise, and accurate TLC method for simultaneous quantitation of amlodipine (AML) besylate and valsartan (VAL) as the bulk drug and in tablet dosage forms. Chromatographic separation of the drugs was performed on aluminum plates precoated with silica gel 60 F(254) as the stationary phase and the solvent system consisted of toluene: methanol: acetic acid 7: 3: 0.1 (v/v/v). Densitometric evaluation of the separated zones was performed at 244 nm. The two drugs were satisfactorily resolved with R(F) values of 0.41 +/- 0.02 and 0.54 +/- 0.02 for AML and VAL, respectively. The accuracy and reliability of the method was assessed by evaluation of linearity (100-600 ng spot(-1) for AML and 1,600-9,600 ng spot(-1) for VAL), precision (intra-day RSD 1.51-1.83% and inter-day RSD 1.24-1.95% for AML, and intra-day RSD 0.14-0.39% and inter-day RSD 0.19-0.52% for VAL), accuracy (98.29 +/- 1.16% for AML and 98.72 +/- 0.50% for VAL), and specificity, in accordance with ICH guidelines.