Quantitative Analysis of Two Pharmaceutical Combinations Containing Amlodipine with Either Bisoprolol or Candesartan Using Different UV Spectrophotometric Methods

Background Two fixed-dose combination tablets of amlodipine (AML) with bisoprolol (BIS) and amlodipine with candesartan (CAN) were recently approved for the treatment of hypertension. Objective Three UV spectrophotometric analytical methods were developed for the estimation of the above drugs in their combination mixtures. Methods For the AML and BIS mixture, AML was quantified directly by a zero-order spectrophotometric method at 360 nm without interference from BIS, whereas BIS was quantified by the ratio difference (RD) spectrophotometric method by calculating the difference between the amplitude values of the ratio spectra at 226 and 215 nm. For the AML and CAN mixture, AML was quantified directly by a zero-order spectrophotometric method at 360 nm without interference from CAN, whereas CAN was quantified by the first derivative of ratio spectra method by measuring the amplitude values of the derived spectra at 259 nm.BIS) Results The proposed methods were successfully applied for quantitative analysis of AML with BIS and AML with CAN in their synthetic laboratory-prepared mixtures and pharmaceutical tablets with acceptable results in terms of accuracy and precision.