Chemometric spectrophotometric methods for simultaneous estimation of metoprolol succinate and amlodipine besylate in their tablet formulation

Two simple chemometric spectrophotometric methods; isosbestic point and dual wavelength methods were developed, validated and applied to the determination of metoprolol succinate in presence of amlodipine besylate in their binary mixtures and in combined tablet formulation while amlodipine besylate was determined by direct spectrophotometry at λ = 365 nm within linearity range of 2-25 μg/mL. The mean percentage recovery ± SD was 99.921 ± 0.089 for amlodipine besylate. Two proposed chemometric spectrophotometric methods were developed for the spectral resolution of metoprolol succinate in presence of amlodipine besylate without preliminary separation with a linearity range of 2-30 μg/mL metoprolol succinate. The first method depended on measuring the absorbance at the isosbestic point at λ = 226 nm. The mean percentage recovery ± SD was 100.110 ± 0.249 for metoprolol succinate. The second method was dual wavelength method, metoprolol could be determined alone using the absorbance difference between 226 nm and 248.7 nm where the absorbance difference was zero for amlodipine at these two wavelengths. The mean percentage recovery ± SD was 99.734 ± 0.438 for metoprolol succinate using dual wavelength method. The developed methods were validated as per ICH guidelines and were successfully applied to analysis of cited drugs in their synthetic tablet formulation. The results obtained by the developed methods were statistically compared to those obtained by a reported one using t-test and F- test. Good agreement was observed.

Analytical and Bioanalytical Techniques for the Quantification of the Calcium Channel Blocker - Amlodipine: A Critical Review

Hypertension is a condition in which blood pressure is elevated to an extent where benefit is obtained from blood pressure lowering. The risk of complications is proportional to the level that blood pressure raises. Calcium channel blockers are a class of compounds used in the treatment of hypertension. The dihydropyridine (DHP) group, a subclass of the calcium channel blocker works almost exclusively on L-type calcium channels in the peripheral arterioles and reduce blood pressure by reducing total peripheral resistant. Long acting DHP is preferred because they are more convenient for patients and avoid the large fluctuations in plasma drug concentration which are associated with side effects. Amlodipine is the most distinct DHP and the most popular. The drug was patented in the year 1986 and its commercial sale began by 1990. The current article provides a state of art about the analytical and bioanalytical techniques available for the quantification of drug as a single entity and in combined pharmaceutical formulations between 1989 and 2019.