Two novel spectrophotometric methods for determination of ternary mixture used as antihypertensive therapy in combined tablet dosage formulation

Aim: To develop and validate two novel spectrophotometric methods for the simultaneous determination of ternary mixture of Olmesartan medoxomil, Amlodipine besylate and Hydrochlorothiazide. Methods: The proposed methods, successive ratio derivative method and double divisor method involved treatment of normal absorption spectra of ternary mixture in UV probe software for the simultaneous determination of Olmesartan medoxomil, Amlodipine besylate and Hydrochlorothiazide in bulk and tablet dosage formulation without prior separation. Results: All the drugs exhibited good linearity over the reported concentration range with acceptable correlation coefficient. The method was validated according to ICH guidelines for evaluation of accuracy, repeatability, reproducibility, sensitivity showing acceptable percent relative standard deviation of less than 2. Conclusion: The proposed methods demonstrated that these are simple, rapid, accurate and precise methods and can be used for routine analysis of bulk and tablet dosage formulation in quality control laboratories eliminating the need of prior separation of the pharmaceutical mixtures.