Development and validation of spectrophotometric method for determination of Olmesartan, amlodipine and hydrochlorothiazide in combined pharmaceutical dosage forms

Abstract

A simple, accurate, precise, economical and reproducible method was developed for simultaneous estimation of olmesartan, amlodipine and hydrochlorothiazide in Combined Pharmaceutical Dosage Forms. The excipients in the commercial tablet preparation did not interfere with the assay. The λmax for olmesartan, amlodipine and hydrochlorothiazide were 252 nm, 360 nm and 271 nm respectively. At 360 nm, Amlodipine showed some absorbance while olmesartan and hydrochlorothiazide showed zero absorbance so that amlodipine was estimated at 360 nm. While at 252 nm and 271 nm olmesartan and hydrochlorothiazide were determine by simultaneous estimation method after eliminating the absorbent of Amlodipine at this wavelength. Linearity in concentration range of 4-28 µg/mL, for all three drugs with mean recovery of 99.7 ± 0.15, 99.2 ± 0.24 % and 99.4 ± 0.18 % for OLM, AML and HTZ, respectively. Validation of the proposed method was carried out for its accuracy, precision, and reproducibility according to ICH guidelines. Thus the present study gives an excellent method for the determination of all the three drugs in combined dosage formulation without their prior separation