Abstract

In this work, a numerical method, based on the use of spectrophotometric data coupled to partial least squares, multivariate calibration is evaluated for the simultaneous determination of olmesartan medoxomil and hydrochlorothiazide in bulk and tablet dosage form. Tablet Olmetor-H (HTZ 12.5 mg and OLM 20.0 mg) was used in this study. The equipment used was a Ultraviolet-Visible double beam spectrophotometer with a matching pair of 1 cm quartz cell and electronic balance. Spectra of olmesartan medoxomil and hydrochlorothiazide were recorded at concentrations within their linear ranges 2.5-20 μg/ml and 4-32 μg/ ml, respectively and were used to compute a total of 25 synthetic mixtures involving 16 calibration and 9 validation sets between the wavelength range of 200 nm and 350 nm with the wavelengths intervals, lambda=3 nm in methanol. The analytical performances of these chemometric methods were characterized by relative prediction errors and recovery studies (%), and were compared with each other. The proposed method is simple, rapid and can be easily used as an alternative analysis tool in the quality control of drugs and formulation. PLS was applied successfully for the simultaneous determination of OLM and HTZ in laboratory mixtures and pharmaceutical formulation.