Abstract
Three methods are developed for simultaneous determination of Miconazole Nitrate and Betamethasone valerate without previous separation. The first method depends on first derivative of the ratio spectra by measurements of the amplitudes at 230 nm for Miconazole nitrate and at 240 and 256 nm for Betamethasone valerate. The second method depends on measuring the absorbance at the isosbestic point at 231.5 nm for the total concentration of both drugs while the concentration of Betamethasone valerate is determined by direct spectrophotometric method at λ max 250 nm in the presence of Miconazole nitrate, the concentration of Miconazole nitrate is calculated by subtraction. The third method involved application of the bivariate calibration algorithm for spectrophotometric simultaneous determination of the mixture. The zero-order spectra of standard drugs are found to be overlapped making their simultaneous determination difficult but applying the proposed methods to the spectral data of the mixture, both MIC and B-Val concentrations could be determined without any interference.All the proposed methods were validated. They have the advantage of being economic and time saving and can be readily utilized for the analysis of pharmaceutical formulations. The results obtained by the proposed methods were statistically analyzed and compared with those obtained by reference methods.