Simultaneous Spectrophotometric Determination of Valsartan and Ezetimibe in Pharmaceuticals
Purpose: To develop a direct, simple and extraction-free spectrophotometric method for the simultaneous estimation of valsartan and ezetimibe in pharmaceuticals.
Methods: A spectrophotometric method for the determination of valsartan and ezetimibe was developed using acidic dyes, namely, bromophenol blue (BPB) and bromocresol green (BCG). The method was based on selective ion-pair formation between valsartan and the acidic dye. The yellow coloured ion-pair induces a bathochromic shift in the spectrum with maximum absorbance at 425 and 428 nm for BPB and BCG, respectively. The developed method was validated as per ICH guidelines.
Results: With BPB, the ion-pair formed obeyed Beer`s law in the ranges 5 - 40 and 1 - 50 μg/mL for valsartan and ezetimibe, respectively. The assay data for valsartan and ezetimibe were, 99.39 ± 0.53 and 98.17 ± 0.91 %, respectively, for the commercial formulation, and 99.41 ± 0.48 and 98.16± 0.89 %, respectively, for the developed formulation. The method was validated and the correlation coefficient for valsartan and ezetimibe were 0.995 and 0.999, respectively. Recovery was in the range 99.3 - 100.3 %.
Conclusion: The proposed method is reproducible, accurate, robust and suitable for the simultaneous quantitative analysis of the studied drugs in bulk and dosage formulation.
Keywords: Valsartan, Ezetimibe, Bromophenol blue, Bromocresol green, Spectrophotometric method