Non-extractive spectrophotometric determination of valsartan in pure form and in pharmaceutical products by ion-pair complex formation with bromophenol blue and methyl red

Two simple, rapid, green non extractive spectrophotometric methods are described for the estimation of valsartan in tablet dosage form. The determination is based on ion-pair formation using dyes, bromophenol blue (BPB) and methyl red (MR). Valsartan forms complex selectively with as indicated by a coloured BPB at pH 5.5 λmax 424 nm MR 4.3 494 nm. For both methods, optimal conditions were established. linear relationship was found between absorbance concentration drug range 8–24 µg/mL 4–20 MR. Regression analysis Beer’s law plot yielded regression equation, y = 0.0102x + 01636 0.0222x – 0.0063 High values correlations coefficient (R 2 0.9988 R 0.9991 (MR)) small intercept validated linearity calibration curve obedience to law. LOD LOQ calculated be 1.03 3.43 respectively 0.68 2.26 Intra-day inter-day accuracy precision, robustness acceptable limits. proposed applied quantification tablets pertaining three commercial formulations. Analytical eco-scale greenness assessment showed that corresponds excellent score 89.