Novel extractive visible spectrophotometric method for determination of antihypertensive drug irbesartan with sulfonephthalein acid dyes in tablets

Irbesartan (IRB) is one of the drugs used for the treatment of hypertension. The present work develops and validates two methods for the evaluation of irbesartan in bulk and tablets. Sulfonephthalein acid dyes, bromophenol blue (BPB), and bromocresol purple (BCP) were used to produce stable yellow ion-association complexes with the basic drug IRB in dry chloroform. The colored products are quantified spectrophotometrically at their corresponding λmax. The relation between the absorbed signal and the drug concentration was linear up to 45.0 μg mL-1 (n = 6, r ≥ 0.9998). LOD reaches 40 ng mL-1. The composition of the ion associates was found 1:1 by Job’s and mole ratio methods. Application of the suggested methods to dosage forms is presented with percentage recoveries ranging from 99.33% to 101.67%. The results of the analysis were validated statistically and compared with the official method. No interference was observed from common pharmaceutical adjuvants.