Development and validation of extractive visible spectrophotometric methods for determination of ropinirole hydrochloride in pharmaceutical dosage forms based on ion-association complex formation

Two simple and sensitive extractive visible spectrophotometric methods (A &B) for the assay of ropinirole hydrochloride in pure and dosage forms based on the formation of colored chloroform soluble ion-association associates under specified experimental conditions are described. Two dyes namely acidic dye Tropaeoline ooo (TPooo, method A), Azo carmine-G (ACG, method B) are utilized. The extracts of the ion-associates exhibit absorption maxima at 485nm and 550nm for methods A and B respectively. Regression analysis of Beer-Lambert plots showed good correlation in the concentration ranges (5.0–25) μg/ml for method A, (10–50) μg/ml for method B respectively. The proposed methods are applied to commercial available tablets and the results are statistically compared with those obtained by the UV reference method and validated by recovery studies. The results are found satisfactory and reproducible. These methods are applied successfully for the estimation of the ropinirole hydrochloride in the presence of other ingredients that are usually present in dosage forms. These methods offer the advantages of rapidity, simplicity and sensitivity and low cost and can be easily applied to resource-poor settings without the need for expensive instrumentation and reagents.