Spectrophotometric determination of ritonavir by condensation method using ninhydrin and ascorbic acid.

ABSTRACT

A simple and sensitive extractive visible spectrophotometric method for the assay of Ritonavir in pure and pharmaceutical Formulations based on the reaction between peptide group in RIT and Ninhydrin in the presence of ascorbic acid affords a blue violet coloured product (λ max 560nm). Regression analysis of Beer-Lambert plots showed good correlation in the concentration ranges (20-60) μg/ml. The percent recoveries are obtained as 99.64 ± 0.47 to 100.40 ± 0.45 by proposed method and 99.51 ± 0.25 to 99.92 ± 0.20 by reference method for the formulations respectively. The method can be applied successfully for the estimation of the Ritonavir in the presence of other ingredients that are usually present in formulations. The method offers the advantage of rapidity, simplicity and sensitivity and low cost without the need for expensive instrumentation and reagents.