Abstract

Spectrophotometric quantification of tadalafil by oxidative coupling reaction with MBTH reagent.

Author(s): Pani Kumar D.Anumolu A.Kavitha, D.Vijaya Durga, S.Hima Bindu, G.Sunitha, K.Ramakrishna

A simple and sensitive spectrophotometric method in visible region has been developed and validated for quantification of tadalafil bulk drug and pharmaceutical dosage forms. The method is based on the oxidative coupling reaction of 3-methyl-2-benzothiazoline hydrazone (MBTH) with tadalafil in the presence of ferric chloride to formgreen coloured chromogen with absorption maximum at 676 nm. BeerÂ’s law is obeyed in the concentration range of 2 – 12 µg/mL with correlation coefficient 0.999, limit of detection and quantification were 15.72 ng/mL and 52.63 ng/mL respectively.Whenmarketed tablet formulations were analyzed, the results obtained by the proposed method were in good agreement with labeled amounts. The developed method was validated statistically as per ICH guidelines. Satisfactory recovery from the spiked samples suggests no interference of any excipients present in the formulations. The developed method is simple, sensitive and can be successfully employed in routine analysis of tadalafil pharmaceutical dosage forms.