Estimation of Tadalafil in Bulk and in Formulation by UV-Visible Spectrophotometry

Two simple, precise and accurate methods were developed for the estimation of Tadalafil in bulk and in formulations. In method A, UV spectra of tadalafil in methanol and water (80:20) exhibits the I max of 284.5nm. Method B is based on the formation of bluish green colored complex by the reduction of ferric ions into ferrous ions in presence of potassium ferricyanide as oxidizing agent exhibits the absorption maxima at 828 nm. Beer's law was obeyed in the concentration range of 5–30 μg/ml and 2–10 μg/ml for method A and B, respectively. The accuracy of the method was determined by recovery studies. The methods were validated as per ICH guidelines. % RSD value was less than 2%; this proved that the methods are having good recovery and reproducibility. The proposed methods are simple, rapid, precise and accurate and hence can be applied for routine quality control analysis of tadalafil in bulk and in tablet dosage forms.