Abstract

Stability-indicating methods for determination of tadalafil in presence of its degradation product

Author(s): Moataz A.Yehia, Mamdouh R.Rezk, Mohamed A.El-Sayed, Mohamed Abdel Kawy

Four different stability indicating assay methods were developed and validated for the determination of tadalafil in the presence of its degradation product. The first and second method was based on the derivative and derivative ratio spectrophotometric technique using mixture of acetonitrile andwater (1:1) as a solvent. In the thirdmethod,we used TLC-densitometric technique using high performance thin-layer chromatography plates with a developing systemconsisting of chloroform: acetone: ammonia (9:1:0.1, by volume). The fourthmethod was a high performance liquid chromatography. Separation of tadalafil from its degradate using C18 column and a mobile phase consisting ofwater: acetonitrile:methanolin the ratio of (45:35:20) at ambient temperature was achieved. The developed methods were successfully applied to the analysis of pharmaceutical formulations containing tadalafil with excellent recoveries.