Quantitative determination of Dapoxetine Hydrochloride and Tadalafil using different validated spectrophotometric methods.

Three rapid, simple and selective spectrophotometric methods were developed for determination of Dapoxetine Hydrochloride (DAP) and Tadalafil (TAD) in bulk and pharmaceutical dosage forms. Method (A) is simultaneous first derivative (1D) spectrophotometric method in which the peak amplitudes of the first derivative spectra (1D) were measured for both DAP and TAD at 322.4 nm and 230 nm, respectively with no interference from each other. Method (B) is the area under curve (AUC) spectrophotometric method in which the areas under curve in the wavelength ranges 228-240 nm and 242-254 nm are used for determination of DAP and TAD respectively. Method (C) is ratio subtraction combined with extended ratio subtraction spectrophotometry (EXRS) in which TAD was determined by dividing the mixture spectra by the spectrum of 15 μg/mL solution of DAP, while DAP was be determined by dividing the mixture spectra by the spectrum of 30 μg/mL solution of TAD. The developed methods were applied to different laboratory prepared mixtures of DAP and TAD. These methods were validated according to the ICH guidelines with respect to linearity, accuracy, precision, selectivity and specificity, and can be used for routine quality control analysis of DAP and TAD in their dosage forms.