Simultaneous estimation of depoxetine hydrochloride and tadalafil as API in tablet dosage form by simultaneous equation method

Abstract

A method for the simultaneous estimation of DPX Hydrochloride and TDX in a tablet dosage form using the simultaneous equation method was developed and validated. This method relies on the different maximum absorbance wavelengths of the two drugs: DPX Hydrochloride at 210 nm and TDX at 285 nm. Calibration curves were plotted for both drugs, and the concentrations in synthetic mixtures were determined using simultaneous equations derived from the absorbance measurements at these wavelengths. The method demonstrated high accuracy, precision, and specificity, adhering to ICH guidelines. In the linearity study at respective wavelengths, the linear regression equation for DPXHydrochloride, calibration curve at 285 nm was calculated by y = 0.088x +0.005 (r² = 0.999), where y is absorbance and x is the value of various concentrations of standard solutions and the linear regression equation for Dapoxtine Hydrochloride, calibration curve at 210.0 nm was calculated by y =0.073x + 0.002 (r² = 0.999) (Table – 3). Moreover, in the linearity study at of the other API at consecutive wavelengths, the linear regression equation for TDX, calibration curve at 285.0 nm was calculated by y = 0.022x+0.035 (r² = 0.996) and the linear regression equation for TDX, calibration curve at 210 m was calculated by y = 0.034x - 0.013 (r2=0.998). The simultaneous equation method provided a reliable and accurate means of quantifying DPXHydrochloride and TDX in tablet formulations. The calibration curves were linear, and the method complied with ICH guidelines for specificity, accuracy, and precision. This method is advantageous for quality control in pharmaceutical formulations, offering simplicity and efficiency.