New Simple Spectrophotometric Method for the Simultaneous Estimation of the Mixtures of Sildenafil and some Serotonin Reuptake Inhibitors

This work presents a simple, reproducible, sensitive, generic and efficient method for simultaneous estimation. Vierordt’s method or simultaneous equation method was developed and validated for simultaneous estimation of two mixtures: Sildenafil and Duloxetine, Sildenafil and Fluoxetine, in the pure and pharmaceutical dosage form. The method was based on the measurement of absorbance at two wavelengths for each mixture in methanol. Calibration curves of all drugs were found to be linear. With good correlation coefficient values more than 0.99. The RSD values were found within limits and the recoveries ranging between 98 to 102% that confirms that the proposed method is accurate. This method for simultaneous estimation of these four mixtures is simple and economical and can be applied successfully for the simultaneous estimation of PDEs inhibitors and their combinations with some serotonin reuptake inhibitors in the pure and pharmaceuticals dosage forms.