DEVELOPMENT OF FOUR UV-SPECTROMETRIC TECHNIQUES FOR CONCURRENT ESTIMATION OF ASPIRIN AND SILDENAFIL CITRATE IN THEIR BINARY MIXTURE AND PHARMACEUTICAL FORMULATIONS

Abstract

The combination of aspirin (ASP) and sildenafil citrate (SIL) into single dosage form has been of interest for a considerable period; because it has a synergistic effect for the handling of many diseases. Therefore, UV-spectrometric techniques were desperately required for the concurrent estimation of ASP and SIL in their binary mixture and pharmaceutical formulations. In this paper, four simple, low-cost and precise UV-spectrometric techniques were evolved for the concurrent estimation of ASP and SIL. The advanced methods include treatment of the zero-order spectrum by ratio subtraction (RS) along with spectrum subtraction method (SS), absorption correction method (ACM), area under the curve correction method (AUCCM) and induced dual wavelength method (IDWM). Moreover, UV-spectrometric purity analysis via spectral ratio factor (SRF) was developed; which considered the first UV-spectrometric purity testing to verify the purity of ASP in pharmaceuticals formulations. All approaches were linear; in the range of 25.0-100.0 μg/mL for ASP, and 10.0-50.0 μg/mL for SIL. The mean percentage recoveries for ASP were 100.92, 100.33, 100.79 and 100.18% respectively, and for SIL were 99.27, 99.56, 99.83 and 99.44% respectively. The SRF values were approximating unity and showed high purity of the resolved peaks. The results were statistically compared with the HPLC reported method and no significant variance was discerned.