Rapid analysis of adulterated sildenafil citrate in marketed herbal aphrodisiacs using infrared spectroscopy

Abstract

A simple, rapid, non-destructive and cost-effective FTIR spectroscopy in combination with multivariate calibration of Stepwise Multiple Linear Regression (SMLR) has been developed for quantification of sildenafil citrate in marketed herbal aphrodisiacs. Selecting the best wavenumbers capable of providing the high coefficient of determination (R2), low values of Root Mean Square Error of Calibration (RMSEC) and predictive residual error sum of squares (PRESS) was the main point in this study. Finally, wavenumbers 1791, 1692, 1691 and 971 cm−1 were selected for prediction of sildenafil citrate in the marketed herbal aphrodisiacs. The correlation between actual values of sildenafil citrate determined in marketed herbal aphrodisiacs using FTIR spectroscopy combined with SMLR at 1791, 1692, 1691 and 971 cm-1 revealed R2 values of 1.00. The RMSEC values obtained are 0.000310913. The PRESS value obtained as the results of cross-validation model selection for sildenafil citrate in marketed herbal aphrodisiacs is 0.0009191. The high value of R2 and low value of RMSEC and PRESS indicated this method has high accuracy and precision in validated condition for quantification of sildenafil citrate in marketed herbal aphrodisiacs. These results indicated that FTIR spectroscopy combined with SMLR can be an alternative method for determination of sildenafil citrate in marketed herbal aphrodisiacs.