Abstract

A COMPARATIVE STUDY OF DIFFERENT APPROACHES FOR STABILITY-INDICATING DETERMINATION OF ENTACAPONE IN PRESENCE OF ITS ALKALINE-INDUCED DEGRADATION PRODUCT

Khalid Abdel-Salam M. Attia, Mohammed Wafaa Nassar, Mohamed A. Hasan*

ABSTRACT

Five, simple, accurate, selective and sensitive methods were developed for the determination of entacapone in presence of its alkaline-induced degradation product without previous separation. The first method is the first derivative technique, measure peak trough of derivatized spectra at 403 nm. The second method is the first derivative of ratio spectra is used for the determination of entacapone in presence of its degradation product at 359 nm. The third method is the ratio difference technique which depends upon measuring peak amplitudes of ratio spectra at 246 and 377 nm using 7μg/ml degradate spectrum as a divisor. The fourth method is the mean centering of ratio spectra which depends upon centering data of ratios at 378 nm. The fifth method is the dual wavelength method which depends upon measuring peak amplitudes of zero order spectra at 249 and 357.6 nm. The calibration graphs were linear in the range of (1 10 μg/ml) for entacapone. The methods were validated according to International Conference of Harmonization (ICH) guidelines.

Keywords: Entacapone; First derivative; Derivative ratio; Ratio difference; Mean centering; Dual wavelength.