Development and Validation of Three Spectrophotometric Methods for Determination of Cyclobenzaprine Hcl in The Presence of its Two Major Degradation Products

Abstract

Accurate, precise, simple, selective and validated three spectrophotometric methods were established for analysis of Cyclobenzaprine Hcl (CZ) in presence of its two major oxidative degradation products; Dibenzocycloheptatrienone (DZ) and Anthraquinone (AQ), in its pure form and in its pharmaceutical formulation. Method A is double devisor ratio spectra spectrophotometric method (DDR), which is based on dividing the absorption spectrum of CZ by spectrum of the mixture which has similar concentrations of DZ and AQ (2μg/ml of each), then the peak amplitude of the first derivative spectra (1D) of CZ was measured at 216.6 nm. Method B is modified ratio difference method (MRD) which relies on dividing the absorption spectra of CZ by the standard spectrum of (6μg/ml) AQ to give the division spectra. The variance in values of amplitude of the division spectra at 219.9 and 278.8 nm (corresponding to zero difference of DZ) is then measured. Finally, method C is mean centering of ratio spectra (MCR) of CZ which based on implementation of the mean centered ratio spectra in two consecutive steps and measuring the mean centered values of the second ratio spectra at 303 and 377 nm.