The Use of Internal Standard Method for Dertvative-Spectrophotometric Determination of Chlorpromazine Hydrochloride

ABSTRACT The use of 1, 10-phenantroline as internal standard (IS) is proposed for spectrophotometric determination of chlorpromazine hydrochloride in pharmaceutical formulations. The spectra of both compounds: analyte and internal standard are partially overlapped, so the Savitzky-Golay alghoritm was used to obtain separated signals of analyte and IS. The best parameters to generate the second-derivative spectra were: ∠λ = 10 nm (5 experimental points) and second polynomial degree. For quantification of chlorpromazine in pharmaceuticals, the zero-crossing technique was used. The values of the second-derivative peaks were measured for chlorpromazine at 256 nm and at 236 nm for IS. Analytical characteristic for proposed method was evaluated (r2=0.9990, detection limit=3.97 ng/ml). The obtained analytical results were in good agreement with results obtained using the UV-spectrophotometric Blazek method.