Simultaneous determination of promethazine, chlorpromazine, and perphenazine by multivariate calibration methods and derivative spectrophotometry.

Partial least-squares (PLS) regression, singular value decomposition-based PLS, and an artificial neural network (ANN) were tested as calibration procedures for the simultaneous determination of promethazine, chlorpromazine, and perphenazine by both conventional and derivative spectrophotometry. Comparison of the results revealed that the application of the ANN to the derivative spectra is superior to the application of the 2 PLS methods used. Different binary and ternary synthetic mixtures of the phenothiazine drugs in pure form and in tablets were analyzed by the proposed method, and acceptable results were obtained.