Thin-layer chromatographic identification of phenothiazine derivative drugs

Data are presented on the thin-layer chromatographic identification of 20 phenothiazine bases official in the U.S.P. XX. On the basis of four chemically different solvent systems and the color developed with a spray reagent, all phenothiazines could be distinguished from each other. For greater precision, relative RF values (ratios of the RF of each phenothiazine to the RF of chlorpromazine) have been used. The relative efficiencies of various brands of commercially prepared thin-layer plates were evaluated for these solvent systems.