[Chromatographic purity tests of various phenothiazine derivatives. I. Thin-layer chromatography]

Chromatographic purity tests of four phenothiazine derivatives chlorpromazine, levomepromazine, promethazine and trifluoperazine have been developed. The adsorptive and partition methods are suitable to the separation of the above substances and intermediates as well as side products of their productions. The most common impurities of final products were detected by qualitative purity tests. Densitometric quantitative determinations were carried out on silicagel layer using the solvent system cyclohexanebenzene-diethylamine. Quantity of intermediate impurities were 0.15-0.96%.