Fluorometric determination of some thioxanthene derivatives in dosage forms

A simple, highly sensitive method is presented for the determination of five pharmaceutically important thioxanthene derivatives, namely chlorprothixene, thiothixene, methixene hydrochloride, clopenthixol hydrochloride and flupentixol hydrochloride. The method involves the use of hexaamminecobalt(III) tricarbonatocobaltate(III) (HCTC) as an oxidant in aqueous sulphuric acid medium to induce fluorescence. The proposed method has been further applied to the determination of the five compounds in their dosage forms. The results compare favourably with those obtained by the official methods.