The use of chloranil for spectrophotometric determination of some tranquillizers and antidepressants.

Chlorpromazine hydrochloride, promethazine hydrochloride, promazine hydrochloride, perphenazine, thioridazine hydrochloride, chlorprothexine, opipramol hydrochloride, amitriptyline hydrochloride, imipramine hydrochloride and hydroxyzine hydrochloride are estimated in their pure state and in pharmaceutical formulations by means of the reaction of the free bases with chloranil in dioxan-ethanol medium to give a coloured product with maximal absorbance at 550 nm. The method is precise, accurate and specific and recommended for routine analysis for the drugs mentioned.