Voltammetric Determination of Thioridazine Hydrochloride

Thioridazine hydrochloride, a member of the phenothiazine group, is one of the most widely used drugs in the treatment of psychiatric patients. It has a tranquilizing effect, but no therapeutically significant anti-emetic or hypothermic effect, which other phenothiazine drugs have, and does not potentiate the action of anestetics. Thioridazine is used mainly in the treatment of schizophrenia and the control of mania and agitation. It may be used in the management of anxiety states, children who have behavior problems. In thioridazine hydrochloride [(Tz-HCl)-[10-2-(1-methyl-2-piperidyl)ethyl]-2-(methylthio)phenothiazine monohydrochloride] the piperidyl group has important tranquilizing effects (Figure 1). Thioridazine hydrochloride can be determined by various techniques, including chromatography1−13 , spectroscopy , titrimetry and electrochemical18−23 methods. Thioridazine has two S atoms in the structure which can be easily oxidized, one in the ring and the other in the side chain. Since Ring-S-oxidation is an important step in the metabolism of phenothiazine drugs in man, extensive studies have been done on the oxidation mechanism of this group. In recent studies, RuO2 has been of considerable interest as an effective electrocatalyst for certain electrooxidation reactions. In our previous studies, electro-oxidation of phenothiazines were investigated with Ru and Pt electrodes22−25 . The surface of a solid electrode changes with time due to adsorption of species