SPECTROPHOTOMETRIC DETERMINATION OF CHLORPROTHIXENE HYDROCHLORIDE BY PYROCATECHOL VIOLET AND CERIC(IV) IONS

ABSTRACT Two methods for the determination of chlorprothixene hydrochloride are presented. One of them employs the liability of the chlorprothixene tertiary amine group nitrogen atom to form ion-association complexes with organic compounds. The formed complex is insoluble in water but well soluble in organic solvents. This property is the base of a new extractive-spectrophotometric method for chlorprothixene determination. The second method applied the oxidation reaction of chlorprothixene by Ce(IV) ions. Chlorprothixene hydrochloride is oxidised by ceric(IV) ions at room temperature with the formation of colourless products. Both reactions were followed spectrophotometrically by measuring the absorbance at 445 nm (extractive method) and at 268 nm (oxidative method). Extractive-spectrophotometric method allows to determine chlorprothixene hydrochloride in the range of 3.5–32.0 µg/mL. The oxidative method obeys Beer's law in the range of 3.2–21.0 µg/mL. The methods were successfully applied to the determination of chlorprothixene in pharmaceutical solutions. The results are in good agreement with those obtained by the official procedure.