CHARGE TRANSFER COMPLEX FORMATION FOR DETERMINATION OF SOME THIOXANTHENE DERIVATIVES BY RHODAMINE B PART: 11

A simple and highly sensitive method is proposed for the spectrophotometric determination of three thioxanhene derivatives, namely: chlorprothixene, flupentixol and thiothixene, in pure forms and in pharmaceutical preparations, based on the charge-transfer (CT) complex formation between rhodamine B as an acceptor and thioxanhene derivatives as donors in acetate buffer (pH 4 ). The results obtaind compare favourably with those obtained by the official methods. The factors affecting the formation of the CT- complex were studied, linear calibration graphs were obtained in the concentration range 1.269- 20.301 μg/ml in water, 1.269-17.740 μg/ml in acetonitrile and 1.269-17.740 μg/ml in ethanol at 25°C. The same complexes have been studied in the same media for conductometric measurements. The method could be successfully adopted for pharmaceutical preparations.The molar conductivity coefficients were found to increase with increasing temperature (25-35°C) in all the systems studied. The stoichiometry of the thioxanhene derivatives-rhodamine B complexes was found to be 1:1 in both techniques.