A validated spectrofluorimetric method for determination of some psychoactive drugs

Five psychoactive drugs namely, chlorpromazine HCl, thioridazine HCl, clomipramine HCl, imipramine HCl and desipramine HCl were analyzed by a simple spectrofluorimetric method. The method is based on oxidation of the studied drugs using cerium(IV) in presence of sulphuric acid and monitoring the fluorescence of the formed cerium(III) at lambda(ex.) = 254 nm and lambda(em.) = 355 nm. All variables affecting the reaction conditions such as; cerium(IV) concentration, sulphuric acid concentration, heating time, temperature and dilution solvents were carefully studied. The effect of potential interference due to common ingredients as glucose, sucrose, lactose, citric acid and propylene glycol were investigated. A validation study of the proposed method was carried out according to USP 2002. Beer's law was obeyed for all the studied drugs in the concentration range of 0.05-1.3 microg/ml. Limits of detection range was 0.035-0.038 microg/ml and limits of quantitation of 0.116-0.125 microg/ml were obtained. The method was successfully applied for the assay of the studied drugs in pure form and in pharmaceutical dosage forms. Results were compared with official methods. The t- and F-values were calculated and compared with the theoretical values, which indicate high accuracy and good precision of the proposed method.