Spectrofluorimetric Determination of Chlorpromazine Hydrochloride and Thioridazine Hydrochloride

Flow injection potentiometric determination of chlorpromazine

New chlorpromazine selective electrodes with a tubular arrangement and no internal reference solution are proposed. Selective membranes are of poly(vinyl chloride) (PVC) with the tetraphenylborate.chlorpromazine (TPB.CPZ) ion-exchanger dissolved in o-nitrophenyl octyl ether (oNPOE). Analytical features of the electrodes were evaluated on a single-channel flow assembly having 500 microl injection volumes and flow-rates of 4.5 ml min(-1). For a carrier solution of 3.3 x 10(-3)M in sodium sulphate, Nernstian response was observed over the concentration range 1.0 x 10(-5) to 1.0 x 10(-2)M. Average slopes were about 59 mV decade(-1) and squared correlation coefficients were >0.9984. Slight hiper-Nernstian behaviour was observed in buffer solutions of 4.4 pH; average slopes were of 62.06 mV decade(-1). The electrode displayed a good selectivity for CPZ, with respect to, several foreign inorganic and organic species. The selective electrodes were successfully applied to the analysis of pure solutions and pharmaceutical preparations. Proposed method allows the analysis of 84 samples h(-1), producing wastewaters of low toxicity. The proposed method offers the advantage of simplicity, accuracy, applicability to coloured and turbid samples, and automation feasibility.

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.

Determination of some psychotropic phenothiazine drugs by charge-transfer complexation reaction with chloranilic acid

A spectrophotometric method is described for the determination of four commonly used psychotropic phenothiazine drugs. The method is based on the measurement of the intensely coloured charge-transfer complex formed by the interaction of these drugs as n-electron donors with chloranilic acid as the pi-acceptor. The coloured species measured exhibits maximum absorption at 535 nm. The molar-combining ratio and optimum assay conditions are reported. Beer's law is obeyed over the range, 25-250 microg ml(-1) with apparent molar absorptivity in the range, 0.93 x 10(3)-1.45 x 10(3) l mol(-1) cm(-1). The limits of detection and quantification are reported. The proposed method was applied to the determination of these psychotropics in pharmaceutical formulations and the results demonstrated that the method is equally accurate, precise and reproducible as the official methods. The validity of method was established by recovery studies via standard-addition technique with satisfactory results.

Application of potassium dichromate and iron-thiocyanate in the spectrophotometric investigations of phenothiazines

A spectrophotometric procedure for the determination of phenothiazines in pure form and in a number of their pharmaceutical preparations has been developed that offers the advantages of simplicity, accuracy, precision and sensitivity over many other methods. The method is based on the oxidation of phenothiazines by a known excess amount of potassium dichromate followed by the estimation of unreacted amount of dichromate by reacting with excess of iron(II) and measuring the iron(III) formed by complexing with thiocyanate. The reacted oxidant corresponds to the drug content. Different variables affecting the reaction between drugs and dichromate were studied and optimized. At the maximum absorption of 480 nm, Beer's law is obeyed in the range 2.5-29.75 microg/ml. The molar absorptivity and Sandell sensitivity of the procedure were calculated in addition to detection limit. Statistical treatment of the experimental results indicates that the procedure is precise and accurate. Excipients used as additives in pharmaceutical formulations did not interfere in the proposed procedure. The reliability of the method was established by parallel determination against the official BP methods. The procedure described was successfully applied to the determination of the bulk drugs and in pharmaceutical formulations.

Quantitation of pharmaceutically important phenothiazines by oxidimetry

A new spectrophotometric method for the assay of phenothiazines in pure form as well as in pharmaceutical formulations with the chromium(VI)-metol-sulfanilic acid system has been developed. The method is based on the oxidation of the drugs by a known excess of chromium(VI) and subsequent determination of the unreacted oxidant by interacting with metol and sulfanilic acid. The reacted oxidant corresponds to the drug content. The coloured species exhibits maximum absorbance at 530 nm. Beer's law is obeyed over the concentration range 5-60 micrograms ml-1 and the relative standard deviation is found to be less than 2%. The apparent molar absorptivities are in the range 3.77 x 10(3)-3.98 x 10(3) l mol-1 cm-1, the detection limits being in the range 0.6133-1.1349 micrograms ml-1. The method was successfully applied to the determination of the studied drugs in their formulations and the mean percentage recoveries were found to be 97.32-102.80%.