Spectrophotometric Analysis of some Phenothiazine Neuroleptics using Chloramine-T

Ion-pair complex-based solvent extraction combined with chemiluminescence determination of chlorpromazine hydrochloride with luminol in reverse micelles

A new chemiluminescence (CL) method is proposed for the determination of chlorpromazine hydrochloride, which is based on the dichloromethane solvent extraction of ion-pair complex of tetrachloroaurate(III) with chlorpromazine hydrochloride and luminol chemiluminescence detection in a reversed micellar medium formed by the cation surfactant cetyltrimethylammonium bromide in a dichloromethane-cyclohexane (1:1 V/V)-water (0.3 mol/L Na2CO3 buffer solution with the pH of 11.5). The ion-pair complex of tetrachloroaurate(III) with chlorpromazine hydrochloride produced an analytical chemiluminescence signal when it entered the reversed micellar water pool. In the optimum conditions, CL intensities are proportional to concentrations of the studied drug over the range 0.05 approximately 10 microg/mL with a detection limit (DL) of 6 ng/mL. The relative standard deviation (R.S.D.) is 2.6% for 1.25 microg/mL chlorpromazine hydrochloride (n = 11). R.S.D. (precision) of inter-day and intra-day is less than 6%, and accuracy of inter-day and intra-day is satisfactory. The method has been applied to the determination of studied drug in pharmaceutical preparations and biological fluids with satisfactory results.

Spectroelectrochemical determination of chlorpromazine hydrochloride by flow-injection analysis

An original, simple and sensitive flow-injection spectroelectroanalytical method for the determination of chlorpromazine in pure form or in pharmaceutical formulations is described. The method is based on the formation of a stable cationic radical by electro-oxidation in sulfuric acid medium (0.1 mol l(-1)), monitored in situ at lambda=524 nm. The determination of chlorpromazine hydrochloride in pure form or in pharmaceutical formulations was explored, considering the amperometric and the absorptiometric signal. The association of these two signals enhanced the selectivity of the analysis and proved decisive when other electroactive compounds or excipients like ascorbic acid were present in the formulation. The analytical parameters have been evaluated and the results obtained using standard additions are in agreement with the reference methods.

A Novel Spectrophotometric Determination of Some Phenothiazines Involving Iodine monochloride from Chloramine-T with Iodine

A novel, simple, sensitive spectrophotometric method is proposed for the determination of five phenothiazines. Chloramine-T with iodine in acetic acid produces iodine monochloride which oxidizes phenothiazines to absorbing cations. Those would associate later with unreacted ICl to form an ion pair, [Ph+] [ICl-(2)] in hydrochloric acid medium. These appear to provide exceptional color stability to the systems. A probable mechanism along with experimental stoichiometry and stability constants of such ion pairs is indicated. The method is not only successful in stabilizing the color of the systems, but also in making a unique observation of two regions of concentration of phenothiazines adhering separately to Beer's law. The results obtained from the analyses of pure samples and their drug formulations in both regions of concentration are comparable with those obtained either with a reported titrimetric method or with a British Pharmacopoeia (B.P.) UV-spectrophotometric method. The conditions required for the quantitative determination of phenothiazines are described and related analytical parameters are also calculated.

Bead injection spectroscopy-flow injection analysis (BIS-FIA): an interesting tool applicable to pharmaceutical analysis

A bead injection spectroscopy-flow injection analysis (BIS-FIA) system for the spectrophotometric detection of promethazine and trifluoperazine is developed. The sensor is based in the oxidation of the phenothiazines by Fe(III) which is later determined by formation of the complex between Fe(II) and Ferrozine, [FeFz(3)](4-). Immediately, this complex is retained on a homogeneous bead suspension of Sephadex QAE A-25 resin (500 microl) which has been injected previously in the system to fill a commercial flow-cell (Hellma 138-OS). The use of BI with respect to the use of a reusable flow-through sensor is justified because the complex is so strongly retained on the beads that the regeneration of the solid support becomes extraordinarily difficult in the proposed method. At the end of the analysis, beads are automatically discarded from the flow-cell, by reversing the flow, and transported out of the system. The analytical signals are measured at a wavelength of 567 nm, corresponding to the absorbance of the complex. Using a sample volume of 600 microl, the analytical signal showed a very good linearity in the range 0.5-8.0 microgml(-1) and 0.5-10.0 microgml(-1), with detection limits of 0.09 and 0.14 microgml(-1) for promethazine and trifluoperazine, respectively. R.S.D.s (%) lower than 2% were obtained for both analytes. The proposed method is highly selective in the presence of other species that are normally encountered with these analytes. The sensor was satisfactorily applied to pharmaceutical preparations.

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.

Two simple methods for the estimation of albendazole and its dosage forms using chloramine-T

Two simple, rapid and reliable methods for the determination of albendazole are described. Both methods involve the use of chloramine-T as the oxidimetric reagent. In the titrimetric method, a known excess of chloramine-T is added to an acidified solution of sample, and after a specified time, the residual oxidant is determined iodometrically. Spectrophotometric procedure also involves the addition of a measured excess of chloramine-T in buffer medium of pH 2.70+/-0.1 and after the reaction is ensured to be complete, the surplus oxidant is determined by a well established colour reaction involving metol and primary arylamine that results in charge-transfer complex measurable at 520 nm. In both methods, the amount of chloramine-T corresponds to the drug content. Reaction conditions were examined and optimised. Titrimetry is based on a 1:3 stoichiometric reaction between albendazole and chloramine-T and is applicable in the range of 1-15 mg. In spectrophotometry, the absorbance was found to decrease linearly with increasing concentration of albendazole, which is corroborated by the calculated correlation coefficient value of -0.9998. The system obeys Beer's law for 2.5-25 microg x ml(-1) of albendazole. The molar absorptivity and Sandell sensitivity were calculated to be 6.24 x 10(3) l mol(-1) cm(-1) and 42.54 ng cm(-2), respectively. The limits of detection and quantification were calculated to be 1.15 and 3.83 microg x ml(-1), respectively. The proposed methods were successfully applied to the determination of albendazole in commercially available dosage forms. The reliability of the assays was established by parallel determination by the official method and recovery studies.

Use of an oxidation reaction for the quantitative determination of albendazole with Chloramine-T and acid dyes

One titrimetric and two spectrophotometric procedures have been reported for the determination of albendazole and its tablets. Using titrimetry, the drug was titrated directly with Chloramine-T under acidic conditions using a Methyl Orange indicator. The spectrophotometric procedures involve treating the sample solution with a measured excess of Chloramine-T in an acid medium, followed by an estimation of unreacted Chloramine-T by reacting with a fixed amount of either Methyl Orange or Indigo Carmine dye solution and measuring the absorbance at 510 nm or 610 nm. The stoichiometric ratio, which forms the basis for the calculations in titrimetry as well as the range of the applicability, are reported. The Beer's law range and sensitivity values for spectrophotometric procedures are included. The methods were applied to the determination of albendazole in tablets with satisfactory results.

A highly sensitive spectrophotometric method for the determination of some phenothiazine antipsychotics using chloramine-T and indigocarmine

A new simple, accurate and precise spectrophotometric method for the determination of six phenothiazine drugs in pure form and in dosage forms is described. The method is based on the oxidation of the studied drugs by a known excess of Chloramine-T in hydrochloric acid medium and subsequent determination of the unreacted oxidant by reacting it with indigocarmine in the same acid medium. The reacted oxidant corresponds to the drug content. The colored species exhibits maximum absorption at 610 nm. The apparent molar absorptivity values and Sandell sensitivity values are in the range 1.53 x 10(4)-2.96 x 10(4) l mol-1 cm-1 and 13.75-37.15 ng cm-2, respectively. The method is highly sensitive and suitable for 1-15 micrograms ml-1 concentrations with the detection limits being in the range, 0.0651-0.1724 microgram ml-1. The method was successfully applied to the studied drugs in their dosage forms. The results are reproducible within +/- 1% and compare favorably with those obtained by the procedures of the British Pharmacopeia.