EXTRACTIVE VISIBLE SPECTROPHOTOMETRIC DETERMINATION OF CHLOROQUINE IN PHARMACEUTICAL AND BIOLOGICAL MATERIALS

Extractive visible spectrophotometric method is described for the analysis of chloroquine in it pure forms, pharmaceutical dosage forms and biological materials. Linearity, precision, stability and accuracy were evaluated according to the recommended validation procedure. In the described method a drug complex was formed with cobalt thiocyanate reagent, buffered and extracted into nitrobenzene and absorbance determined at 625nm wavelength. Good linearity was obtained between 2µg/ml and 60µg/ml. The coefficient of variation of 5 determinations of a single sample of 2µg/ml was 1.2% and that of 0.02µg/ml was 20.3%. The mean coefficient of variation over the whole range of standard samples was 10.5+3.3% (s.d.). An assay of acceptable accuracy can be accepted down to a concentration of 0.02µg/ml. The intra- day and inter- day precision values were less than 2% for all samples analysed. The accuracy, as seen in or estimated from the percent recovery studies, was between 96 and 99% with an average of 97.75% in biological materials, common excipients and sampled tablets. Non- aqueous titration was employed as a parallel validation procedure of the described method. The volumetric determination gave good results in itself and showed good agreement with similar determination using the described method. The described method was applied to pharmaceutical formulation (chloroquine tablets) and biological materials. Statistical analysis of variance showed no significant difference between results obtained by the described method.