Determination of chloroquine and its decomposition products in various brands of different dosage forms by liquid chromatography.

Various commercial preparations of chloroquine dosage forms have been examined both by thin-layer chromatography (TLC) and liquid chromatography (LC). TLC showed that all these preparations yielded more than one spot, indicating possible degradation. An LC method has been adapted for the determination of chloroquine in these drug formulations. The standard calibration curve was linear over the concentration range 1-6 micrograms ml-1. Chloroquine was assayed in various brands of different forms (ampoules, tablets and syrups). However, it was observed, for some samples, that the bands obtained were rather broad, showing shoulders or peak splitting, indicating the presence of other compounds coeluting with chloroquine. The utility of this method for the quality control of this major drug is assessed in the context of the need to carefully monitor drug purity in a tropical climate, particularly in situations where there may be doubt about the quality of the primary manufacturer.