There is no analytical monograph in the United States Pharmacopeia (USP) or British Pharmacopoeia (BP) for the assay of chloroquine syrup. A high pressure liquid chromatography (HPLC) method was developed and validated in-house for the determination of chloroquine in chloroquine syrup. Validation of the method was carried out according to the validation criteria of the USP and the guidelines of the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use. Validation parameters, such as specificity, linearity, accuracy and precision, as well as chromatographic parameters, such as peak symmetry and resolution, were assessed and optimized.

As the laboratory did not know the type of excipients used in the various formulations, the method was only validated for interference from the most generally used preservatives such as the parabens (hydroxy benzoates) and benzoic acid. Evidence of interference from any other preservative not validated for could not be detected during the analysis, and therefore the HPLC method was assumed to be specific for the determination of chloroquine in chloroquine syrup.

The method parameters were as follows:

Performance criteria of the method:

Although the method was not specifically validated to indicate all five possible decomposition products due to photo degradation, no peaks suggesting the decomposition of the analyte before or during the analyses were observed.