Chloroquine in the Ugandan market fails quality test: a pharmacovigilance study.

BACKGROUND Antimalaria treatment failure has been partly attributed to poor quality antimalarials in the drug market. A 1998 survey in Kampala showed that 55% of tablets and 62% of injection forms of chloroquine failed the quality test. OBJECTIVE This study was carried out as a follow-up to establish the quality of chloroquine tablet and injection dosage forms in the Ugandan drug market from June - November 2001. METHODS Chloroquine tablets and injection dosage forms, randomly purchased from pharmacies and drug shops in the four regions of Uganda, were assayed for content of the active ingredient according to the USP standard, using the HPLC method. RESULTS Of the tablets samples surveyed, 39% failed the content test with 11% having sub-normal and 28% having supra-normal amounts, whilst 51% of the injection samples failed with 40% and 11% having sub-normal and supra-normal amounts respectively. CONCLUSION There was overall improvement in the quality of chloroquine in Uganda compared with the 1998 figures, but the failure rates are still unacceptably high. The variations in the chloroquine amounts in both the tablet and injection forms may contribute to chloroquine toxicity or poor response during treatment. More vigorous pharmacovigilance on drugs entering the Ugandan drug market is needed.