Researchers tested 13 brands of artesunate-amodiaquine combinations bought from pharmacies in Lagos, Nigeria and found 85 per cent failed to meet US Pharmacopeia (USP) specifications for one of the actives. The results add to concerns about substandard drugs in sub-Saharan Africa.
“Even though there is no case of outright counterfeiting from the results obtained in the study, the potency of the drugs vary considerably”, the authors wrote in the African Journal of Pharmacy and Pharmacology.
Tests showed all bar two of the 13 sampled artemisinin combination therapy (ACT) brands of contained too much or too little of one or both of the active pharmaceutical ingredients (APIs).
More than half of the products failed USP tests for both actives. Using too little API – one sample had less than two-fifths of its labelled amount – was a problem, but equally so was an excess of an active.
The researchers tested a sample with 160 per cent of the labelled amount of artesunate, but 90 per cent of the expected amodiaquine, and several other brands also suffered from too much of an API.
“It is clear that the quality of most brands of artesunate amodiaquine combined therapy in circulation in Lagos metropolis is less than adequate. This result can be extrapolated for other cities in the sub-Saharan Africa”, the authors wrote.
The finding adds to earlier work in showing the problems faced in tackling malaria in sub-Saharan Africa. Regulators and governments are working to boost local manufacturing and quality but the authors stress there is much work to do.
“It is a herculean task to monitor every single batch of every single brand in these poor countries due to lack of quality control infrastructures and limited expertise and manpower in the relevant agencies in these countries”, the authors wrote.