Researchers are developing two prototype tests to detect fake anti-malarial tablets in just five seconds. Conventional methods take more than two hours.
The new techniques, developed by Facundo Fernandez of the Georgia Institute of Technology in the United States and colleagues, will be published this summer in the journal ChemMedChem.
They can be used to detect tablets that contain less than the recommended dose of artesunate — believed to be the most effective anti-malarial drug — and the presence of other less effective or harmful active ingredients.
Fernandez's team has improved two existing methods known as 'desorption electrospray ionization' (DESI) developed by Purdue University, and 'direct analysis in real time' (DART) developed by a Japanese company.
Traditional DESI is not sufficiently sensitive to detect artesunate. Fernandez's team added a compound to DESI to stabilise the substance, which made it easier to detect.
In addition, the team is combining DART technology, which accelerates screening, with instruments already used to detect counterfeit drugs.
One such instrument is a mass spectrometer but this is too bulky and expensive to use outside laboratories. The team plans to combine DART with a similar instrument used in airports to detect explosives that will be adapted to screen anti-malarial drugs.
The researchers used the techniques to screen artesunate tablets from Laos, Myanmar and Thailand.
They found tablets containing waste powders left over from the manufacture of other pharmaceuticals, an analgesic suspected of causing serious bone marrow disorders and anti-malarials that are ineffective in South-East Asia.
They also found tablets containing 10 milligrams of artesunate instead of the 50 milligrams present in the genuine product.
Low doses of artesunate are dangerous in the long-term as they could help resistant strains of the malaria parasite emerge.
In another article published today (13 June) by PLoS Medicine, a team of researchers from Asia, Africa and Europe say that up to half of the artesunate pills in South-East Asia could contain no active ingredient at all.
Between 38 and 52 per cent of the tablets they sampled were made of starch, chalk and a variety of unconventional active ingredients.
They say counterfeit drugs have led to an unnecessary loss of life for profit,
a loss of confidence in artesunate, and have given rise to false reports of resistance to the drug.
In 2004, 34 countries in Africa adopted artemisinin-based therapies as their first line of treatment against malaria.
The spread of counterfeits is exacerbated by the high cost and short supply of artemisinin.
ChemMedChem doi:10,1002/cmdc20060041 (2006)
PLoS Medicine 3(6): e197 (2006)