Washington : A group of 22 researchers from Colorado State University in the US Scientists have developed a paper-based test for antibiotics that turns a distinctive red colour on detecting fake or substandard drugs within minutes.
The World Health Organization (WHO) estimates that up to 10 per cent of all drugs worldwide could be falsified, with up to 50 per cent of those some form of antibiotics.
For the test, the user dissolves the antibiotic in water, and adds the solution to a small paper device.
The paper contains a molecule called nitrocefin that changes colour when it reacts with the enzyme. In this setup, the antibiotic and the nitrocefin on the paper are in competition to bind with the enzyme in a detection zone.
With a good antibiotic dose, there is little colour change in the paper strip, because the antibiotic outcompetes the nitrocefin and successfully binds with the beta-lactamase enzyme.
However, in a falsified or weakened antibiotic, the paper goes red, because the enzyme instead reacts with the nitrocefin.
In short, yellow means good (appropriate strength antibiotic) and red means bad (diluted antibiotic).
The research, which was led by Prof. Chuck Henry, is described in a paper that was recently published in the journal ACS Sensors.