Marie Choules, a PhD student at the Institute for Tuberculosis Research, has recently published her first research article highlighting the relevance of purity determination and identification of minor impurities in drug discovery.
The case presented in her article demonstrates that impurities (in her case an analogue of the antibiotic rufomycin) even present in trace amounts (< 1% w/w) can be responsible for the measured biological activities.
If impurities are overlooked during drug discovery, the measured biological activities can be wrongly attributed to the major, most abundant compound (in her case rufomyazine).
Beware of minor impurities, they can have major impacts in your bioassays! A really interesting read indeed…