The study, published in Scientific Reports, is a collaboration between the Medicine Quality Research Group, Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, and MORU Bangkok, working with stable isotope scientists at IsoForensics Inc.
The isotopic composition of materials can yield clues to their origin: oxygen isotopes can provide geolocation information related to global variations in environmental water, while carbon isotope compositions can be linked to differences in photosynthetic pathways of plants. Such clues have previously been used by researchers to estimate the African origins of ivory seized in Asia.
Led by Professor Paul Newton, Professor of Tropical Medicine at MORU and Head of the Medicine Quality Research Group at IDDO, the research team used the same techniques and found that the starch stable isotope signatures differed between the falsified and the genuine samples. Maize starch is a common component in many medications, including in falsified antimalarials. Therefore, they also compared the signatures of maize starch of known geographical origin, to produce a comparison dataset. The analysis supports that the pattern of oxygen stable isotopes (that vary geographically by rainfall) could predict where the maize was actually grown.
Prof Newton said: ‘These findings suggest that this kind of isotope ratio mass spectrometry may be a useful tool for profiling falsified antimalarials and for estimating where the maize yielding the starch excipients were grown.’ These findings are being further investigated as part of the FORESFA project.
The Medicine Quality group’s ongoing Forensic Epidemiology and impact of Substandard and Falsified Antimicrobials project is a collaborative project which adapts and evaluates forensic tools to identify sources and trade routes of substandard and falsified antimicrobials.
Read the full paper here: link.springer.com/article/10.1038/s41598-024-54168-9