Chiral molecules cannot be superimposed on their mirror image and such stereoisomeric pairs are referred to as enantiomers. To date, most research on chiral compounds has been based on the incorrect assumption that enantiomers have identical environmental behaviour. The chance of under- or overestimation of toxicity during environmental risk assessment is therefore high as enantiomers differ in their biological properties. Environmental sample matrices are also highly complex and diverse in nature. To resolve these issues, scientists of the CVME (Chiral veterinary medicines in the environment) project investigated the enantioselective toxicity of chiral pharmaceuticals of environmental relevance. The researchers developed and validated three multi-residue analytical methods based on sample microextraction techniques and liquid chromatography-mass spectrometry to quantify chiral drugs and their metabolites. The drugs included analytes such as amoxicillin, ampicillin, carprofen and methylprednisolone that are used for veterinary and human treatment. Furthermore, researchers developed three more multi-residue analytical methods that show great promise for applications involving environmental chiral analysis. Researchers included environmental samples from influents, effluent wastewater and activated sludge for their exhaustive study on the environmental impact and persistence of selected chiral drugs. In addition, they also collected samples over a six-month period to get an overview of the environmental fate of chiral drugs and identify the pollution hotspots. Study outcomes sound an alarm as they revealed that several targeted chiral drugs are widespread in the environment with varying levels of ecotoxicity. These findings underscore the need for further studies to fully elucidate the environmental impact of chiral drugs and develop better regulatory standards for accurate environmental risk assessment.
Chiral medicines, toxicity, enantiomer, CVME, multi-residue analytical methods