One Health prescribing - development of enantioselective liquid chromatography - tandem mass spectrometry methods to inform chiral switch of prescription pharmaceuticals.
Wagstaff Tony A TA, Barron Gemma A GA, Pfleger Sharon S, Petrie Bruce B
The One Health philosophy highlights the need to sustainably balance and optimise the health of humans, animals, and ecosystems. Pharmaceuticals are essential for human health, but their usage poses downstream risks to aquatic life. Thus, pharmaceuticals need to be environmentally friendlier whilst delivering the same intended health outcomes. Chiral switch, whereby racemic formulations are replaced with enantiopure versions, is proposed to reduce the environmental burden of pharmaceuticals under the One Health philosophy. This research aimed to develop enantioselective methodologies applicable to complex environmental matrices to inform the chiral switch of commonly prescribed pharmaceuticals. This was achieved using cation exchange solid-phase extraction (SPE) and two separate chiral-high performance liquid chromatography (HPLC) methods for selective detection and quantification of 16 pharmaceuticals (anti-depressants, beta-blockers, calcium-channel blocker, central nervous system stimulant, skeletal muscle relaxant) and primary metabolites in wastewaters. An InfinityLab Poroshell 120 Chiral-V was used to separate cationic enantiomers and CHIRALPAK® ZWIX(+) for zwitterions with enantioresolutions ranging from 0.6 to 4.2. Quantitation limits and trueness values of the SPE-chiral HPLC methods ranged from 6.5 × 10-2 ng L-1 to 42 ng L-1 and from 60% to 119%, respectively. Application of the methodology to wastewater samples revealed several analytes were in non-racemic composition including citalopram, fluoxetine, mirtazapine, desmethylmirtazapine, and ritalinic acid. Greatest enantiomer enrichment was observed for desmethylmirtazapine with a maximum enantiomeric fraction of 0.80. Furthermore, to the best of our knowledge this is the first study to report the enantiomeric composition of baclofen, amlodipine, hydroxyatenolol and ritalinic acid in wastewater. Further application of these newly developed methods can help develop more accurate environmental risk assessments of pharmaceutical enantiomers to inform the proposed chiral switch decision making process in healthcare.