Enantioselective analysis of chiral pharmaceuticals in environment Edmond Sanganyado and Jay Gan Department of Environmental Science University of California Riverside

2 Chiral center Thalidomide Tragedy

Chiral Pharmaceuticals in the Environment U.S. Geological Survey, 3

Purpose of Study Develop method for enantioseparation of chiral pharmaceuticals Determine the enantiomeric composition of chiral pharmaceuticals in the environment 4

Enantioseparation achieved in normal phase HPLC Rs 1.10 Rs 1.66 Rs

Enantioseparation on Vancomycin based column 6 A: 80 % 20 mM ammonium acetate B: 20 % organic modifier

Enantioseparation on Vancomycin based column Effect of amount and type of inorganic salts van’t Hoff plots Mechanism of chiral recognition 7 Mobile Phase: Methanol + 0.1% acetic acid + 0.1% triethylamine 1.0ml/min flow rate

Effect of type and amount of ammonium salt on Rs and α 8

Effect of pH on enantioseparation 9

Effect of temperature on Rs and α in PIM 10

Temperature dependence of retention and selectivity factors 11 Mobile phaseAtenololFluoxetine Additive Conc., mM -ΔH˚ i kJ/mol ΔS i * J/mol r2ir2i -ΔΔH˚ kJ/mol -ΔΔSr2r2 -ΔH˚ i kJ/mo l ΔS i * J/mol r2ir2i -ΔΔH˚-ΔΔSr2r2 Ammonium acetate Ammonium nitrate

Factors affecting separation of enantiomers: Summary 12

Multiresidue separation and extraction in water 1mg/ml racemic standard spiked in 500 ml water Extraction by SPE using HLB cartridge 13

Work in Progress 14

Conclusion Analysis of drugs at trace levels in environmental matrices poses a significant analytical challenge. Development of methods for the enantioseparation of chiral drugs is vital in the understanding of their occurrence, fate and toxicity in the environment. Chiral separation is important for preparing enantiopure compounds required in biodegradation and toxicity experiments. 15

Acknowledgements 16