Chiral separation of cathinone derivatives used as recreational drugs by cyclodextrin-modified capillary electrophoresis

In recent years, cathinone derivatives have entered the global drug market and caused serious social problems in many European countries. Modification of the basic structure of cathinone leads to a multitude of derivatives, including the most popular representative mephedrone. All those substances contain a stereogenic center and therefore two isoforms exist. As it is the case with many chiral active pharmaceutical ingredients, even the pharmacological effect of the enantiomers of those psychoactive compounds may differ. During this research, an easy-to-prepare chiral capillary zone electrophoresis method for the enantioseparation of a set of 19 cathinone derivatives was developed. Testing different types of cyclodextrin (CD), including native-β-CD, carboxymethyl-β-CD, 2-hydroxypropyl-β-CD, sulfated-β-CD, and native γ-CD, best results were obtained with the negatively charged sulfated-β-CD. The effect of the CD concentration, the temperature, and the addition of ACN to the BGE on the enantioseparation is shown by three model compounds. Under optimal conditions, using 20 mg/mL sulfated-β-CD in 50 mM ammonium acetate buffer pH?= 4.5 containing 10% v/v ACN at a cassette temperature of 40°C and with an applied voltage of 20 kV, all derivatives except methedrone were resolved in their enantiomers within 20 min.