Fast chiral separation of drugs using columns packed with sub-2 microm particles and ultra-high pressure

The use of columns packed with sub-2 microm particles in liquid chromatography with very high pressure conditions (known as UHPLC) was investigated for the fast enantioseparation of drugs. Two different procedures were evaluated and compared using amphetamine derivatives and beta-blockers as model compounds. In one case, cyclodextrins (CD) were directly added to the mobile phase and chiral separations were carried out in less than 5 min. However, this strategy suffered from several drawbacks linked to column lifetime and low chromatographic efficiencies. In the other case, the analysis of enantiomers was carried out after a derivatization procedure using two different reagents, 2,3,4-tri-O-acetyl-alpha-D-arabinopyranosyl isothiocyanate (AITC) and N-alpha-(2,4-dinitro-5-fluorophenyl)-L-alaninamide (Marfey's reagent). Separation of several amphetamine derivatives contained within the same sample was achieved in 2-5 min with high efficiency and selectivity. The proposed approach was also successfully applied to the enantiomeric purity determination of (+)-(S)-amphetamine and (+)-(S)-methamphetamine. Similar results were obtained with beta-blockers, and the separation of 10 enantiomers was carried out in less than 3 min, whereas the individual separation of several beta-blocker enantiomers was performed in 1 min or less.