Enantioseparation of the antidepressant reboxetine

The enantioseparation of reboxetine by HPLC was investigated using chiral stationary phases (CSPs) containingcellulose Tris(3,5-dimethylphenyl)carbamate on silica gel (Chiralcel OD column) as the chiralselector. Reversed phase HPLC was the technique of choice for the analytical enantioseparation of reboxetine,while the chiral semipreparative separation was obtained with the same CSP, but in normal phaseconditions. The effects of the mobile phase pH and composition on analytical retention, enantioselectivityand resolution were investigated. The best performance was obtained using a mobile phase composed of0.5Msodium perchlorate at pH 6 and acetonitrile in the 60/40 (v/v) ratio. The semipreparative separationhas allowed obtaining pure enantiomers, but required the preparation of reboxetine free base. Differentn-hexane/alcohol mixtures were tested as mobile phases, varying both the nature of the alcohol and itspercentage in the mobile phase. Different n-hexane/alcohol mixtures were tested as mobile phase andthe best results were obtained by using a mobile phase composed of n-hexane and 2-propanol (80:20,v/v).