Resolution of enantiomers of bupropion and its metabolites by liquid chromatography

Bupropion, a tricyclic aminoketone, is used primarily in the treatment of depression, the management of patients with bipolar and schizo-affective disorder, and the treatment of Parkinson's disease. Bupropion is marketed as a racemate, but the racemic mixture is known to have several disadvantages while the two isomers of bupropion and its metabolite differ significantly in their pharmacological activities. Therefore, the stereoselective determination of the drug enantiomers in pharamaceutical dosages, plasma or urine is of potential clinical and analytical importance. Different chromatographic methods have been employed for the separation of the two enantiomers. This is the first attempt to review the methods of enantiosepartion of bupropion using both direct and indirect approaches in both HPLC and TLC. The review presents a detailed discussion on the use of chiral stationary phase (based on polysaccharide, α1 acid glycoprotein and ovomucoid column) and chiral derivatizing reagents (based on isothiocyanate and cyanuric chloride) along with TLC separation of bupropion enantiomers using ligand exchange and impregnation methods. The focus is also on the separation mechanism for enantioresolution using the various methods described herein.