DIRECT HPLC SEPARATION OF THALIDOMIDE ENANTIOMERS USING CELLULOSE TRIS-4-METHYLPHENYL BENZOATE CHIRAL STATIONARY PHASE

A newly developed and commercially available cellulose tris-4-methylphenyl benzoate (Chiralcel OJ) chiral stationary phase was used for the enantiomeric resolution of thalidomide enantiomers. A simple isocratic and direct liquid chromatographic resolution of racemic thalidomide was accomplished without any derivatization. Solvent system was hexane and ethanol (50:50) with the flow rate 1 ml/min. at 23-degrees-C. The capacity factor (k') for the first eluted enantiomer R-(+)-thalidomide was 9.67 and separation factor (alpha) obtained was 1.54. The maximum stereochemical resolution factor (R) obtained was 15.05. Since a large stereochemical resolution with baseline separation was achieved, this method could be used for a large scale preparative separation and also for optical purity determination of the drug in bulk and formulation dosage forms.