Chromatographic resolution of the enantiomers of phenylpropanolamine by using molecularly imprinted polymer as the stationary phase

In this study molecular imprinting technology was employed to prepare a spe cific affinity sorbent for the resolution of phenylpropanolamine, a chiral drug. The molecularly imprinted polymer (MIP) was prepared by non-covalent molecular imprinting with either (-)- or (+)-phenylpropanolamine as the tem plate. Methacrylic acid and ethylene glycol dimethacrylate were copolymeriz ed in the presence of the template molecule. The bulk polymerization was ca rried out in chloroform with 2,2'-azobisisobutyronitrile as the initiator, at 4 degreesC and under UV radiation. The resulting MIP was ground into pow ders, which were slurry packed into analytical columns. After removal of te mplate molecules, the MIP-packed columns were found to be effective for the resolution of ()-phenylpropanolamine racemates. The separation factor for the enantiomers ran-ed between 1.8 and 3.8 when the column was packed with MIP prepared with (+)-phenylpropanolamine as the template. A separation fac tor ranging from 2.1 to 3.6 could be achieved from the column packed with M IP, prepared with (-)-phenylpropanolamine as the template. Although the sep aration factor was higher with that previously obtained from reversed-phase column chromatography following derivatization with a chiral agent, elutio n peaks were broader due to the heterogeneity of binding sites on MIP parti cles and the possible non-specific interaction. (C) 2001 Elsevier Science B .V. All rights reserved.