Addition of N-carbobenzyloxy-l-tryptophan as a co-template molecule to molecularly imprinted polymer monoliths for (+)-nilvadipine

Molecularly imprinted polymer (MIP) monoliths for (+)-nilvadipine have been prepared using 4-vinylpyridine as a functional monomer and toluene/1-dodecanol as a porogen without or with addition of N-carbobenzyloxy-l-tryptophan (Cbz-l-Trp) as a co-template molecule. The MIP monoliths prepared with (+)-nilvadipine as a sole template molecule had no macro through-pores, while those could be formed by addition of Cbz-l-Trp as the co-template molecule. Furthermore, on the former nilvadipine enantiomers could not be separated, but on the latter they could. The presence of Cbz-l-Trp affected the polymerization process and resulted in forming macro through-pores of the MIP monoliths for (+)-nilvadipine and attaining separation of nilvadipine enantiomers. These results suggest that co-addition of Cbz-l-Trp could be effective for preparing MIP monoliths for (+)-nilvadipine, whose preparation is difficult.