| Research Abstract |
A uniform-sized molecularly imprinted polymer (MIP) for (S)-propranolol and (S)-naproxen selectively modified with hydrophilic external layer has been prepared. First, the MIPs for (S)-propranolol and (S)-naproxen were prepared using methacrylic acid and 4-vinylpyridine, respectively, as a functional monomer and ethylene glycol dimethacrylate as a cross-linker by a multi-step swelling and thermal polymerization method. Next, a 1 : 1 mixture of glycerol monomethacrylate and glycerol dimethacrylate was used for hydrophilic surface modification, and it was added directly to the MIPs for (S)-propranolol and (S)-naproxen 4 h after the start of molecular imprinting. The retention factors of all solutes tested were decreased with the surface modified MIP, compared with the unmodified MIP. However, chiral recognition of racemic propranolol or naproxen was attained with the surface modified MIP as well as the unmodified MIP. Further, bovine serum albumin was completely recovered from the surface modified MIP. These results revealed that the chiral recognition sites of (S)-propranolol or (S)-naproxen remained unchanged with hydrophilic surface modification, and that the MIP for (S)-propranolol or (S)-naproxen was selectively modified with hydrophilic external layer. The results reveal that the surface modified MIP could be applicable to direct serum injection assays of (S)-propranolol or (S)-naproxen. However, the use of the (S)-propranolol- or (S)-naproxen-imprinted polymers for the selective trapping at a low concentration of the drug resulted in a serious problem because of elution of (S)-propranolol or (S)-naproxen, which remained within the MIP after preparation. We prepared a MIP using a structurally related compound, (S)-pindolol or ibuprofen, as the template. Now, simultaneous determination of (S)-propranolol or (S)-naproxen and its metabolites in biological fluids using the MIP is in progress.
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