Preparation of Monodispersed Molecularly Imprinted Polymers for Abiraterone and Its Derivatives and Evaluation of...

Monodispersed molecularly imprinted polymers (MIPs) for abiraterone (Abi), 5'-chloroabiraterone (5'-ClAbi), 5'-methylabiraterone (5'-MeAbi), and 6'-methylabiraterone (6'-MeAbi) (MIP_Abi, MIP_5'-ClAbi, MIP_5'-MeAbi, and MIP_6'-MeAbi, respectively) were prepared using methacrylic acid (MAA) and ethylene glycol dimethacrylate (EDMA) as a functional monomer and a crosslinker, respectively, by multistep swelling and polymerization. The molar ratio of the template molecule to MAA and EDMA was 2:7:25. The retention and molecular recognition properties of the non-imprinted polymer and MIPs (MIP_Abi, MIP_5'-ClAbi, MIP_5'-MeAbi, and MIP_6'-MeAbi) were evaluated using a mobile phase consisting of sodium phosphate buffer and acetonitrile in reversed-phase liquid chromatography (LC). Abi, 5'-MeAbi, and 6'-MeAbi showed the highest retention on these MIPs in a mobile phase consisting of sodium phosphate buffer and acetonitrile (50:50) at pH 5.7, whereas 5'-ClAbi exhibited the highest retention in a mobile phase consisting of sodium phosphate buffer and acetonitrile (50:50) at pH 3.7. On the other hand, the imprinting factors of the template molecules followed the order MIP_5'-ClAbi < MIP_5'-MeAbi < MIP_6'-MeAbi < MIP_Abi. The DFT calculations suggested two hydrogen‑bonding interactions between the (substituted) pyridines and the hydroxy groups of Abi and its derivatives with MAAs in the gas phase. The interaction energies followed the order MIP_5'-ClAbi < MIP_Abi < MIP_5'-MeAbi < MIP_6'-MeAbi. These results suggested that ionic or hydrogen-bonding interactions and hydrophobic interactions could work for the retention and molecular recognition of Abi and its derivatives on these MIPs in reversed-phase mode.