Click-imprinted furan-modified poly(acrylonitrile-co-divinylbenzene for S-naproxen recognition

Abstract

Naproxen (NX) drug exists in two R- and S-enantiomers, requiring enantioseparation for effective pharmacological effects. Herein, a new S-NX enantioselective poly(acrylonitrile-co-divinylbenzene) (CPAN)-based polymeric sorbent was successfully synthesized and used to separate the NX racemate. First, low crosslinked CPAN was prepared in microparticles via suspension polymerization. Furan-2-ylmethylhydrazine (Fu-Hyd) was then interacted with the abundant nitrile units. The resulting cationic furan-hydrazidine-functionalized polymeric particles (FUH-P) were loaded with the anionic S-NX, which was then imprinted via post-crosslinking upon treatment with bis-maleimidoethane (BME) dienophile crosslinker that interacted with the conjugate diene system of the already inserted furan units via Diels-Alder cycloaddition reaction. Using acidic elution, the S-NX enantiomers were then freed from the polymer particle and left their enantio-selective receptor-like active sites in the structure of the imprinted polymeric particles (S-NX-P). FTIR, 13C NMR, and XRD techniques were utilized for investigating the obtained polymers. Also, the surface morphologies of the sorbent materials were visualized using SEM. The best conditions for enantio-selective uptake showed that 235 mg/g of S-NX could be adsorbed at pH 7. The enantiomeric separation of the NX racemic mixture was effectively achieved with an enantiomeric excess (ee) of 99% for R-NX upon the initial solution run and 93% for S-NX upon the elution step.