Click chemistry-driven post-imprinting of carboxylated polymer for Selective recognition of S-rivastigmine

Here, in the present article, a novel molecularly imprinted polymer (MIP), S-RV-P, was prepared for the recognition and separation of the S-enantiomer of rivastigmine (S-RV) from its racemic form. Synthesis involved the formation of a poly(styrene-co-maleic anhydride) (PSM) matrix that was functionalized with 2-aminoethane-1-thiol (ATH) to introduce thiol and carboxylic acid functionalities to prepare the precursor HS-P-COOH. Post-imprinting was achieved through thiol-maleimide click crosslinking via bismaleimide (BMA) facilitated by S-RV to generate the resultant S-RV-P polymer. The kinetic analysis presented second-order kinetics, while the spontaneity and optimal crosslinking at 60 °C were confirmed by thermodynamic analysis. Thermal analysis presented improved structural stability of the crosslinked polymer. Adsorption experiments demonstrated that S-RV-P had about two times greater affinity for S-RV compared to NIP, optimal pH 6-7 for adsorption, and maximum capacity 326 mg/g. Isotherm fitting was best described by the Langmuir isotherm for monolayer adsorption. Selectivity evaluation demonstrated remarkable enantioselectivity of S-RV-P for S-RV. Gravity column separation also demonstrated high-resolution chiral discrimination with 91% ee for R-RV and 97% ee for S-RV. These findings point to the success of the imprinting process and S-RV-P's potential in drug enantio‑purification.