Rapid and efficient enantioseparation of (S)-amlodipine by surface-imprinted core-shell polymer microspheres

We present a protocol for the preparation of surface-imprinted polymer microspheres by core-shell precipitation polymerization for the enantioseparation of (S)-amlodipine. In this work, submicron mesoporous silica microspheres were prepared with gemini cationic surfactant as soft template. Molecularly imprinted polymers were coated on the silica supports with a low level of crosslinking, and the thickness of the thin-walled imprinted shell was about 45 nm. The material showed fast binding kinetics for (S)-amlodipine (within only 20 min for complete equilibrium), and the saturation adsorption capacity reached 309.2 mg/g, indicating the good accessibility of binding sites and improved mass transfer for target molecule. The imprinted microspheres exhibited an appreciable enantiomeric excess of (S)-amlodipine of 11.3% when used as a glass chromatography column for the enantioseparation of (S)-amlodipine from amlodipine besylate without extra chiral additives. The surface-imprinted materials display potentially amplification for industrial enantioseparation of (S)-amlodipine.