In situ polymerization preparation of chiral molecular imprinting polymers monolithic column for amlodipine and its recognition properties study

Amlodipine is a first-line therapeutic drug for hypertension and angina pectoris and its vasodilating effect only resides in the S-(-)-enantiomer. But mostly commercial chiral separating matrixes are not capable of enantio-separating of racemic amlodipine. The amlodipine’s the chiral molecular imprinting polymers monolithic column (CMIPMC) was firstly and successfully synthesized by in situ molecular imprinting technique, utilizing S-(-)-amlodipine as the template molecule, methacrylic acid (MAA) as a monomer, and the resulting monolithic colunm could be directly integrated into the high performance liquid chromatography (HPLC) systems. The scanning electron microscope (SEM) was employed to identify the micro-morphologic features of the obtained polymers. Further, the molecule-special recognition mechanism and special selective absorbent properties for the corresponding template were studied by chromatographic system and Scatchard analysis model, respectively. Meanwhile, the optimized chromatographic conditions for chiral separation of amlodipine enantimoers were established. The results showed the obtained CMIPMC had a high specific affinity and selectivity for the template molecule S-(-)-amlodipine, in which chiral separation of racemic amlodipine was achieved under optimized conditions. The mechanism investigation results showed that two kinds of binding sites prevail in the CMIPMC, besides the molecular shape complementation of template molecular and CMIPMC, hydrogen bond or ionic interaction seem to play an important role in the enantio-selective recognition of the CMIPMC. The research laid fundament for the study of expanding the amlodipine chiral separating medium.