Chiral Particles Consisting of Helical Polylactide and Helical Substituted Polyacetylene: Preparation and Synergistic Effects in Enantio-Differentiating Release

The present work reports on the synthesis of chiral particles consisting of helical polylactide (PLA) and helical substituted polyacetylene, aiming to investigate the chiral synergetic effects of the two helical components in enantioselectivity. For this purpose, polylactide with polymerizable terminal alkynyl group was prepared and subsequently used as macromer to copolymerize with chiral alkynyl monomer to form the target particles. SEM images demonstrate that the particles possessed porous structures. Circular dichroism shows that the helical substituted polyacetylene had an influence on the helical screw sense of polylactide chains, thereby affecting the enantioselectivity of the chiral particles in releasing the model chiral drug naproxen. Compared with our earlier study on enantioselectivity of PLA, copolymerizing PLA with chiral alkynyl monomer improves PLA's enantioselectively discriminating ability in naproxen release and even can reverse the particles' preferential enantioselectivity in releasing naproxen enantiomers.