Optically Active Microspheres Containing Schiff Base: Preparation and Enantio-Differentiating Release toward Drug Citronellal

This article reports an innovative type of drug-loaded microspheres prepared by precipitation polymerization. The microspheres consist of optically active helical substituted polyacetylene main chains and Schiff base side groups, in which the former provides helical chirality while the latter is used for chiral citronellal loading. Scanning electron microscopic images showed that microspheres with average size of about 1 μm were synthesized. Circular dichroism and UV–vis absorption spectra demonstrated that the polymer chains existed in predominantly one-handed helical structures which contributed largely to the optical activity of the microspheres. The helical structure of polymer and the Schiff base endowed the microspheres with pH- and time-dependent properties and enantio-differentiating resolution capacity toward citronellal. The novel optically active microspheres have potential applications in the fields of chiral drug separation and release, biomedicine, etc.