Fluorescent microspheres of poly(ethylene glycol)-poly(lactic acid)-fluorescein copolymers synthesized by Ugi four-component condensation

摘要

Microparticles formed by poly(lactic acid) (PLA) and poly(ethylene glycol) (PEG) diblock copolymers containing fluorescein grafted to the polymer chain were synthesized by a Ugi four-component condensation (UFCC) reaction. To synthesize these copolymers, lactide was first polymerized by a ring-opening polymerization with alcohol initiators containing functional groups to give carboxyl-and aldehyde-end-functionalized PLA. Two different fluorescent block copolymers (FCPs) of PEG-PLA conjugated to fluorescein (FCP 1 and FCP 2) were then synthesized by UFCC; they gave yields in the range 65-75%. These copolymers were characterized well according their chemical structures and thermal properties, and we prepared fluorescent microspheres (FMSs) from them with the single emulsion-solvent evaporation method (FMS 1 and FMS 2). A new application of UFCC in the preparation of biomasked drug-delivery systems is proposed. (C) 2015 Wiley Periodicals, Inc.