Synthesis and characterization of end-capped biodegradable oligo/poly(trimethylene carbonate)s

Abstract

A series of cholesteryl end-capped biodegradable oligo/poly(trimethylene carbonate)s were synthesized and characterized. The end-capped oligomers/polymers were synthesized by the ring-opening polymerization of trimethylene carbonate (TMC) initiated by cholesterol bearing a hydroxyl group without adding any catalyst. The end-capped oligomers/polymers with different molecular weights were obtained by controlling the feed ratio of the initiator cholesterol to the monomer TMC. The cholesteryl end-capped oligomers/polymers were characterized by Fourier transform-infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy (NMR), gel-permeation chromatography (GPC), differential scanning calorimetry (DSC) and polarizing light microscopy (PLM). Incorporation of cholesteryl moieties results in liquid crystallinity of the end-capped oligomers/polymers when their molecular weights are not very high. Using the MTT assay, the end-capped biodegradable oligo/poly(trimethylene carbonate) is proved to have a low cytotoxicity. The microsphere drug-delivery system of an end-capped polymer was fabricated and its drug-release properties were evaluated.