Novel cholic acid functionalized star oligo/poly(DL-lactide)s for biomedical applications.

Novel cholic acid functionalized star oligo/poly(DL-lactide)s with different molecular weights were synthesized through the ring-opening polymerization of DL-lactide initiated by cholic acid. Compared with poly(DL-lactide), these star oligo/poly(DL-lactide)s show faster hydrolytic degradation rates, and the degradation mechanism changes from bulk erosion to surface erosion with decreasing molecular weight. Based on the specific physicochemical properties of the novel star oligo/poly(DL-lactide), the drug delivery system with submicron size was fabricated using a very convenient "ultrasonic dispersion method" which did not involve toxic organic solvents. The in vitro drug release was studied.