Synthesis and characterization of star-shaped PLLA with sorbitol as core and its microspheres application in controlled drug release

摘要

The purpose of this study was to investigate the suitability of a six-arm star-shaped poly(l-lactide)s (s-PLLA) as controlled drug carriers for hydrophobic drug molecules. First, s-PLLA was synthesized by ring-opening polymerization of l-lactide using sorbitol as initiator and stannous octoate as catalyst. The structure and molecular weight (M-w) of s-PLLA was characterized with H-1 NMR, C-13 NMR, and GPC. Second, rifampicin (RIF) used as a model drug was encapsulated within the microspheres of s-PLLA via oil-in-water emulsion/solvent evaporation technique. The morphology, drug encapsulation efficiency (EE), and in vitro release behavior of the prepared microspheres were studied in details. Results indicated that the average diameters of s-PLLA microspheres can be controlled between 8 and 20 mu m by varying the copolymer's concentration or M-w. The EE of RIF was mainly determined by the concentration of s-PLLA. The in vitro study showed that the burst release behavior can be depressed by increasing the M-w of the s-PLLA. Present work suggests that the synthesized s-PLLA could be used as a new material for drug delivery. (c) 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42213.