Preparation, properties, and mathematical modeling of microparticles drug delivery systems based on biodegradable amphiphilic copolymers

摘要

A series of biodegradable amphiphilic A-B-A type triblock copolymers P(BLA-PEG-BLA), composed of hydrophilic poly(ethylene glycol) (PEG) as a middle block component (13) and hydrophobic poly(beta-benzyl-L-aspartate) as outer polypeptide block components (A), were synthesized by copolymerization of beta-benzyl-L-aspartate N-carboxy anhydride (BLA-NCA) and the diaminated PEG with the primary amino groups capped at both ends. These P(BLA-PEG-BLA) copolymers were characterized by H-1-NMR, DSC, and GPC. The triblock copolymers were used to prepare three kinds of drug delivery systems including Norfloxacin (INN)-incorporated P(BLA-PEG-BLA) microparticles and tablets. The morphologies of the microparticles were characterized by SEM. The in vitro release properties of the microparticles and tablets in PBS were also evaluated. A mathematical model, which incorporates a linear first-order dissolution term and the transient Fickian diffusion equation, was developed to account for the kinetics of drug release from the INN-incorporated P(BLA-PEG-BLA) microparticles. The results indicated that the overall release process was well controlled by both drug dissolution and diffusion. (C) 2004 Wiley Periodicals, Inc.