Preparation, characterization, and drug release behaviors of drug-loaded epsilon-caprolactone/L-lactide copolymer nanoparticles

Copolymers of epsilon-caprolactone and L-lactide (PCLLA) with different mon omer ratio were synthesized by ring opening polymerization, and drug-loaded nanoparticles of poly-epsilon-caprolactone (PCL), poly-L-lactide (PLLA), a nd their copolymers were prepared by precipitation method, respectively. Th e results of differential scanning calorimetry and X-ray diffraction indica ted that the copolymerization of PCLLA decreased the crystallinity of the p olymers, and the results of transmission electron micrograph and laser ligh t scattering (LLS) revealed that the prepared nanoparticles had a spherical shape, and the size of PCLLA nanoparticles (similar to 85 nm) was smaller than that of the PCL and PLLA nanoparticles. The experiment of in vitro dru g release showed that the drug release rate from PCLLA nanoparticles was sl ower than that from PCL and PLLA nanoparticles, and the release profile of PCL6/LA4 nanoparticles appeared to follow zero order kinetics. These result s suggested that the polymer composition made a great influence on the nano particle size and drug release behavior. (C) 2000 John Wiley & Sons, Inc.