| Abstract: | In this study, peptide-loaded microparticles were prepared using an aerosol solvent extraction system (ASES) by employing
supercritical carbon dioxide as an antisolvent. The effects of the molecular weight of poly(Llactide) (PLLA), poly(ethylene
glycol) (PEG), the block length of methoxy poly(ethylene glycol)-b-poly(L-lactide) (mPEG-PLLA), the blending of PLLA and PEG, and the drug-to-polymer feed ratio on the formation of leuprolide
acetate (LA)-loaded microparticles and their release characteristics were investigated. Scanning electron microscope observations
showed that the LA-loaded polymer particles had a spherical morphology with a smooth surface. The entrapment efficiency of
LA in the ASES-processed microparticles was found to be extremely high (about 99%), whereas the initial release rate of the
LA-loaded microparticles was very low for PLLA. The release rate of LA was observed to increase as the PEG block length of
mPEG-PLLA and/or the drug content in the microparticles increased. When PLLA was blended with PEG, the release rate of LA
from the PLLA/PEG microparticles was significantly faster compared with the corresponding mPEG-PLLA copolymer. |
