Injectable sustained release PLA microparticles prepared by solvent evaporation-media milling technology

AbstractThe objective of this study was to develop agomelatine (AGM) intramuscular sustained release PLA microparticles by using solvent evaporation combined with wet milling technology. The final preparation had a regular and homogeneous particle size of approximately 35 µm, as measured by laser diffraction particle size analysis and scanning electron microscopy (SEM). The drug was confirmed to be within the carrier in an amorphous state through differential scanning calorimetry (DSC) and power X-ray diffraction (PXRD) experiments. Additionally, Fourier transform infrared spectroscopy (FT-IR) analysis was applied to confirm that there was hydrogen bonding between the drug and polymer at the molecular level. In vitro release experiments indicated that the drug could achieve long-term sustained release over the period of one month, with only a 3.07% burst release, due to the involvement of the polymer and removal of drug adsorbed on the surface during the wet grinding process. The dominant release mechanis...