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

The 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 mechanism was considered to be diffusion of the drugs in the initial period. Following this, with the hydrolysis of PLA to form a colloidal viscous layer, drug release is due to the combined effect of diffusion and erosion of the polymer matrix. Additionally, drug release behavior is closely related to the degradation mechanism of the polymer carrier. The results suggest that AGM could be developed as a potential delivery system for long-acting intramuscular administration with extensive application prospects.

Formulation and Pharmacokinetics of HSA-core and PLGA-shell Nanoparticles for Delivering Gemcitabine.

Gemcitabine-loaded core-shell nanoparticles (CSNPs), comprised of a cross-linked HSA-core and PLGA-shell, were prepared through a modified double emulsification method, and the processing parameters were systematically investigated. The optimized CSNPs had a particle size of 241 ± 36.2 nm and an encapsulation efficiency of 41.52%. The core-shell structure was characterized by optical microscope (OM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The amorphous nature of the encapsulated drug was confirmed by differential scanning calorimetry (DSC) and X-ray diffraction (XRD). An in vitro release study demonstrated that the CSNPs had an improved sustained release profile controlled by erosion of materials in combination with drug diffusion. In vivo pharmacokinetics of CSNPs obtained a bigger area under concentration-time curve (AUC), t 1/2, and C max compared to free drug solution. The results suggest that HSA-PLGA-based CSNPs can be a promising carrier for the sustained release of gemcitabine.