Formation of methotrexate-PLLA-PEG-PLLA composite microspheres by microencapsulation through a process of suspension-enhanced dispersion by supercritical CO2.
BACKGROUND
The aim of this study was to improve the drug loading, encapsulation efficiency, and sustained-release properties of supercritical CO(2)-based drug-loaded polymer carriers via a process of suspension-enhanced dispersion by supercritical CO(2) (SpEDS), which is an advanced version of solution-enhanced dispersion by supercritical CO(2) (SEDS).


METHODS
Methotrexate nanoparticles were successfully microencapsulated into poly (L-lactide)-poly(ethylene glycol)-poly(L-lactide) (PLLA-PEG-PLLA) by SpEDS. Methotrexate nanoparticles were first prepared by SEDS, then suspended in PLLA-PEG-PLLA solution, and finally microencapsulated into PLLA-PEG-PLLA via SpEDS, where an "injector" was utilized in the suspension delivery system.


RESULTS
After microencapsulation, the composite methotrexate (MTX)-PLLA-PEG-PLLA microspheres obtained had a mean particle size of 545 nm, drug loading of 13.7%, and an encapsulation efficiency of 39.2%. After an initial burst release, with around 65% of the total methotrexate being released in the first 3 hours, the MTX-PLLA-PEG-PLLA microspheres released methotrexate in a sustained manner, with 85% of the total methotrexate dose released within 23 hours and nearly 100% within 144 hours.


CONCLUSIONS
Compared with a parallel study of the coprecipitation process, microencapsulation using SpEDS offered greater potential to manufacture drug-loaded polymer microspheres for a drug delivery system.
College of Chemical Engineering, Institute of Biomaterials and Tissue Engineering, Huaqiao University, Xiamen 361021, China.
Ai-Zheng
AZ
Chen
Guang-Ya
GY
Wang
Shi-Bin
SB
Wang
Li
L
Li
Yuan-Gang
YG
Liu
Chen
C
Zhao
D002245:Carbon Dioxide / Q000737:chemistry*; D011232:Chemical Precipitation; D007773:Lactates / Q000737:chemistry*; D008727:Methotrexate / Q000737:chemistry* / Q000493:pharmacokinetics; D053769:Nanocapsules / Q000737:chemistry*; D010316:Particle Size; D011092:Polyethylene Glycols / Q000737:chemistry*; D013499:Surface Properties; D013535:Suspensions / Q000737:chemistry
D007773:Lactates; D053769:Nanocapsules; D013535:Suspensions; C088513:poly(lactic acid-ethylene glycol); D002245:Carbon Dioxide; D011092:Polyethylene Glycols; D008727:Methotrexate