Formulation conditions on the drug loading properties of polymeric micelles

Methyl poly(ethylene glycol) grafted poly (lactide-co-(glycolic acid)-alt-(glutamic acid) amphiphilic copolymers (PLG-g-mPEG) were fabricated polymeric micelles to load anticancer drug doxorubicin (DOX). Both blank and drug loaded micelles were spherical nanoparticles with the mean sizes around 50 and 100nm, respectively. The effects of formulation conditions including compositions, concentrations, temperature, feeding doses and solvents on the size and drug loading content were investigated, the storage of the drug loaded micelles was explored. The results showed that the short graft mPEG chain length was favorable for the loading of DOX. The increase of temperature was preferable for receive micelles with higher drug loading content and smaller size. The encapsulation of polymeric micelles could protect the bioactivity of DOX. In vitro drug release profiles illustrated that the drug release from polymeric micelles with long mPEG chains was much faster than from micelles with short mPEG chains. The release kinetics of drug from micelles fitted to the Ritger-Peppas equation well and the release process followed diffusion mechanism.