Synthesis, characterisation and in vitro release of paclitaxel-loaded polymeric micelles

A novel folic acid (FA) poly (ethylene oxide) (PEO)/poly (lactic acid) (PLA) block copolymer conjugate (FA-PEO-PLA) was successfully synthesised by a two-step reaction. FA-PEO-PLA can form mixed micelles with low critical micelle concentration (3.2 x 10(-3) wt%). The physical properties and the structure of micelles were characterised by size distribution and transmission electron microscopy. The micelles exhibited uniform spherical structure and the average diameter was 107.9 nm with narrow size distribution (polydispersity index 0.214). Paclitaxel was loaded in micelles and the encapsulation efficiency of paclitaxel was 43%. The in vitro release of paclitaxel from micelles was initially fast in the first 8 h followed by sustained release. The Weibull model was the most appropriate mechanism for describing the release procedure. These results indicated that the FA-PEO-PLA can be used as a carrier for hydrophobic anticancer drugs.