Self-assembled filomicelles prepared from polylactide/poly(ethylene glycol) block copolymers for anticancer drug delivery.

Bioresorbable filomicelles present many advantageous as drug delivery systems e.g., long circulation time and high loading efficiency. The aim of this study was to develop polylactide/poly(ethylene glycol) (PLA/PEG) filomicelles for drug delivery applications. A series of PLA/PEG diblock copolymers were synthesized using non-toxic initiator, and characterized by means of NMR and GPC. Analysis of morphology of micelles determined by TEM revealed that apart from the weight fraction also the molar mass of PEG and the stereochemistry of PLA block must be considered for tailoring micellar structures. The CMC was found to be dependent on the length and structure of the hydrophobic block. It was observed that the drug loading properties could be improved by selection of appropriate copolymer and encapsulation method. Slower release of paclitaxel was observed for mPEG5000 initiated copolymers than mPEG2000 initiated copolymers. Moreover, the influence of the length of hydrophobic block and its stereoisomeric form on drug release rate was evidenced. Therefore, PLA/PEG filomicelles with good stability, high drug loading capacity and sustained drug release appear most attractive for drug delivery applications.