Core-stabilized polymeric micelle as potential drug carrier: Increased solubilization of taxol

Poly(ethylene glycol-b-lactide) possessing a methoxy group at the poly(ethy lene glycol) (PEG) chain end and a polymerizable methacryloyl group at the poly(lactic acid) (PLA) chain end (MeO-PEG/PLA-methacryloyl) was prepared b y an anionic ring-opening polymerization of ethylene oxide and DL-lactide i n tandem manner initiated with a potassium 2-methoxyethanolate,followed by end-capping with an excess of methacrylic anhydride. The molecular weight o f the obtained polymer was controlled by the initial monomer/initiator rati o, which was confirmed by the combination of gel permeation chromatography and nuclear magnetic resonance analyses. The functionality of the methacryl oyl-PLA end was almost quantitative. The MeO-PEG/PLA-methacryloyl (38/35; t hese numbers in parentheses denote the molecular weights of PEG and PLA seg ments divided by 100, respectively) formed a cove-shell type spherical mice lle in aqueous media obtained by a dialysis technique, the cumulant diamete r of which was ca. 30nm with very low polydispersity factor. The methacryloyl group adjacent to the PLA was polymerized in the PLA core of the micelle. The polymerization proceeded thermally with radical initiat or and photochemically with photo-initiator to produce core-polymerized nan oparticles, which was found spectroscopic and light-scattering techniques. incorporated micelles were prepared to entrap Taxol into MeO-PEG/PLA-methac ryloyl block copolymer micelles by the oil/water emulsion method. Copyright (C) 1999 John Wiley & Sons, Ltd.