Micellization and controlled release properties of methoxy poly(ethylene glycol)-b-poly(D,L-lactide-co-trimethylene carbonate)

Abstract

Amphiphilic block copolymers composed of D,L-lactide, trimethylene carbonate and methoxy poly(ethylene glycol) (PETLA) were synthesized with ring-opening copolymerization. Studies on the micellization and drug-controlled release behavior of PETLA were performed. Both of the copolymers and the micelles were characterized with the methods of ¹H nuclear magnetic resonance (¹H-NMR), fluorescence spectroscopy, gel permeation chromatographic (GPC), dynamic light scattering (DLS), transmission electron microscopy (TEM) and ultraviolet-visible spectroscopy (UV). As a result, the critical micelle concentration of the copolymer was decreased with the increase of the hydrophobic chain length. DLS resulys indicated the diameters of the micelle were increased with increasing of hydrophobic length. TEM photographs illustrated that micelles MT1 were regularly spherical with the diameter from 30 nm to 40 nm. Taking 9-nitro-20(S)-camptothecin (9-NC) for the model drug, the release profiles in vitro show that the release behavior from micelles was controllable and nearly in zero order after the initial burst release.

Keywords

biodegradable / methoxy poly(ethylene glycol)-b-poly(D / L-lactide-co-trimethylene carbonate) / micelle / controlled release

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