Synthesis, Micellization and Characterization of Novel Amphiphilic β-Cyclodextrin/Poly(L-aspartate) Copolymer

A novel amphiphilic beta-cyclodextrin/poly(L-aspartate)(beta-CD-PASP) copolymer was prepared by ringopening polymerization of polysuccinimide(PSI). This copolymer bears beta-CD units along the macromolecular chain and the structure was characterized by infrared(IR) and proton nuclear magnetic resonance(H-1 NMR). The molecular weight of the copolymer was determined by gel permeation chromatography(GPC). The copolymer micelle were prepared by direct dissolution method. The critical micelle concentration(CMC) of the copolymer micelle was measured by flourescence technique with pyrene as probe. The size distribution of micelle was characterized on a dynamic laser light scattering particle size analyzer and its shape was observed by transmission electron microscopy(TEM). The results show that the copolymer could self-assemble into micelle with a low CMC, and the effective diameter of the micelle was 116.3 nm. The methotrexate(MTX)-loaded micelle were prepared and the drug loading content(DLC) was 22.86%. The MTX-loaded copolymer exhibited a better water-solubility than the free drug.