Synthesis of Folate-conjugated Stearic Acid Grafted Bletilla striata Polysaccharides Copolymers and Application for Delivering Antitumor Drugs as a Drug Delivery Carrier

Folate-conjugated stearic acid-grafted Bletilla striata polysaccharides copolymers (FA-BSPs-SA) were prepared and characterized using H-1 nuclear magnetic resonance spectroscopy (H-1 NMR), ultraviolet visible spectrophotometry (UV) and infrared spectroscopy (IR). Docetaxel-loaded FA-BSPs-SA (DTX-loaded FA-BSPs-SA) micelles were prepared by an emulsion-solvent evaporation method and characterized. The cytotoxicity of copolymers and DTX-loaded micelles was evaluated by MTT assay. The results of H-1 NMR and IR demonstrated that stearic acid and folic acid have been grafted on Bletilla striata polysaccharide. Docetaxel could be entrapped into micelles of FA-BSPs-SA copolymer. DTX-loaded BSPs-SA copolymer micelles displayed pH-dependent properties in the respects of in vitro release behavior ranging from pH = 5. 0 to pH = 7. 4. The particle sizes of DTX-loaded micelles decreased whereas encapsulation efficiency and loading capacity increased with the substitution degree increase of folic acid. The cell survival rates subjected to FA-BSPs-SA and BSPs-SA were still above 80% at the concentration of 40 mu g/mL. The anti-tumor effect in vitro of DTX-loaded FA-BSPs-SA and DTX-loaded BSPs-SA micelles were superior to that of DTX solution at the same concentration. More-over, DTX-loaded FA-BSPs-SA micelles exhibited stronger inhibitory effects on tumor cells with foate receptor expression in comparison to DTX-loaded BSPs-SA micelles. FA-BSPs-SA polymers are expected to be nanoscale materials for hydrophobic antitumor drugs.