Preparation and anti-tumor effect in vitro of doxorubicin-loaded targeting micelles modified by folic acid / 中国药学杂志

ABSTRACT

OBJECTIVE: To prepare doxorubicin (DOX)-loaded micelles based on folic acid-modified cholesterol-glycol chitosan (FCHGC), and study its physicochemical properties and cytotoxicity in vitro. METHODS: FCHGC copolymer was synthesized by conjugating carboxyl groups of folic acid with the primary amino groups of cholesterol-modified glycol chitosan (CHGC) in the presence of coupling agent. FCHGC conjugate was characterized by 1H-NMR and fluorescence measurement using pyrene as a probe. The DOX-loaded micelles were prepared by an emulsion/solvent evaporation method. The size and shape of the micelles were analyzed by dynamic light scattering (DLS) and transmission electron microscopy (TEM). DOX release behavior was studied in vitro by a dialysis method in phosphate buffer saline (PBS, pH 7.4). The cytotoxicity and celluar uptake of drug-loaded micelles in vitro were investigated by 3-(4, 5-dimethyl thiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay and flow cytometry. RESULTS: The critical aggregation concentration (CAC) of the FCHGC micelles in aqueous solution was 0.0163 mg·mL-1. Its particle size was 227 nm. The drug loading and encapsulation efficiency of DOX-loaded FCHGC (DFCHGC) micelles were 10.5% and 78.5%, respectively. The shape of DFCHGC micelles was almost spherical. DOX was released from DOX-loaded micelles in a biphasic manner, which displayed an initial rapid release phase and a later sustained release phase. The 50% inhibitory concentrations (IC50) of DOX, DOX-loaded CHGC (DCHGC) and DFCHGC micelles, incubated with folate receptor (FR)-negative A549 cells for 48 h, were 1.493, 0.620 and 0.974 μg·mL-1, respectively. Therefore, DCHGC micelles exhibited much more potent cytotoxicity against A549 cells than DFCHGC micelles. In FR-positive HeLa cells, the IC50 values of DOX, DCHGC and DFCHGC micelles were 1.398, 0.662 and 0.259 μg·mL-1, respectively. The DFCHGC micelles showed the greatest cytotoxicity among three DOX formulations for HeLa cells. And DFCHGC micelles exhibited greater cellular uptake than free DOX and DCHGC micelles in HeLa cells. CONCLUSION: The FCHGC micelles as a drug carrier for DOX delivery show selectively targeting to FR-positive cells, and improve the anti-tumor activity of DOX. These results suggested that FCHGC micelles could be a potential carrier for active targeting drug delivery.