Abstract:

BACKGROUND: Polymeric micelles have a solubilization capacity for insoluble drugs and are suitable carriers of anticancer drugs. Surface modification of polymeric micelles with folic acid could facilitate cellular uptake in folate receptor-positive tumor cells. 
OBJECTIVE: To prepare and characterize folate-conjugated micelles incorporated with hydrophobic drugs.
METHODS: Polymeric micelles containing coumarin 6 were prepared using thin-film hydration method. Coumarin 6, methoxy polyethylene glycol-phosphatidylethanolamine and folate-polyethylene glycol-phosphatidylethanolamine were dissolved in chloroform/methanol and the organic solution was evaporated by rotary evaporator, then the polymer thin-film was developed, followed by vacuum drying overnight. Hepes buffer solution was added to the thin-film and stirred by magnetic stirrer at 50 ℃ for 30 minutes. Meanwhile, plain micelles without folate-polyethylene glycol-phosphatidylethanolamine were also prepared. Plain micelles and folate-conjugated micelles were characterized, including the morphology by transmission electron microscopy, particle size distribution by dynamic light scattering and drug loading and encapsulation efficacy by high-performance liquid chromatography.
RESULTS AND CONCLUSION: The size of plain micelles and folate-conjugated micelles was about 60 nm under transmission electron microscopy. The mean particle size of plain micelles and folate-conjugated micelles was about 100 nm by dynamic laser scattering. The drug loading and encapsulation efficacy of micelles was about 0.7% and 15%, respectively. Polymeric micelles have significant solubilization effect for unsoluble drugs, and can be used to evaluate the folate receptor targeting in vitro and in vivo.