Glycyrrhetinic acid-modified PEG-PCL copolymeric micelles for the delivery of curcumin

In this study, glycyrrhetinic acid (GA) was conjugated with mono amino poly (ethylene glycol)-b-poly (ε-caprolactone) (H2N-PEG-PCL) with succinate linker to obtain the GA-modified PEG-PCL (GA-PEG-PCL). By way of thin film hydration method, curcumin was encapsulated into GA-PEG-PCL copolymer to form stable micelles with 93.76% of encapsulation efficiency and 11.93% of drug loading capacity. The micelles enhanced curcumin's water-solubility to 1.87 mg/ml, being 1.70 × 105 times higher than free curcumin. X-ray diffraction and FT-IR analysis confirmed the encapsulation of CUR into copolymeic micelles with an amorphous state. Hemolysis datum of blank micelles showed its biocompatibility. Compared with GA-unconjugated micelles, curcumin-loaded GA-PEG-PCL micelles showed slower in vitro release of drug, but they displayed better in vitro cytotoxicity against HepG2 at about 40 μM because of its selective accumulation in HepG2 cells induced by GA. The results showed that GA-PEG-PCL copolymer could be a promising drug carrier for liver targeted drug delivery.