Development of a safety and efficacy nanoemulsion delivery system encapsulated gambogic acid for acute myeloid leukemia in vitro and in vivo.

This study aimed to improve the solubility, reduce the side effects and enhance the efficacy of gambogic acid against acute myeloid leukemia in vitro and in vivo. This oil-in-water nanoemulsion (average size 17.20 ± 0.11 nm, zeta potential 4.17 ± 0.82 mV) containing Tween-80, glycol, squalene and gambogic acid with improving 4000 times solubility was prepared by pseudoternary phase diagrams. We found that this nanoemulsion successfully encapsulated gambogic acid; it was stable and showed an obvious delayed release effect for the drug in three different phosphate-buffered saline (pH = 2.0, 5.8 and 7.4). The half inhibiting concentration (IC) of this nanoemulsion (480.7 μg/mL and 408 μg/mL) were 1.67 times and 1.98 times higher than those of its water solution (287 μg/mL and 206 μg/mL) after acting on the toxicity standard cell line (L929 line) for 24 h and 48 h, respectively. Importantly, acute injection toxicity indicated that the half lethal dose (LD) of this nanoemulsion (23.25 mg/kg, 95% LD, 21.7-25.16 mg/kg) was 1.26 times higher than that of its water solution (18.59 mg/kg, 95% LD, 16.84-20.53 mg/kg). Compared with its suspension, the bioavailability of this nanoemulsion was 318.2%. Furthermore, this nanoemulsion had a better efficacy against the acute myeloid leukemia in vitro and in vivo by improving the time and percent of survival (MV4-11 engrafts mice) and reducing half inhibiting concentration values in acute myeloid leukemia such as Jurket, HL-60 and MV4-11 cells. Our studies suggested that this nanoemulsion may be a promising therapeutic medicine for acute myeloid leukemia.