Enhanced dissolution rate and oral bioavailability of ginkgo biloba extract by preparing nanoparticles via emulsion solvent evaporation combined with freeze drying (ESE-FR)

Abstract

Ginkgo biloba extract nanoparticles were successfully prepared by the method of emulsion solvent evaporation combined with freeze-drying (ESE-FR). By the single-factor method, the optimal parameters were determined: the concentration of GBE was 5 mg mL⁻¹, volume ratio of water to organic phase was 1 : 1, homogenate speed and time were 12 000 rpm and 3 min, respectively, and homogeneous pressure and times were 500 bar and 3, respectively. The mean particle size (MPS) of the GBE nano-emulsion prepared using the optimized conditions was 56.0 nm. SEM detection results indicated that the morphology of raw GBE was irregular. But the morphology of GBE nanoparticles was close to spherical and the particle size of GBE nanoparticles was much smaller than that of raw GBE. The particle size of the freeze-dried powder was 277.0 nm. The characteristics of prepared GBE nanoparticles were detected via XRD, DSC and TG, which showed that the crystal structure of GBE nanoparticles was the same as that of raw GBE. Through the test of solubility and dissolution in vitro, the solubility and dissolution of GBE nanoparticles in artificial gastric juice, artificial intestinal juice and deionized water were obviously improved compared with that of raw GBE. The results of bioavailability showed that the Area Under Plasma Concentration Curves (AUC) of flavonoids and terpene lactones in GBE nanoparticles were improved about 1.81 times and 1.75 times compared with that in raw GBE, respectively. In addition, the residual amounts of chloroform and ethanol were less than the ICH limit for class II.