Preparation and evaluation of proliposomes formulation for enhancing the oral bioavailability of ginsenosides

Background: This research main objective was to evaluate a proliposomes (PLs) formulation for the enhancement of oral bioavailability of ginsenosides, using ginsenoside Rg3 (Rg3) as a marker. Methods: A novel PLs formulation was prepared using a modified evaporation-on-matrix method. Soy phosphatidylcholine, Rg3-enriched extract, poloxamer 188 (Lutrol (R) F 68) and sorbitol were mixed and dissolved using a aqueous ethanolic solution, followed by the removal of ethanol and lyophilization. The characterization of Rg3-PLs formulations was performed by powder X-ray diffractometry (PXRD), transmission electron microscopy (TEM) and in vitro release. The enhancement of oral bioavailability was investigated and analyzed by noncompartmental parameters after oral administration of the formulations. Results: PXRD of Rg3-PLs indicated that Rg3 was transformed from crystalline into its amorphous form during the preparation process. The Rg3-encapsulated liposomes with vesicular-shaped morphology were generated after the reconstitution by gentle hand-shaking in water; they had a mean diameter of approximately 350 nm, a negative zeta potential (-28.6 mV) and a high entrapment efficiency (97.3%). The results of the in vitro release study exhibited that significantly more amount of Rg3 was released from the PLs formulation in comparison with that from the suspension of Rg3-enriched extract (control group). The pharmacokinetic parameters after oral administration of PLs formulation in rats showed an approximately 11.8-fold increase in the bioavailability of Rg3, compared to that of the control group. Conclusion: The developed PLs formulation could be a favorable delivery system to improve the oral bioavailability of ginsenosides, including Rg3.