Intranasal Delivery of Microspheres Loaded with 20 (R)-ginsenoside Rg3 Enhances Anti-Fatigue Effect in Mice

BACKGROUND: Nasal delivery of 20 (R) -ginsenoside Rg3 (Rg3) has a short-lived anti-fatigue effect owing to rapid clearance by nasal cilia. Thus, in order to extend the residence time of Rg3 in the nasal cavity, a new drug delivery system is needed. METHODS: Chitosan microspheres loaded with Rg3 were prepared using a multi-step emulsification method and were characterized in vitro and in vivo. RESULTS: The microspheres had a spherical shape with a mean diameter of 44.9±12.6 08m. The drugloading ratio was 10.25±0.08%, and the encapsulation ratio was 30.61±1.46%. Our in vitro mucoadhesion experiment demonstrated that 70.35±1.79% of the microspheres adhered to the nasal mucosa. The in vitro release study revealed that 31.1% of the Rg3 was released from the microspheres in the first 10 min. Release slowed, with 88.64% of the Rg3 released within 6 h. The pharmacodynamics study demonstrated that the weight-bearing swimming time of mice increased significantly from 432±89 s to 486±96 s after administration of Rg3 microspheres compared with the Rg3 water solution. Blood lactic acid and serum urea nitrogen significantly decreased in the group administered microspheres compared to the water solution group (p<0.05). Hepatic glycogen and lactate dehydrogenase increased significantly in the group administered microspheres compared to the water solution group (p<0.01). CONCLUSION: 20 (R) -ginsenoside Rg3 entrapped in chitosan microspheres may have a beneficial effect against fatigue by increasing the residence time of Rg3 in the nasal cavity and enhancing absorption by the nasal mucosa.