Studies On The Preparation,in Vivo And In Vitro Evaluation And Curing Of Ginkgolide B Nanosuspension

Ginkgolide B（GB）is one of the important active components of Ginkgo biloba extract,which has a good protective effect on the central nervous system.However,GB has poor water solubility and low oral bioavailability,which limits its clinical application.In this study,ginkgolide B nanosuspension（GB-NS）was prepared to improve its poor solubility.Meanwhile,we explored its effect on improving mice cognitive dysfunction.To improve the physical stability of GB-NS and increase the drug loading,it was prepared into a lyophilized powder and loaded into the orodispersible film（ODF）.The main research contents are as follows:In this study,the GB-NS was prepared by the miniaturized milling method.The formulation and process of GB-NS were optimized by single factor experiment and Box-Behnken design-response surface method,with the mean particle size（PS）and polydispersity index（PDI）as indexes.The average PS and PDI of the three batches of GB-NS prepared by the optimal formulation were（180±7）nm and 0.196±0.036.Scanning electron microscope（SEM）showed that GB-NS was irregular granule and rod-like in shape.X-rays diffraction（XRD）showed that the crystallinity of GB-NS was significantly reduced compared with GB raw material.The cumulative dissolution rate of GB-NS reached 90%in 30 min.The result of stability investigation showed GB-NS is stable within 10 days.The single-pass perfusion model was established in rats to investigate the intestinal absorption characteristics of GB-NS.The results showed that the best absorption of GB-NS was in duodenum segment,followed by jejunum segment and colon segment,and the worst absorption was in ileum segment.Compared with raw GB,the K_a and P_app of GB-NS had a significant improvement（P<0.01）,indicating the technology of nanosuspension can improve the absorption of GB in the intestinal tract.To investigate the improvement effect of GB-NS on learning and memory ability of cognitive dysfunction model mice.Morris water maze test was used to conduct behavioral investigation.The contents of relative enzymes in brain tissue of mice were determined by ELISA,and the pathomorphological changes of hippocampal CA1region were observed by Nissl-staining.The results showed that compared with the model group,the escape latency of GB-NS group was significantly decreased（P<0.01）,the levels of SOD,GSH-PX,CAT and Ach in brain tissue were significantly increased（P<0.01）,the levels of MDA and ACh E were significantly decreased（P<0.01）,and the damage of neurons cells in hippocampal CA1 region was significantly improved.Compared with the raw GB,the cognitive dysfunction of the mice in the GB-NS group improved more significantly,and the difference was statistically significant（P<0.05 or P<0.01）.The prepared GB-NS could significantly improve the effect of GB on cognitive dysfunctionGB-NS was freeze-dried and prepared into ginkgolide B nanosuspension lyophilized powder（GB-NS-LP）,and then loaded into ODF.Ginkgolide B nanosuspension lyophilized powder orodispersible film（GB-NS-LP-ODF）was used by solvent casting method and its formulation was optimized using the single factor combined with orthogonal test.The appearance,mechanical properties,content uniformity and in vitro dissolution of the optimized GB-NS-LP-ODF were investigated.According to the optimal formula,the GB-NS-LP-ODF prepared with GB-NS-LP35.6%,PVA 0588 49.4%,PEG 400 10.7%and CMS-Na 4.3%completely disintegrated in about 30 s,and the particle size of reconstituted GB nanoparticles from ODF was about 210 nm;The film with smooth appearance and good mechanical properties was stable within 30 days and the content uniformity（A+2.2S<15）conformed to the regulations;SEM showed that well-dispersed GB nanoparticles were observed in the films and the particle size was about 200 nm.XRD showed that its crystallinity was significantly lower than that of GB raw drug and GB-ODF;The results of in vitro dissolution test showed that the film was completely dissolution within 10 minutes.The experimental results showed that GB-NS-LP-ODF can improve the stability of liquid preparation and had a good application prospect.