Studies On The Anti-Cancer Activity And SLN Delivery System Of Oridonin

Oridonin(ORI) is a new ent-kaurane diterpenoid isolated from Chinese traditional medicine Rabdosia Rubesecens (hemsl) which has been used in China for the clinic therapy of anti-tumor. Previous reports have shown ORI has many biological and pharmacological activities in home and aboard. In the present study, we studied the effects on the proliferation of cancer cells in vitro and in vivo and determined its possible mechanisms of action in cancer cells. Lastly, SLN(Solid Lipid Nanoparticles was developed to deliver ORI. The scope of thesis research included: (1) the study of the anticancer activity of ORI in vitro and in vivo and its possible mechanisms of action; (2) the design of the 0RI-SLN;(3) the character of the ORI-SLN;(4) the study of the anticancer activity of ORI-SLN in vitro and in vivo and its possible mechanisms of action; (5) the pharmacokinetics of the ORI-SLN in vivo.In this study MTT test showed that the proliferation of various tumor cells in vitro vas inhibited by ORI in a concentration- and time- dependent manner. The IC50 ranged from 7.4-55.1μM. The inhibition of K1735M2 melanoma cells was due to the arrest at the S and G2+M stage of the cell cycle by flow cytometer. The ORI induced apoptosis and long dendrite-like projections were observed. In addition, the study showed the migration of K1735M2 cells was decreased by ORI. All these results suggested that it might be a connection of various bio-effectiveness by which ORI inhibited tumor growth. The in vivo experiments indicated the ORI successfully inhibited the growth of implanted H₂₂,S₁₈₀,B₁₆ solid tumor proliferation and growth, but had a little effect on the Lewis solid tumor. Further research on the mechanism by which ORI inhibited the growth of solid tumors in vivo is on going.The emulsifying-evaporation method was used to prepare ORI-SLN. Based on the test of single factor, the formulation and the preparation techniques of ORI-SLN were optimized by the orthogonal design. The ORI content was detected by HPLC method. It was also used as a sensitive and reproducible method to determine the content of ORI in ORI-SLN, with a recovery of better than 100% and RSD of 1.55%. The encapsulation ratio of ORI-SLN was determined by ultracentrifugation method and the mean was 91.43ï¼…with RSD of 1.25ï¼…. The morphology of ORI-SLN was examined by transmission electron microscope. The size and zeta potential of ORI-SLN was determined by PCS method. The results showed that the ORI-SLN were uniform spheres. The content of ORI was 0.9642 mg/ml. The average size of ORI-SLN was 82.5nm with a polydispersity index of 0.28 and the zeta potential was -48.2 mv. We studied the stabilization of ORI-SLN after stored for 1, 3, 6 month. The results showed that the particle size and zeta potential had changed a little after stored for 6month. The ultracentrifugation method was used to study drug release of ORI-SLN in vitro and the curve fitting method was used to find the drug release equation. The results showed that the drug release of ORI-SLN in vitro fit Weibull equation well.The MTT test showed that the proliferation of the tumor cells in vitro was inhibited ORI-SLN in a concentration- and time- dependent manner with the IC₅₀ 6.4μM. The inhibition of K1735M2 melanoma cells was due to the arrest at the S and G2+M stage of the cell cycle by flow cytometer. The ORI-SLN induced apoptosis and long dendrite-like projections were observed. In addition, the study showed the migration of K1735M2 cells was decreased by ORI-SLN. The in vivo experiments indicated the ORI-SLN successfully inhibited the growth of implanted H₂₂,S₁₈,B₁₆,Lewis solid tumor proliferation and growth.After i.v. administration of a single dose of ORI and ORI-SLN, the pharmacokinetics were determined the DAS software. The results showed the both of them fit the three chambers model.