Experimental Study Of Cucurbitacin Solid Lipid Nanoparticles

Solid lipid nanoparticles(SLN) is a promising drug delivery system with natural or synthetic lipid as drug carrier, which could be used for topical, oral and parenteral administration and had the advantages of ideal targeting effects, low speed of drug leakage, good physical stability and low toxicity, etc. The aim of this thesis was to investegate cucurbitacin-loaded solid lipid nanoparticles.First, a HPLC method with acetonitrile-0.06 mol/L KH2PO4(45:55, v/v) as mobile phase was established to determine the content of cucurbitacin B in cucurbitacin SLN, and coagulation-centrifuge method was established to determine the entrapment efficiency of cucurbitacin SLN.This thesis used physiology endurance high melting point lipid-stearie acid glyceride and precirol ATO 5 as drug carrier, poloxamer 188 as emulsifiers. The supersonic-compression filter method was used to prepare the stable SLN. The prescription and the method to prepared SLN were optimized by single factor exploration and comprehensive design.The quality of the cucurbitacin SLN suspension was evaluated. The results showed that the cucurbitacin SLN suspension prepared in this thesis had sky-blue color and was well distributed with a drug concentration of 440.9mg/L, a z-average diameter of 108.3nm, PDI of 0.221, a zeta potential of -17.43mv, an encapsulation efficiency up to 98.74%, a drug-loaded capacity of 0.987% and a pH value of 6.52. By using particle size and PDI as investigation index, the physical stability of cucurbitacin SLN was studied in many conditions such as high temperature, sterilization, acceleration, low and room temperature, and the results showed that the cucurbitacin SLN had a good stability for at least 120 days in room temperature and dark conditions.The metabolism of cucurbitacin B in homogenized tissues of rats in vitro was studied and the drug concentration was determined by a RP-HPLC method.The results showed that cucurbitacin B was metabolismed quickly in the homogenized tissues of heart, liver, lung,kidney,stomach and brain. However, only the degradation of cucurbitacin B in homogenized heart was followed pseudo-first order kinetics with a half-life of 23.98min.SK-N-SH cell line was cultured in vitro, then treated with different concentrations of cucurbitacin solution and cucurbitacin SLN. The cell proliferation was analyzed with MTT assay, the cell morphous were observed by inverted microscope, and the progression of cell cycle was tested by Flow cytometry. The-results showed that the growth of SK-N-SH cell line was obviously inhibited by cucurbitacin solution and cucurbitacin SLN at different concentrations with concentration-dependent. IC50 of cucurbitacin solution and cucurbitacin SLN was 7.023mg/L and 0.284 mg/L respectively. Compared with those of DMSO group, the cell density of cucurbitacin and cucurbitacin SLN groups decreased,the cell volume reduced, and the form of majority cell changed. Flow cytometry assay suggested that cucurbitacin solution retarded the progression of cell cycle at G2/M and S phase,and cucurbitacin SLN only retared the progression of cell cycle at G2/M phase.