Preparation And Preliminary Evaluation Of HGRFG-SSL Liver Targeting Drug Delivery System

Objective Prepare SSL drug delivery system,detect its characterization,and evaluate its biodistribution and liver targeting activity in vivo.The HGRFG was encapsulated with SSL(HGRFG-SSL)and its characterization was detected,and the optimal drug-lipid ratio and drug release were explored.Evaluate the effect of SSL on the pharmacokinetics of HGRFG containing 5-Carboxyfluorescein(HGRFG-5-FAM).Investigate the effects of HGRFG and HGRFG-SSL on CCl4-induced acute liver injury in mice.Methods ①DiR-SSL was prepared by thin-film dispersion method,its particle size and polydispersity index(PDI)were detected,and its morphology was observed under electron microscope;②DiR-SSL were injected intravenously in normal BALB/c nude mice,at 1,2,5,7,24 h the mice were in vivo imaged and fluorescence values were read;③The normal SD rats were injected DiR-SSL intravenously,after 24 h,the heart,liver,spleen,lung and kidney were imaged in fluorescence imaging system and the fluorescence values were read,and the frozen sections of the liver tissue were observed by laser confocal microscopy;④The HPLC method was established for the determination of HGRFG;⑤The thin-film dispersion method was used to prepare the HGRFG-SSL and the characterization was performed,and the optimum drug-lipid ratio was selected by ultrafiltration-centrifugalization;⑥The in vitro drug release of HGRFG-SSL at different time points was investigated by dialysis method;⑦HF-SSL(HFL)was prepared by thin-film dispersion method,the plasma HF concentration in rats administrated respectively by HF and HFL were measured at different time points,and the relative pharmacokinetic parameters were calculated;⑧The mice were pretreated with HGRFG,SSL and HGRFG-SSL for one week.In comparison to bifendate as positive medicine,the effects of different drugs on mice acute liver injury induced by CCl4 single administration were investigated.Results ①The particle size of DiR-SSL was about 100 nm,the PDI was 0.099,the electron microscopy showed the liposomes were spherical and evenly distributed;②DiR-SSL in BALB/c nude mice was metabolized gradually over time,but in vivo imaging of fluorescence showed liposomes were mainly in the liver;③DiR-SSL total fluorescence in the liver of SD rat was stronger than other organs,and DiR-SSL was widely distributed in liver frozen sections;④The appearance time of HGRFG was at 6.389 min with a good symmetrical peak shape,and the standard curve had good linear correlation;⑤The particle size of HGRFG-SSL was around 100 nm,the PDI was 0.083,the electron microscopy showed the shape was good,the results of ultrafiltration-centrifugalization showed that the optimal drug to lipid ratio was 1:5 and the encapsulation efficiency was 38.80%;⑥The release rate of HGRFG reached the highest at 4 h,after that the release rate tended to be stable,and the released drug content was closed to the total amount of unencapsulated drugs;⑦HFL significantly increased T1/2 in SD rats compared with HF,and reduced the plasma clearance;⑧The levels of serum AST and ALT in mice were significantly higher in CCl4 group than those in control group,the bifendate group significantly reduced ALT levels,and the levels of AST and ALT in HGRFG,SSL and HGRFG-SSL groups were not significantly different from those in CCl4 group.Serum TNF-α and IL-6 levels of all drug-treated groups increased.Liver histopathological analysis showed that bifendate group had the most obvious alleviated effects among all drug groups.Conclusion In this experiment,the SSL drug delivery system was successfully prepared,and the SD rats and the BALB/c nude mice confirmed the significant liver targeting effect of the SSL drug delivery system.The characterization of HGRFG-SSL was satisfactory,the highest entrapment efficiency was obtained at the drug-lipid ratio of 1:5,and drug release test indicated that HGRFG in the inner water phase of liposomes could not release by diluting in pH 7.4 PBS.The results of pharmacokinetic experiments showed that SSL enhanced the T1/2 of HGRFG in SD rats and improved the effective time of drug,and HGRFG and HGRFG-SSL did not show a significant effect on alleviating acute liver injury induced by CCl4 in mice.