Preparation Of Tanshinone ⅡA Polymer Lipid Nanoparticles And Preliminary Pharmacokinetic Study

Objective:As the main active component of Salvia miltiorrhiza,tanshinone ⅡA（TanⅡA）is widely used in the treatment of cerebrovascular diseases such as hemorrhagic stroke because of its unique antioxidant,anti-inflammatory and neuroprotective effects.However,the low solubility and high lipophilicity of TanⅡA seriously limit its application.In this study,polymer-lipid hybrid nanoparticles（PLNs）were used as carriers to deliver TanⅡA for increasing solubility,bioavailability and drug accumulation in the brain,which combine the structural advantages of liposomes and polymer nanoparticles.Methods:An in vitro analysis method was established by HPLC for the subsequent determination of TanⅡA and the quality evaluation of TanⅡA-PLNs;besides,the drug-loaded PLNs and free drugs were separated by ultracentrifugation to determine the entrapment efficiency of Tan ⅡA-PLNs.Tan ⅡA-PLNs were prepared by nanoprecipitation;and the single factor investigation was used to optimize the prescription and process with entrapment efficiency and particle size as indexes.The quality of Tan ⅡA-PLNs was evaluated by appearance,particle size,particle size distribution,surface potential,DSC,in vitro release and stability test.The in vivo analysis method of LC-MS/MS was further established,and the blood concentration of Tan ⅡA-PLNs in rats at different time points was investigated,comparing with Tan ⅡA.Meanwhile,the accumulation of Tan ⅡA-PLNS in the brain of mice was observed.Finally,TANIA-PLNs were labeled by DIR and their distribution in tissues was observed by in vivo imaging of small animals.Results:The optimum preparation conditions of Tan ⅡA-PLNs were as follows:Tan ⅡA:Egg-PC:PLGA was 1:4:1.6,and the volume ratio of organic phase to water phase was 1:15.The confirmatory experiment with this method showed that the preparation method was stable.The prepared Tan ⅡA-PLNs were uniform and stable;and the particle size,PDI,zeta potential,and entrapment efficiency were 271.3 nm±6.2,0.0242,-4.93mv,88.2%±1.76,respectively.The in vitro release behavior showed that the release rate of Tan ⅡA-PLNs was significantly lower than that of Tan ⅡA,and the release tended to be stable after nearly 400 hours with the cumulative release rate reached 89.44%±2.22,indicating that PLNs had a certain sustained release effect.In vivo pharmacokinetic experiments showed that although the dose of oral Tan ⅡA raw drug was 5 times higher than that of tail intravenous injection of Tan ⅡA-PLNs,the AUC and T_1/2of Tan ⅡA-PLNs were 2.8 times and 1.5 times higher than that of Tan ⅡA raw drug,respectively.In addition,brain tissue assay and in vivo imaging showed that Tan ⅡA-PLNs have a good effect on the distribution of brain tissue.Conclusion:Tan ⅡA-PLNs were successfully prepared,and their state were uniform and stable with high encapsulation rate.In vitro,it had obvious sustained-release effect.In vivo pharmacokinetic parameters and drug brain tissue distribution showed that Tan ⅡA-PLNs could significantly prolong the terminal of Tan ⅡA,improve bioavailability,and increase accumulation of drug in brain.