Preparation And Preliminary Pharmacokinetic Study Of Tanshinone ?A And Tetramethylpyrazine Composite Nanoemulsion

OBJECTIVE: Tanshinone ?A(TSN)is a major liposoluble compound of Salvia miltiorrhiza.It has a good therapeutic effect on cardiovascular and cerebrovascular diseases such as coronary heart disease,cerebral thrombosis and angina pectoris.However,TSN also has the disadvantages of low solubility and low oral bioavailability.Tetramethylpyrazine(TMP)is the primary active substance of Chuanxiong.It is widely used in the treatment of cardiovascular and cerebrovascular diseases because of its pharmacological effects which included antithrombotic,anti-ischemic and reperfusion injury,protection of cardiovascular and cerebrovascular system.Nanoemulsion(NE)has the characteristics of simple preparation process and high safety.It can also improve the solubility,stability and bioavailability of poorly soluble drugs when used as a carrier.In addition,its special particle size distribution and structural composition also make it certain sustained release and passive targeting.In this study,tanshinone ?A and tetramethylpyrazine composite nanoemulsion(TMP-TSN-O/W NE)were prepared to improve the solubility and bioavailability of TSN.Besides,the brain targeting and the cytotoxicity to glioma cells of nanoemulsion were investigated after adding TMP.Methods: Firstly,medium chain triglyceride was used as oil phase,polyoxyethylene castor oil was used as emulsifier,and 1,2-propanediol was used as auxiliary emulsifier to prepare TMP-TSN-O/W NE.The particle size and polydispersity coefficient were measured by Malvern laser particle size analyzer,the morphology was examined used transmission electron microscopy,and the in vitro release behavior was investigated by in vitro release study.The plasma concentration of TMP-TSN-O/W NE in rats was investigated compared with TSN and tanshinone ?A nanoemulsion(TSN-O/W NE),and the pharmacokinetic parameters were calculated;Compared to the TSN and TSN-O/W NE,the distribution of TSN in the body was investigated,mainly to studied whether TMP improved the drug concentration of TSN in the brain tissue.The cytotoxicity of TMP-TSN-O/W NE were studied in the glioma cells U87 which the blank NE,TSN,TMP,physical mixture and TSN-O/W NE were used as control group.RESULTS: The average particle size of TMP-TSN-O/W NE was 33.2 nm,the polydispersity coefficient was 0.148,and the encapsulation efficiency was 95.26%.The morphology was spherical by transmission electron microscopy.Compared with TSN,TMP-TSN-O/W NE have sustained release effect;the AUC?MRT and t1/2 of the TMP-TSN-O/W NE were 5.69?6.56 and 6.56 times to TSN respectively in pharmacokinetic experiments study in rats.The rat tissue distribution study found the content of TSN in TSN-O/W NE and TMP-TSN-O/W NE group in the brain of were significantly higher than in TSN group at each time point.At 30,60,120 and 240 min,the TSN content in the TMP-TSN-O/W NE group was 1.44,1.44,1.63,1.34 times that of the TSN-O/W NE group,respectively.Compared with TSN and TSN-O/W NE,the peak concentration ratio of TMP-TSN-O/W NE was significantly improved,indicating that it has certain brain targeting properties.Cytotoxicity test results showed that for glioma cell U87,TMP-TSN-O/W NE group had stronger cell inhibition rate than other control groups.Conclusion: This topic successfully prepared TMP-TSN-O/W NE.,its physical and chemical properties have changed compared to TSN,the pharmacokinetic parameters in vivo have been improved,it has certain brain targeting,and it has strong cytotoxicity for cancer cells.