The Pharmacokineitcs And Tissue Distribution Of （3aRS,4SR,7RS,7aSR）-2-(Tricyclo-[3.3.1.1^3,7]decan-1-yl)-4,5,6,7-tetrahydro-4,7-epoxyisoindoline-1,3-dione （SU2162）, Following Intravenous Administration In Rats

Using traditional Chinese medicine to treat diseases has a long history. It showsdistinct therapeutic effect. Cancer is the main cause of human death in the world.Mylabris as traditional Chinese medicine is used to cure cancer for many years.Cantharidin is a main active component, which is extracted from mylabris. Due to itsserious renal damage, its clinical use is limited. Norcantharidin, derived fromCantharidin, has a low toxicity and significance therapeutic activity for cancer. Inorder to reduce its toxicity, many derivatives of norcantharidin have been synthesizedand have showed significance therapeutic effect.The title compound （3aRS,4SR,7RS,7aSR）-2-（Tricyclo-[3.3.1.13,7]decan-1-yl）-4,5,6,7-tetrahydro-4,7-epoxyisoindoline-1,3-dione （SU2162）, is synthesized by a newmethod using norcantharidin and amantadine as raw material. It has the remarkableinhibitory effect on glioma growth, and shown a good dose effect relationshipbetween the effect of inhibiting glioma growth and the concentration of SU2162,IC50=0.721umol/l. Prof. ZaiYou Tan obtained patent license of SU2162in2008.Articles about the study of SU2162polymorphs have been published in magazines.Based on the above researches, the thesis was to study the pharmacokinetics and tissue distribution of SU2162after intravenous administration, the results were asfollows:1. A selective and sensitive high-performance liquid chromatography method hasbeen developed and validated for determination of SU2162in rat plasma and tissuesamples. The method of plasma and tissue samples disposal involved extraction anddeproteinization by acetonitrile, dryness under a stream of nitrogen, and reconstitutedwith acetonitrile. Chromatographic separation was achieved on a reversed-phase C18column using acetonitrile and water （40:60） as mobile phase at a flow rate of1.0ml/min. The assay was linear in the range of0.200-16.00μg/ml with a correlationcoefficient （r2） of0.9955. Limits of detection and quantification were0.204μg/ml and0.816μg/ml, respectively. The intra-day precision of the method was12.36%（low）,4.95%（middle）,8.61%（high）, the CV was less than15%, respectively. The inter-dayprecision of the method was6.31%（low）,8.63%（middle） and7.24%（high）, CV wasless than15%, respectively. The precision of the method was within the acceptablelimits. The accuracy of the method was113.26%（low）,114.24%（middle） and96.45%（high）, respectively. These results were in the rage of85%-115%, so it wasacceptable.The absolute recovery of SU2162in rat plasma was98.26%（low）,84.49%（middle） and65.95%（high）, respectively. the CV was10.21%（low）,4.85%（middle）and8.54%（high）, respectively. The absolute recovery of SU2162in rat heart was74.21%（low）,74.63%（middle） and93.27%（high）, respectively. the CV was1.29%（low）,1.12%（middle） and6.49%（high）, respectively. The absolute recovery ofSU2162in rat liver was71.80%（low）,85.84%（middle） and94.12%（high）,respectively. the CV was7.72%（low）,6.34%（middle） and3.23%（high）,respectively. The absolute recovery of SU2162in rat spleen was70.95%（low）,71.74%（middle） and80.88%（high）, respectively. the CV was2.15%（low）,4.33%（middle） and6.50%（high）, respectively. The absolute recovery of SU2162in rat lungrespectively was71.55%（low）,66.02%（middle） and93.77%（high）. the CV was11.96%（low）,7.21%（middle） and5.82%（high）, respectively. The absolute recoveryof SU2162in rat kidney was68.65%（low）,72.52%（middle） and68.63%（high）, respectively. the CV was7.70%（low）,6.74%（middle） and10.01%（high）,respectively. The absolute recovery of SU2162in rat brain was55.11%（low）,74.47%（middle） and93.70%（high）, respectively. the CV was7.62%（low）,3.42%（middle）and3.11%（high）, respectively. the absolute recovery of SU2162in plasma, heart,liver, spleen, lung, kidney, brain was greater than50%, the CV was less than15%, sothe absolute recovery of SU2162in plasma, heart, liver, spleen, lung, kidney, brainwere acceptable. The stability of SU2162in residue after stored in-20℃for4dayswas98.25%（low） and104.66%（high）. The stability of extracted plasma samples inreconstitution solutions after five freeze-thaw cycles104.79%（low） and101.48%（high）.2. The study of pharmacokinetics for SU2162after intravenous administration inrats has been accomplished. The plasma concentration of SU2162was determined byHPLC, the pharmacokinetic parameters were calculated with pharmacokineticsoftware3p97and kinetica. According to the AIC principle, the result was showedthat SU2162in rats was a two-compartment model, and weighting coefficient is1/c2.The compartmental parameters computed by3p97were as follows: the empiricalconstant A was6.7873mg/L, B was2.5753mg/L, the distribution rate constant （α）was6.50331/h, the slow disposition rate constant （β） was0.60781/h，the equationemployed to characterize these plasma concentration versus time data wasC=6.7873×e^-6.5033t+2.5753×e^-0.60781t. The apparent volume of distribution （Vc） was0.5874L/kg，the distribution half life （T1/2α） was0.1066h, the slow disposition half life（T1/2β） was1.1404h，transfer rate constant from central compartment to the superficialcompartment （K12） was3.1087h-1, transfer rate constant from superficialcompartment to the central compartment （K21） was2.2294h-1, elimination rateconstant from central compartment（K10）was1.7729h-1, the area under the plasmaconcentration time curve （AUC） was5.2808（mg/L）*h, clearance （CL） was0.3115L/h.The compartmental parameters computed by kinetica were as follows: time toreach maximum concentration （Tmax） was0h, maximum concentration （Cmax） was9.3621mg/l, the empirical constant A was6.7875mg/L, B was2.5747mg/L, the distribution rate constant （α） was6.50191/h, the slow disposition rate constant （β） was0.60761/h, transfer rate constant from central compartment to the superficialcompartment （K12） was3.1082h-1, transfer rate constant from superficialcompartment to the central compartment （K21） was2.2286h-1, elimination rateconstant from central compartment（K10） was1.7728h-1, the distribution half life（T1/2α） was0.1066h, the slow disposition half life （T1/2β） was1.1404, The eliminationhalf life （T1/2kel） was0.3910h, The apparent volume of distribution （Vc） was0.5874L/kg, the apparent volume of the plasma compartment at steady state （Vss） was1.4066L/kg, the area under the plasma concentration time curve （AUC） was5.2808（mg/L）*h, clearance （CL） was0.3115L/h。There was no significant differencebetween the parameters computed by pharmacokinetic software3p97and kinetica.The non-compartmental parameters computed by kinetica were as follows:maximum concentration （Cmax） was7.8157mg/l, peak time （Tmax） was0.05h, thearea under the plasma concentration time curve （AUC） was5.0774（mg/l）*h, the slopeof the terminal phase using log scale （Lz） was0.74981/h, half-life of elimination（T1/2） was0.9244h, mean residence time （MRT） was1.1961h, Clearance （CL） was0.3240L/h，the apparent volume of the plasma compartment at steady state （Vss） was1.2957L/kg, the apparent volume of distribution during the terminal phase （Vz）was1.4447L/kg。3. This thesis was to study the tissue distribution of SU2162after intravenousadministration in rats. The tissue samples concentration of SU2162was determinedby HPLC, the pharmacokinetic parameters were calculated by non-compartmentmodel in kinetica software.The results were showed that the AUC in spleen was the highest, which was6.7685（mg/l）*h, followed by liver and kidney. The values of AUC in liver and kidneywere2.6847（mg/l）*h and2.5829（mg/l）*h, respectively. The LZ in the liver was themaximum, which was1.57291/h；and the values of LZ in spleen were the minimum,followed with kidney. T1/2in liver was the shortest; and the T1/2in spleen was thelongest, followed by kidney. The MRT in liver was smallest, which was0.6760h; andthe MRT in kidney was the largest except spleen. The amount of SU2162in spleen was the largest; however, the elimination rate of SU2162in spleen was the slowest.These results indicated that a great number of SU2162accumulated in spleen. Theamount of SU2162in liver was the largest except spleen, and the elimination rate ofSU2162in liver was the fastest. It was showed that the metabolism of SU2162in liverwas the fastest in all tissues, and SU2162could target the liver. This result provedusing traditional Chinese medicine to treat liver cancer was based on science. Theamount of SU2162in kidney was close to the amount of SU2162in liver, but theelimination rate of SU2162in kidney was the slowest except spleen. Vss and Vz inliver were the smallest. These results demonstrated the amount of SU2162in liverwas the largest.Studying the pharmacokinetics and tissue distribution of SU2162afterintravenous administration, and understanding the pharmacokinetic behavior anddistribution characteristics of SU2162in rat, will help us to choose the best dosageform for SU2162and direct the clinical use of SU2162.