Pu^(4+)在人体血浆中分布的计算机模拟研究

Computer Simulation of Pu^(4+) Speciation Distribution in Human Blood Plasma

建立了由多种金属离子和小分子配体组成的多相人体血浆热力学平衡模型,并用该模型模拟研究了Pu4+在血浆中的形态分布及二乙三胺五乙酸(DTPA)和CO2-3、Citrate3-浓度对细胞液中Pu4+形态分布的影响。结果显示,血浆中的低浓度Pu4+易以Pu(OH)4(l)的形态蓄积在肝脏中,钚浓度升高则形成沉淀Pu(OH)4(s),难以排出体外。在DTPA浓度为2.5×10-5 mol/L时,血浆中水溶性小分子[Pu(OH)DTPA]2-含量达到最高并保持稳定。酸性条件下随着Citrate3-浓度的升高,血浆中Pu4+与Citrate3-结合形成可溶性的[PuCitrate2]2-和[PuCitrate]+的离子化合物。DTPA浓度大于4.6×10-5 mol/L时,血浆中的DTPA以与Ca2+、Mg2+结合形成的[CaHDTPA]2-、[Ca2DTPA]-、[CaDTPA]3-、[MgHDTPA]2-、[MgDTPA]3-小分子结合态为主。

A thermodynamic equilibrium model consisted of multi-metal ion and low molecular-weight ligand was constructed to study the speciation of Pu4+in human blood plasma and the influences of concentrations of DTPA,CO2-3and Citrate3-on the speciation.Computer simulation indicates that low concentration of Pu4+in blood plasma with Pu(OH)4(l)speciation accumulates in liver.Pu4+form precipitation is difficult to eliminate from the body under the high concentration of Pu4+in plasma fluids.When the concentration of DTPA is 2.5×10-5 mol/L,the species of plutonium is mainly as negatively charged[Pu(OH)DTPA]2-and maintains stable.The species was at firstcalculated at pH 5.0,with the increase of concentration of Citrate3-,the major speciation of Pu4+is as[PuCitrate2]2-and[PuCitrate]+which are excreted easily from body.In blood plasma Pu4+combines with Ca2+and Mg2+to form [CaHDTPA]2-,[Ca2DTPA]-,[CaDTPA]3-,[MgHDTPA]2-and[MgDTPA]3-when the concentration of DTPA is 4.6×10-5 mol/L,which excrete Pu4+and produce toxic side effects on bone at the same time.