柱前衍生化HPLC法检测兔血浆和肝组织中左卡尼汀及其代谢物的含量

Determination of L-carnitine and its active metabolites in rabbit plasma and hepatic tissue by precolumn derivatization HPLC

目的:建立兔血浆和肝组织中左卡尼汀(LC)及其代谢物的柱前衍生化高效液相(HPLC)的分析方法,检测兔内源性LC、乙酰卡尼汀(ALC)和丙酰卡尼汀(PLC)及单次灌胃后LC、ALC和PLC在血浆和肝组织的含量。方法:采用新西兰大耳兔,以1mL/kg的剂量单次灌胃给予左卡尼汀,在药前(0h)和药后取血浆(1、3、7h)和肝组织(7h),采用柱前衍生化HPLC法检测血浆和肝组织中LC、ALC和PLC的含量。结果:兔血浆和肝组织中LC、ALC和PLC的线性范围分别是2～200、0.2～40和0.1～8μmol/L;日内、日间精密度均小于4.12%;平均方法回收率在80%～95%之间。空白兔血浆LC、ALC和PLC的浓度分别为15.8、2.2和0.5μmol/L,空白兔肝组织的浓度分别为24.8、4.6和2.1μmol/g。给药7h后,LC、ALC和PLC在血浆和肝组织中的浓度明显升高。结论:本方法简单、可靠、精密度高。给药7h后,LC在体内的吸收过程中,发生了左卡尼汀乙酰化和丙酰化的过程,LC代谢成为ALC和PLC,并且其在肝组织中的浓度明显大于血浆,证明LC、ALC和PLC很快从血浆转移到肝组织中去。

AIM：To establish a method to determine the concentrations of L-carnitine （LC） and its active metabolites in plasma and hepatic tissue of rabbit by precolumn derivatization HPLC.It was detected the content that the LC and its active metabolites of endogenous and after a single dose by intragastrical administration.METHODS：A single dose of 1 mL/kg that LC was taken orally to New Zealand rabbits with big ears.The plasma and hepatic tissue samples were taken before and after administration respectively.The concentrations of LC and its active metabolites in plasma and hepatic tissues were measured using pre-column derivatization HPLC.RESULTS：The method showed good linear response over the selective concentration range of 2-200,0.2-40 and 0.1-8 μmol/L for LC,acetyl-L-carnitine （ALC） and propionyl-L-carnitine （PLC）,respectively.The intra-day and inter-day validations were less than 4.12% for three agents;The average methods recoveries of assay were 80%-95%.The plasma concentrations of LC,ALC and PLC in blank rabbits were 15.78,2.15 and 0.47 μmol/L,respectively,and their concentrations in hepatic tissue were 24.83,4.61,and 2.08 μmol/g,respectively.After administration for 7 h to rabbits,the concentrations of LC and its active metabolites have a significant change in plasma and hepatic tissue.CONCLUSION：This method is simple,reliable and accurate.These results show that in the absorption process of LC in vivo,LC is acetylated and propionylated,and transformed to active metabolites ALC and PLC.In hepatic tissue,concentrations of LC and its active metabolites are significantly higher than in plasma,indicating that LC and its active metabolites distributied are transfer from plasma to hepatic tissue quickly.