TPGS修饰载精氨酸脱亚胺酶环糊精脂质纳米粒的酶活性和药动学研究

目的考察D-α-生育酚聚乙二醇琥珀酸酯(D-α-tocopherol polyethylene glycol 1000 succinate,TPGS)修饰的载精氨酸脱亚胺酶(arginine deiminase,ADI)环糊精脂质纳米粒(TPGS-modified ADI cyclodextrin lipid nanoparticles,ACLN)的酶活性特性和药动力学特点。方法二乙酰一肟-氨基硫脲比色法测定ADI酶活性,双倒数作图法测定酶米氏常数。测定大鼠静脉给药后血浆中酶活性,绘制时间-酶活性曲线,采用DAS 2.1.1软件分析药代动力学数据。结果ADI和ACLN的酶催化反应的最适温度均为37℃,最适pH均为6.5,Km值分别为0.87、0.74 mmol·L^-1,V max值分别为53.28、62.50μmol·L^-1·min^-1,ACLN的V max为ADI的1.17倍。分析得ACLN的AUC(0-168 h)、MRT(0-168 h)、C max、T max分别为游离酶ADI的3.81、2.69、1.59、3.00倍,ACLN的相对生物利用度为381.42%。结论ACLN明显提高了ADI的酶活性和在大鼠体内的生物利用度。

Pharmacokinetic properties and in vitro enzyme activities of TPGS-modified arginine deiminase cyclodextrin lipid nanoparticles

Aim To investigate the pharmacokinetic properties and in vitro enzyme activities of D-α-tocopherol polyethylene glycol 1000 succinate-modified arginine deiminase cyclodextrin lipid nanoparticles(ACLN).Methods The diacetylmonooxime-thiosemicarbazide colorimetric method was used to determine the ADI enzyme activity,and the double reciprocal plot method was used to determine the enzyme Michaelis constants.After the rats were given intravenously free ADI and ACLN,rat plasma samples were taken at different time points to determine the activity of ADI,and the time-enzyme activity curve would be drawn and the pharmacokinetic data analyzed by DAS 2.1.1.Results The optimum temperature for ADI and ACLN was 37°C and the optimum pH was 6.5.The Km values of free ADI and ACLN were 0.87 and 0.74 mmol·L^-1,respectively.The V max values of free ADI and ACLN were 53.28,62.50μmol·L^-1·min^-1,respectively.The V max of ACLN was 1.17 times higher than that of ADI.The AUC(0~168 h),MRT(0~168 h),C max and T max in the ACLN group were 3.81-,2.69-,1.59-and 3.00-fold higher than those of ADI,respectively.The relative bioavailability of ACLN was 381.42%.Conclusion Compared with the free ADI,ACLN has a significant higher enzyme activity and bioavailability in rats.