重组人尿激酶原药代动力学的研究

Pharmacokinetic Studies on Recombinant Human Prourokinase

第一部分 :采用交叉设计 ,自身比较 ,研究了猕猴静脉注射 0 .4 ,0 .8和 3.2mg·kg- 1 重组人尿激酶原 (rhprouk)或 1.2 8× 10 5IU·kg- 1 尿源性天然尿激酶 (un UK) (其中推注 15 %剂量 ,90min内恒速滴注 85 %剂量 )后血浆中单链尿激酶型纤溶酶原激活剂 (scu PA)和双链尿激酶型纤溶酶原激活剂 (tcu PA)的浓度随时间变化、代谢转化和各自的药代动力学 ,及代谢转化和药代动力学参数与剂量浓度的依赖关系 .结果表明给药后scu PA转化为tcu PA的速度与scu PA的剂量呈正相关性 .第二部分 :通过测定兔静脉推注加滴注1 2 5I rhprouk 0 .8mg·kg- 1 (其中 15 %剂量静脉推注 ,85 %剂量在 90min内滴注 ,比放射活性 2 .5 0 6MBq/mg)后不同时间体内各组织总放射性、TCA酸沉放射性 ,以及酸沉和总放射性的比值 ;胆汁引流物放射性累计排出量 ,尿和粪中累计排出量 ,及在体内外1 2 5I rhprouk与血浆蛋白的结合 .研究rhprouk在体内的分布、代谢及排泄情况 .结果表明rhprouk不与血浆中蛋白结合 ,代谢部位主要集中在胆、肾等部位 ,代谢产物主要随小便排出 .

Study 1 Changes in blood drug level, metabolism, and pharmacokinetics of scu PA and tcu PA were investigated in a double control and cross over study in monkeys following intravenous injections of rhprouk (0.4 mg/kg, 0.8 mg/kg and 3.2 mg/kg) and un UK (1.28×10 5 IU/Kg). A 10% dose of the total drug was injected intravenously and the remaining 85% was infused intravenously within 90 min. In all groups of rhprouk injection, we found that the increases in blood levels of u PA and scu PA were positively correlated with the doses of rhprouk. The in vivo production of tcu PA was dependent on the doses of rhprouk and the blood levels of scu PA. A significant increase in tcu PA blood level was only noted after rhprouk injection at 3.2 mg/Kg. On the other hand, the un UK injection induced only an increase in blood u PA level, while the blood scu PA level was constantly below LOQ. A significant variation was found in the drug clearance curves of u PA, scu PA and tcu PA among individual dose group of rhprouk within the 90 min infusion interval. The initial dose of intravenous injection (mg) and the dose rate of the intravenous infusion (μg/min) were critical in maintaining the blood levels of drugs. In rhprouk dose group of 0.4 mg/kg, the decrease in blood scu PA level was found to stabilize at 1 100 ng/mL within the infusion interval. In rhpro UK dose group of 0.8 mg/kg, the blood scu PA levels were maintained at 2 000 ng/mL within the infusion interval (infusion dose rate 9 μg/min). No significant metabolism from scu PA to tcu PA was found in this dose group, and a balance between the drug infusion and clearance was noted during the infusion. In rhprouk dose group of 3.2 mg/kg, the metabolism from scu PA to tcu PA was greatly increased, and we noted a steady increase in blood scu PA which plateaued between 3 000～7 000 ng/mL. These findings revealed that clinical treatment of rhprouk at 3.2 mg/kg was essential to maintain an optimal scu PA level in blood without causing excessive metabolism to tcu PA. In the dose groups of 0.4 mg/kg, 0.8 mg/kg and 3.2 mg/kg, the corresponding post infusion AUC (0.5 5h) of the blood scu PA levels were (2?140±540), (3?880±690) and (8?290±2?480) ng/(h·mL) ( p < 0.05) respecfively. The AUC (0.5 5h) of the blood total u PA levels were (2?320±500), (4?140±710) and (17?420± 3?110) ng/(h·mL), respectively ( P < 0.01 to P < 0.05). The AUC (0.5 5h) of the blood tcu PA levels were (180±60), (270±40) and (913±525) ng/(h·mL), respectively ( P < 0.05). Thus it is estimated from the blood AUC tcu PA /AUC u PA ratio that tcu PA production rates were 7.7 %, 6.5 % and 52.4% in respective dose group ( P < 0.05). Our data indicated that the in vivo production of tcu PA was dependent on the dose of rhprouk treatment and blood scu PA levels. It was possible that the active molecules in rhprouk treatment at 0.4 and 0.8 mg/kg were mainly prototype scu PA. The side effect of hemorrhage during rhprouk treatment at doses larger than 0.8 mg/kg could be attributed to the production of tcu PA in vivo. In the dose groups of 0.4 mg/kg, 0.8 mg/kg and 3.2 mg/kg, the corresponding post infusion Cmax of scu PA were (1 300±40), (2 730±340) and (6 320±1 040) ng/mL ( P < 0.05) respectively. The ( rapid phase half life (t 1/2 ) of rhprouk was approximately (8.6±8.6) h, (7.9±5.5) h and (6.0±5.2) h, respectively. The end phase t 1/2 were ( 3.3 ±0.8) h, (3.1±0.5) h and (2.4±0.4) h, respectively. No significant statistic difference in t 1/2 was noted amang dose groups. The longer t 1/2 observed in dose group 3.2 mg/kg was possibly linked to metabolism factors. Study 2 We have studied the tissue total radioactivity, TCA acid base radioactivity and TCA acid base radioactivity/tissue total radioactivity ratio at 10 min, 100 min, 5.5 h and 48 h after intravenous application of 0.8 mg/kg 125 I rhprouk (radioactive strength 2.506 MBq/mg) in rabbits. An initial 15 % of the total dos