| Objective: To understand the change of metabolism in rats and evaluate safety of Non-hemorrhagic Fibrinolytic Enzyme (NHFLE) from Agkistrodon Acutus by general pharmacology, pharmacokinetics and toxicology research, and provide foundation for clinical trials and application.Methods: 1. NHFLE was injected intravenously at the tail into mice with the doses of 2.0, 1.0 and 0.5mg/kg respectively. The same administration method was used to rats but with the different doses of 1.4, 0.7 and 0.5mg/kg. The saline was gave as the control group. We observed the changes in general behavior, coordinate activity and synergism with sodium pentobarbital at subthreshold dose of mice. To rats, we observed the heart rate, cardiac electric voltage, mean arterial pressure, respiratory rate and depth and clotting time. 2. During pharmacokinetics research, NHFLE was labeled with 125I by the method of Chloramine-T. After purificationusing Sephadex G-50, 125I-NHFLE was separated and then the radiochemicalpurity of I-NHFLE was assayed by y -counter. After intravenous administration of l25I-NHFLE to rats, the plasma samples of 125I-NHFLE, the distribution in tissues or organs and the excretion in urine, feces and bile were studied with via radioactive tracer technique respectively. 3. The acute toxicity of NHFLE was studied on Kunming species mice. 4. Experimental animals of long-term toxicity were healthy Wistar rats. Route of medication was intravenous injection with 9.0, 4.5 and 2.25mg/kg by three different dosages of high dose group, middle dose group and low dose group, while the saline was gave as the control group.Results: 1.A11 the animal groups of mice showed that NHFLE had no influence on their general behavior, coordinate activity and synergism with sodium pentobarbital at subthreshold dose after intravenous injection. The nervous, cardiovascular and respiratory systems in rats after administrated at different doses of NHFLE were normal. The blood clotting time of the rats at high dose of NHFLE was delayed obviously after injection 10-30 min (P<0.05 ) but changed normal at 60 min, meanwhile there was no significant difference of blood clotting time inother groups. 2. Radiospecific activity of 125I-NHFLE was 25.8GBq/L. The labelled ratio was 7.318MBq per milligram NHFLE. After intravenous injection at doses of 1.4 0.7 0.35mg/kg to rats, the main pharmacokinetic parameters of I-NHFLE were as follows: T1/2a was between 0.626~0.672h and t1/2B was between 10.384~13.818h. AUC were 7073.03 + 124.14, 3920.00 + 549.64 and 3315.78+125.30 ug hL-1. There were no significant differences of t1/2a and t1/2B among the three dose groups (P>0.05) , but the AUC increased markedly with the dose increase (P<0.05) .The concentration-time curves of 125I-NHFLE were conformed to two-compartment model. The amount of radioactivity excreted in urine, feces and bile within 24h after intravenous administration of I-NHFLE to rats was 75.31%, 3.29% and 6.45% of the dose respectively. Within 48h after administration drug 86.22% of 125I-NHFLE was excreted in urine and 4.98% in feces. The peak concentration of 125I-NHFLE in tissues or organs appeared at Ih. Following intravenous injection to rats, the radioactivity was selectively distributed to kidney, thyroid, liver, spleen and stomach, while the levels in brain, adipose and muscle were low. 3. Acute toxicity experiment showed that LD50 of NHFLE was 28.84mg/kg in mice. 4. Long-term toxicity experiment showed that during the 4 weeks of intravenous administration, the rats of high dose group had more activity, dysphoria, slight diarrhea and less weight increase than the control group ( P<0.05) and were recovered in 2 weeks withdrawal. Rats' weight increase, appearance and behavior were normal in other groups. There was no significant abnormality in hematology and laboratory test. The organ coefficients and pathologic examination were normal in all groups.Conclusions: The drug has no effects on nervous, cardiovascular and respiratory systems. The half-lives of two phases were no statistically differenc... |
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