Effect Of Hepatic Blood Flow Blocking On Drug Drug Pharmacokinetics

Objective:By assessing the effect of Pringle blocking, semi-liver blood flow blocking, infrahepatic inferior vena cava combined semi-liver blood flow blocking and the control group on metabolic speed of5-Fu and Clindamycin Phosphate in rabbits, we studied the effect of hepatic blood flow blocking on pharmacokinetics of the two drugs. As a result, we could provide experimental and theoretical guidance for clinical surgery medication in hepatic blood flow blocking operation, so as to avoid the adverse effect caused by drug accumulation.Methods:Animal experiment methods:Drug administration and blood sample collection:80healthy mature rabbits, regardless of sex, body weight1.5-2.5kg, were randomly divided into2groups---injecting5-Fu(1) and injecting Clindamycin Phosphate(2), then the2groups were randomly divided into4groups respectively, namely non blood flow blocking group, Pringle blocking group, semi-liver blood flow blocking group and infrahepatic inferior vena cava combined semi-liver blood flow blocking group,10rabbits each. Non blocking group was administered after intubation, blocking groups were administered after blocking,(1) were administered5-Fu,(2) Clindamycin Phosphate. The blood samples were collected from jugular vein5,10,20,30minutes after administration, each time2ml, the collected blood samples were stored in heparin tube at5℃in refrigerator till the whole blood samples were collected.Establishment of detection method: Chromatographic conditions were:group1(injection of5-Fu), the HPLC system consisted Diamonsil C18column (250mmX4.6mm,5μm), mobile phase:water-methanol (93:7), flow rate:1.Oml/min, column temperature:30℃, UV detection wavelength:254nm, injection volume was20μL; group2(injection of clindamycin phosphate), the HPLC system consisted Diamonsil C18column (250mmX4.6mm,5μm),mobile phase:30mmol/L hydrochloric acid three ethylamine (pH=2.65): acetonitrile (80:20V/V), flow rate:1.0ml/min, column temperature:30°C, UV detection wavelength:210nm, the injection volume was20μL. The establishment of the standard curve:standard solution was added into the blank plasma to prepare the concentration of100,50,25,10,5,1μg· ml-1series of standard solution, according to the internal standard sample handling methods to deal with sample injection measurements. The maps were collected, the peak area and related parameters were recorded in N3000Chromatography Work Station. The linear regression equation of As/Ai vs sample concentration C wras calculated., the standard curve regression equation and correlation coefficient was obtained.Blood sample procession:take200μL blood with pipettor in Centrifuge tube, then precisely add in50μL inner standard solution (100.0μg·mL-1), Vortex vibration for2min, add in50μL20%perchloric acid, Vortex vibration for1min, mix homogeneously, centrifuge for20min in high-speed centrifuge(15000r/min), the supernatants were transferred into2ml centrifuge tube immediately for testing.Results:This paper studied pharmacokinetics characteristics of5-Fu and Clindamycin Phosphate in simulated A(non-blocking)、B(infrahepatic inferior vena cava combined semi-liver blood flow blocking)、C (semi-liver blood flow blocking)、D(pringle method) in rabbits, and the data were analyzed using3p97pharmacokinetics statistical software, compartment model showed that:the phannacokinetics of rabits all fitted a two-compartment open model with first-order absorption after intravenous injection of5-Fu and Clindamycin Phosphate at a dose of2mg/kg and5mg/kg respectively. The main pharmacokinetic parameters of A、B、C、D four groups for5-Fu group respectively were as follows: Distribution half-life were3.15±0.31min、5.15±0.29min、6.04±0.37min、10.53±0.26min. Peak concentration were54.99±0.41mg/L、56.48±0.28mg/L、57.34±0.43mg/L、59.29±0.33mg/L. Apparent volume of distribution were2.46±0.31L/kg、1.81±0.41L/kg、1.49±0.29L/kg、0.61±0.52L/kg. Clearance rate were0.018±0.007L/min0.017±0.005L/min/、0.016±0.007L/min、0.010±0.004L/min/kg. The main phannacokinetic parameters of A、B、C、D four groups for Clindamycin Phosphate group respectively were as follows:Distribution half-life were18.33±0.46min、23.80±0.33min、25.97±0.47min、44.51±0.23min. Peak concentration were847.91±0.45mg/L、871.32±0.55mg/L885.61±0.73mg/L、898.35±0.64mg/L、Apparent volume of distribution were0.747±0.018L/kg、0.729±0.017L/kg、0.721±0.045L/kg0.701±0.055L/kg、Clearance rate were0.739±0.137L/min、0.028±0.08L/min、0.019±0.089L/min、0.012±0.164L/min.5-Fu standard and Clindamycin Phosphate standard had good peaks, retention time of5-Fu was (7.20±0.25)min, and that of inner standard was (15.52±0.50)min; the retention time of Clindamycin Phosphate was (14.82±0.25)min, and that of inner standard was (4.52±0.50)min. In the drug concentration-time curves, we figured out the metabolic speed sequence (from fast to slow) was infrahepatic inferior vena cava combined semi-liver blood flow blocking group--semi-liver blood flow blocking group--Pringle blocking group, except non blocking group.The linear regression equation of As/Ai vs sample concentration C was calculated, we obtained the standard curve equation Y=76.8386894806X-0.3980725458(As/Ai),(r=0.9997383631,n=6), the result shows that there was a good linear relationship in a range of1-100μg·mL-1. The quantitative limits of5-Fu was0.5μg·mL-1under the experimental condition; In group2, Standard curve equation was calculated as same as above, we obtained the standard curve equation Y=0.2483263225+64.3356372721X (As/Ai),(r=0.9984335256, n=6), the result showed that there was a good linear relationship in a range cf1-100μg·mL-1. The quantitative limits of5-Fu is0.625μg·mL-1under the experimental condition.The blood sample relative recovery rate:In group1, we added5-Fu standard solution into blank blood samples to get100,50,25,10,5,1μg·ml-1blood standard solution, carried out according to the blood sample procession, took20μL for testing.6concentration, each for3times, then calculated recovery rate, the result showed that the average recovery rate of5-Fu was109%, RSD was less than10%. In group2, we carried out as same as above, the average recovery rate of Clindamycin Phosphate was98.9%, RSD was less than5%.Conclusion:Results indicated that there were no differences in the best pharmacokinetic model among these four groups after intravenous injection of5-Fu and Clindamycin Phosphate, but the main pharmacokinetic parameters had significant differences. Acoording to the pharmacokinetic parameters of these groups of the two drugs, we summarized as follow:t1/2α from short to long:non-blocking group--infrahepatic inferior vena cava combined semi-liver blood flow blocking group--semi-liver blood flow blocking group--Pringle blocking group, the shorter the half time was, the faster the drug metabolized. After administered at the same dosage, Cmax of these four groups had significant differences(P<0.01), Cmax from high to low:Pringle blocking group--semi-liver blood flow blocking group--infrahepatic inferior vena cava combined semi-liver blood flow blocking group--non-blocking group. The lower the Cmax value was, the faster the drug absorption was. Vd value from big to small:non-blocking group--infrahepatic inferior vena cava combined semi-liver blood flow blocking group--emi-liver blood flow blocking group--Pringle blocking group, the bigger the Vd value was, the stronger the drug penetrability was. CL had certain differences, CL value from high to low:non-blocking group--infrahepatic inferior vena cava combined semi-liver blood flow blocking group--semi-liver blood flow blocking group--Pringle blocking group, the high the CL value was, the faster the drug cleaned, which meant the metabolic speed was fast. According to the two sets of drug concentration-time curves, we analyzed that:the metabolic speed sequence (from fast to slow) in rabbits was infrahepatic inferior vena cava combined semi-liver blood flow blocking group>semi-liver blood flow blocking group>Pringle blocking group. Based on the results, we suggested that the operator should adjust the dosage in hepatic blood flow blocking surgery, so as to avoid the adverse effect caused by drug accumulation.