Study The Pharmacokinetics Of Levofloxacin In The Prostate And Blood By Microdialysis And The Cellular Uptake Characteristics Of RWPE-1

ObjectiveHigh performance liquid chromatography（HPLC）was established for determination of levofloxacin concentrations in microdialysate.Microdialysis was used to study the pharmacokinetics of levofloxacin in the prostate and jugular vein of Beagle dogs.HPLC was established for determination of levofloxacin concentrations in cells.Study the characteristics of drugs entering human normal prostate epithelial cells.And its linear range,precision,recovery and stability were investigated.MethodsHPLC was established for determination of levofloxacin concentrations.Column is Kromasil C18（150 mm×4.6 mm,5μm）,the mobile phase consisted of acetonitrile and10 mmol/L of potassium dihydrogen phosphate solution（15∶85）,with column temperature being 30℃,detection wavelength being 294 nm,and injection volume being 10μL.The relative recoveries of vascular microdialysis probes in vitro was measured by dialysis and reverse dialysis.The effects of drug concentration and flow rate on probe deliveries were investigated.The in vivo recoveries of the probe in the jugular vein and prostate was measured by reverse dialysis,and the stability of 12 h recovery in vivo were investigated.Pharmacokinetic studies in the jugular vein and prostate were performed at appropriate flow rates based on the results of in vivo and in vitro corrections.HPLC was established for determination of levofloxacin concentrations in cells.Investigate the characteristics of levofloxacin entering RWPE-1 under different time,concentration,temperature and presence of P-glycoprotein inhibitor.ResultsWhen the concentration of levofloxacin was 0.1～50.0μg/ml,linear relationship was good in the HPLC analysis,correlation coefficient（R²）being 0.997,and its specificity was good.The precision and accuracy of high-,medium-,low-concentration quality control samples,and lower limit of quantification all met the analysis requirements.In the in vitro relative recovery experiments,there was no statistical difference between the recovery and reverse recovery of the vascular microdialysis probes（P>0.05）.Drug concentrations did not affect in vitro recovery.The recovery decreased with the increase of flow rate.In vivo,the relative recovery of probes in the jugular vein and prostate does not change with concentration.The relative recoveries were stable during 12 h.The pharmacokinetic parameters in blood and prostate are t_1/2（4.74±1.31）and（3.75±2.64）h,C_max（24.86±3.31）and（15.48±1.56）μg/ml,T_max（0.61±0.40）and（1.06±0.96）h,AUC_0-t为（80.55±28.12）and（50.97±6.74）μg·h·ml^-1,AUC_0-∞（115.82±41.20）and（67.77±23.16）μg·h·ml^-1,MRT（6.61±1.49）and（5.48±3.15）h,respectively.The analytical method of levofloxacin in cells was in the range of 0.05～5.0μg/ml,and the regression curve equation was:Y=53132X-556.13,R²=1.Precision,recovery and stability all met requirements.Levofloxacin concentration in the range of 4～160μg/ml,the intake began to increase,and then became saturated.At 37℃and 4℃,the average cell intake in the former condition was higher than that in the latter.The drug intake of the P-glycoprotein inhibitor experimental group and the blank control group was not statistically significant（P>0.05）,but the average intake of the former was higher than the latter.ConclusionThe established HPLC can be used for the determination of levofloxacin microdialysis probe,.Reverse dialysis can be used to detect the relative recovery of levofloxacin microdialysis probe in vivo.In vivo correction and pharmacokinetic flow rate was 1.5μl/min.The imbalance in the distribution of levofloxacin in the blood and the prostate may be due to the efflux of MRP4 protein present in prostate tissue.The established HPLC can be used for the determination of levofloxacin in cells.The uptake time of the cells was 15 min.P-glycoprotein may participate in the uptake of levofloxacin in RWPE-1 cells.