| ObjectiveThe concentrations of 5-fluorouracil in the blood of mice were detected by RP - HPLC, the effects of OK-432 on the pharmacokinetics of 5-fluorouracil were studied when the former was followed by the latter, which provided basis for clinic.Method1. Disposal and determination of blood samples200 l of plasma were injected in 1.0 ml EP blanket , 25 l of 200 g 'ml-1 internal solutions 5-bromouracil and 200 l of 10% perchloric were added. The mixture were vortexed for 1 minute and then centriFuged at 10900 r min-1 for 5 min at room temperature. The supernatant was filtrated by filter membrane with 0.45 m micropore. 10 l of the filtrated solution was injected into HPLC.2. Administration of drug and collection of blood samples 5-fluorouracil of 75. 8 mg kg-1 (the concentration is 7.58 mg ml-1,0.2 ml/20 g) was injected into the abdominal cavity of mice in 5-fluoroural group. Blood samples were collected in heparinized cen-triFuge tube before and 1, 3 , 5, 10, 20, 30, 60, 90 and 120 minutes after the injection of 5-fluorouracil. All blood samples were centri-fuged for 15 minutes at 3000 r min-1. 200 l of supernatant was immediately added in EP blanket and stored in - 20 . OK-432 of 25KE kg -1 ( concentration is 2.5KE -ml-1 ,0.2 ml/20g)was injected into the abdominal cavity of mice in another group, the mice was given 5-fluorouracil after 30 minute of injection of OK-432 on the thirdday. The time and method of samplings were the same as mentioned a-bove.3. Statistical analysisThe results were analyzed with the 3p97 program designed by the Chinese Pharmacological Society to determine the compartment models and the pharmacokinetics parameters.Results1. Identification of determination of 5 -fluorouracil in plasma1. 1 Chromatograms of 5-fluorouracil and the specificityThe retention time of 5-fluorouracil is about 4. 0 min and retention time of internal standard is about 7. 1 min. Plasma endogenous materials dont interfere with the content of 5-fluorouracil.1.2 Standard curve5-Fu of various known concentration was added to plasma at the final concentration of 100, 50, 25, 10, 1 and 0. 1 g ml-1. They were processed according to the above procedure. The linear regression was constructed by using peak area comparison of the 5-Fu and 5-Bru and corresponding concentration. Satisfactory linearity was observed in the range of 0.1 - 100 g ml-1 of the drug. The regression equation was Y =0.0591C -0. 0040 ( r =0. 9993) , in the equation , Y is the peak area comparison , C is the concentration ( g ml -1) of the drug in plasma and r is the coefficient of correlation . The limit of detection for 5-Fu under these conditions was 0. 01 g ml-1.1. 3 Recoveries and precisionKnown amounts of 5-Fu were added to plasma at the final concentration of 50 , 25 and 0.1 g ml-1 . These samples were treated ac-cording to the above inter - day and within day repeatedly. The recovery of the compound was calculated by comparing the experimental value with the corresponding theoretical value. The mean relative recovery of 5-Fu was 93. 99 ~ 103.26% , the coefficients of variation of within - day and inter - day were both under 10%. 2. Study on Pharmacokinetic2.1 Concentration of 5-Fu in blood after igThe samples were treated and the corresponding concentrations in blood were calculated. The level of the drug declined with time in the two - compartment pattern.2.2 Pharmacokinetic parametersThe concentrations of 5-Fu and the corresponding times were processed by program 3p97. The present study showed that the absorption and maximum concentration of 5-Fu decreased, the half-life and the area under the curve increased. The elimination of 5-Fu in body slowed.ConclusionThe area below the curve of 5-Fu increased when OK -432 was used in combination, the totail amount of drug in circulation increased, the half life of elimination increased, the action time was prolonged. The dosage and interval of administration should be paid more... |
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