| IntroductionScoparone (6.7 - dimethoxycoumarin) is the main coumarin derivatives from the traditional medicine called " yinchen". Many pharmacological experiments proved that Sco showed strong anti - asthma action. We confident that Sco can be developed into a very effective and promising Chinese medicine, which has both incidental and fundamental aspects for the treatment of asthma. Sco isolated from the flowers and buds of Artemisia Scoparia Waidst. et Kit in Shenyang was found that the purity exceeded 99 percent in our laboratory. In order to elucidate the clinical effects of the traditional Chinese medicine, it is important to investigate their pharmacokinetics. Previous report has been found about the pharmacokmetics of Sco in rats. This study was to determine the concentration of Sco in rabbit plasma and investigate the pharmacokinetics of Sco in rabbits to help establishing its drug administration schedule in clinic.Materials and Methods1. Drug and reagentsSco isolated from the flowers and buds of Artemisia Scoparia Waidst. et Kit in Shenyang was found that the purity exceeded 99 %. Methanol and acetonitril was HPLC grade. All other reagents were an-alytical grade.2. AnimalsWhite rabbits weighing about (2. 2 0. 2) kg(x s) were used in this study. (Laboratory Animal Center of China Medical Universi-ty)3. Instruments and HPLC conditionA Waters 510 LC pump equipped with a Waters 486 ultraviolet detector including a 2010 data processing unit was used. Samples were chromotographed with an analytical column of Nova - Pak Silica Gig(3.9mm 150mm ID, 5 m) at 40t. The mobile phase was ace-tonitril -water(20: 80 v/v)with a flow rate of 1.0ml min-1 . The column eluate was monitored by UV detector at 345 nm.4. Determination of blood sampleTo 0. 5ml of plasma, 4ml of chloroform was added and vortexed for 1min. The mixture was centrifuged at 3000r -min-1 for 10min at room temperature. The organic phase was blown to dry by N2 at 60 . The residue was reconstituted in 100 l methanol and 20 l. of the solution was injected into HPLC.5. Drug administration and preparation of blood sample Rabbits were anesthetized with 20% urethane. 0. 1% sodiumheparin and Sco(2. 0,3. 6mg -kg-1 ) was administered by auricular vein. Blood samples (1.0ml) were drawn from the carotid artery at 0.5, 1, 1.5, 3, 6, 12,20, 30, 60, 90 and 120min after administration of Sco. The blood samples were centrifuged at 3000 r min-1 for 10min. The plasma were immediately separated and stored at -20t until analysis.6. Data and statistical analysisThe concentrations were analyzed with a 3p97 program of the Chi-nese Pharmacological Society on a personal computer to determine the compartment models and the pharmacokinetic parameters.Results1. Identification of determination of Sco in plasma sample1.1 Calibration graphAdd known amounts of Sco to blank plasma in the final concentration at 0.2, 0.6 , 1.0, 2.0, 6.0and10.0 g -ml-1. These plasma samples were treated according to the above assay procedure. The calibration curve was constructed by using the peak height of the drug and the corresponding concentration. Satisfactory linearity was observed in the concentration range of 0.2 -10. 0 g -ml-1 of the drug. The regression equation was y = 1. 203 104 + 2. 228 104 ( r = 0. 999) ,in the equation ,y is the peak height, x is the concentration( g ml-1)of the drug in plasma and r is the coefficient of correlation. The limit of detection for Sco under these conditions was 0. 1 g ml-1.1. 2 Recoveries and precisionsAdd known amounts of Sco to blank plasma in the final concentration at 0.2, 1.0,6.0 g 'ml-1 . These plasma samples were treated according to the above assay procedure 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 recoveries of Sco was 94.21% - 107. 83% , within - day precisions and inter - day precisions were under 10.0% .1.3...
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