| The aims of this study are to evaluate the pharmacokinetic profiles of Clevidipine butyrate injection in vivo, and to compare the pharmacokinetics between test preparation and the control preparation of butyrate Clevidipine injection in vivo. Clevidipine Butyrate is unstable in biological medium, because the ester bond of the molecule is rapidly hydrolyzed and converted into inactive product H 152/81, which is susceptible to oxidation, thus further producing more complex metabolites. Therefore, to accurately obtain the data of the parent drugs and the metabolites in vivo, we immediately terminated the enzyme-catalyzed hydrolytic reaction of biological samples, and stopped the oxidation reaction of metabolites H 152 /81 at the same time, thus solving the problem of sample stability in vitro. Using MRM mode which detects positive and negative ions at the same time, we established the LC / MS / MS method to measure Clevidipine and its major metabolite H 152 /81. The methodology verification indicates that this method meet the requirements of drug evaluation in specificity, linearity, precision, accuracy, recovery, matrix effects and stability.The content analysis of test and reference formulation indicates that there is no H152/81 detected in both formulation. Cevidipine butyrate content with no significant difference between formilations, is consistent with the labeled amount. Pharmacokinetic study of beagle dogs shows that during intravenous administration of two clevidipine butyrate injection(0.25 mg / 0.5 ml / 10 kg / min, for 40 min), blood clevidipine butyrate concentration rose rapidly and reached the plateau within 1.5- 2 min, suggesting that clevidipine butyrate has a short half-life elimination. After the i.v. drip, the concentration of butyrate in whole blood decreased rapidly. 10 min after the drip, the concentration was reduced to 10 n M, lower than detection limit after 4 h, and the elimination half life was 67- 93 min. The whole blood of clevidipine butyrate AUC(0-t) of test preparation and reference preparation was 11650 and 11640 n M·min respectively. The bioavailability of test preparation equals 102.3% of reference preparation. The statistical analysis indicates there is no significant difference between the two preparations(p=0.934).The metabolites H 152/81 concentration in the whole blood increased gradually intravenous drip and reached the peak till the end of infusion. The peak concentration is 2.0- 4.1 μ m, suggesting that butyrate clevidipine rapidly turns into H 152/81 during the infusion process. After the administration, whole blood H 152/81 concentration continued to decline, the end of the elimination half-life is 148- 198 min.The comparison of the drug concentration in artery and vein blood showed that test preparation arterial and venous blood clevidipine AUC(0-t) were 8073 and 6512 n M·min, while the reference preparation arteries and veins AUC(0-t) were 8978 and 6905 n M·min. This suggests that clevidipine butyrate artery exposure is slightly higher than the vein exposure. However, the statistical analysis shows that there was no significant difference between the arteries and veins, and no significant difference between two formulations.Moreover, the rat tissue distribution study showed that ratio of the test preparation AUC(0-t) / reference preparation AUC(0-t) was in the 90-115% range except for the intestinal contents. This results indicates that there was no significant difference in the tissue distribution of 152/81 H between two preparations.In conclusion, we found that the blood exposure and duration of parent drug and metabolite H 152 / 81 in two Clevidipine formulations are consistent. The arterial exposure volume of prototype drug of both formulations is slightly hitgher than the vein exposure. There is no significant difference in H 152 / 81. There is no significant difference in the tissue distribution of H 152 / 81 in rat. Our results suggest that the pharmacokinetics of test formulation and reference formulation in beagle dogs are not different, and the drug distribution in rat tissues is also consistent.This study aims to establish a stable and reliable method for quantitative analysis of the main component of skin active decontamination agent(RSDL), 2,3 butanedione oxim, measure plasma concentration- time curve after transdermal administration in rats, calculate plasma pharmacokinetic parameters and tissue distribution, and explore the role of RSDL in in vivo tracing and detoxification.GC-MS method was used in the present study instead of LC / MS / MS method which is much commonly used, because the quantitative detection of 2,3 butanedione oxime can be largely impacted by the baseline of LC / MS / MS with low sensitivity. The methodology verification indicates that this method followed by extraction with ethyl acetate, meets the requirements of drug evaluation in specificity, linearity, precision, accuracy and stability.Three doses(low: 0.1 ml, medium: 0.3 ml, high: 0.5 ml) of RSDL were adminsistrated to the rat skin, and the results showed that 2,3 butanedione oxime concentration quickly increased to reach a plateau after transdermal administration. Then the first peak occurred at about 30 min-1 h and the second peak occurs at about 300 min, followed by a slow decline. Then plasma concentration decreased to the undetectable level after 8 h, 12 h and 24 h, respectively.Plasma exposure of 2, 3-butanedione oxime increases with dose in a non-linear manner when doses greater than 0.3 ml / rat, suggesting the dynamics might be saturated. Because of individual vary of experimental animals, as well as the lack of accurate control of administration area, the absorb variability may increase. The second absorption peak may result from the reservoir effects of fat and muscle. The results from the distribution studies showed the 2,3 butanedione oxime mainly accumulated in fat, muscle and small intestine content, after transdermal administration of medium dose of RSDL in SD rats.Our results suggest that 2,3- butanedione oxime can be absorbed through the skin and distributed in different tissues at various levels. Given the 2,3- butanedione oxime detoxification activity in vitro, it is reasonable to assume that 2,3- butanedione oxime can not only react with the rest toxins at the skin surface patient’s skin, but is also able to penetrate the skin into the body and continue to play a role in detoxification.The experiments showed that 2,3- butanedione oxime, the main ingredient of RSDL canbe absorbed percutaneously, further detoxification in vivo might happen due to detoxification activity in vitro. In addition, the absolute bioavailability and the relative bioavailability compared to the original drugs on the market are needed to be considered. |
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