Résumé
AIM:To study the effects and mechanisms of a novel sulfonylureous compound 1 ｛4 [2 (4 bromobenzenesulfonaminoethyl)phenylsufonyl｝ 3 (trans 4 methylcyclohexyl) urea, G004, on antithrombosis. METHODS: The influence of compound G004 on the vasoconstrictor action, platelet aggregation and thrombosis formation was studied. The effects of compound G004 on the tail vein bleeding time in mice was examined. The influence of compound G004 on the release of prostanglandin I 2 and thromboxan A 2 from ECV304 cells was investigated. The measurement of cytosolic free Ca 2+ in attached ECV304 cells loaded with Fluo3/AM was carried out. RESULTS: Compound G004 did not inhibit the contraction of rat aorta rings induced by norepinephrine or potassium chloride, but potently inhibit human platelet aggregation challenged by arachidonic acid and adenosine diphosphate. Compound G004 significantly prolonged the tail vein bleeding time in mice and occlusion time of carotid artery in experimentally thrombotic rats. Compound G004 reduced mice mortality induced by the collagen plus epinephrine in a dose dependent manner. Compound G004 enhanced PGI 2 release and reduced TXA 2 secretion from ECV304 cells. G004 had no effect on the increase of cytosolic free Ca 2+ induced by patassium chloride. CONCLUSION: The compound G004 has a remarkable antithrombotic effect in vivo. Its active mechanism may be attributed to inhibition of platelet aggregation, enhancing PGI 2 generation and decreasing TXA 2 secretion from human umbilical vein endothelium.
Résumé
Aim To establish an analytical method for determination of compound G004 concentration in plasma and investigate its application to pharmacokinetics and absolute bioavailability in rats.Methods 5.0 and 2.5 mg?kg~(-1) compound G004 were given via ig and iv respectively to SD rats.Blood samples were collected at various time points after administration.Plasma concentration of compound G004 in rats was determined by LC-ESI-MS.Pharmacokinetic parameters were calculated by DAS program and absolute bioavailability was also calculated.Results The method was linear over the range of 0.02～5 mg?L~(-1)(r~2=0.9995).The recovery of compound G004 in rat plasma was more then 87%.Intra-and inter-day precision,expressed as the relative standard deviation(RSD) was less than 15%.After iv compound G004,the main pharmacokinetic parameters T_(2),CLs,V_d,AUC_((0-∞)) were(1.91?0.65) h,(0.36?0.22) L?h~(-1),(0.78?0.36) L ?kg~(-1),(9.52?3.53) mg?L~(-1)?h~(-1) respectively.The major pharmacokinetic parameters T_(max),C_(max),T_(2),AUC_((0-∞)),MRT_((0-12h)) were 0.83 h,(3.33?0.80) mg?L~(-1),(1.77?0.21) h,(10.04?2.43) mg?L~(-1)?h~(-1) and(2.75?0.31)h after ig compound G004.The absolute bioavailability was 52.69% after correction of dosage.Conclusion The method is sensitive and specific which is applicable to pharmacokinetic analysis of compound G004 in rats.