Mousa S A, Olson R E, Bozarth J M, Lorelli W, Forsythe M S, Racanelli A, Gibbs S, Schlingman K, Bozarth T, Kapil R, Wityak J, Sielecki T M, Wexler R R, Thoolen M J, Slee A, Reilly T M, Anderson P S, Friedman P A
The DuPont Merck Pharmaceutical Co., Wilmington, Delaware 19880-0400, USA.
J Cardiovasc Pharmacol. 1998 Aug;32(2):169-76. doi: 10.1097/00005344-199808000-00001.
This study was undertaken to define the platelet glycoprotein alphaIIb beta3 integrin (GPII/IIIa) affinity, specificity, and oral antiplatelet efficacy of DMP 802, a small-molecule nonpeptide antiplatelet agent. Platelet GPIIb/IIIa integrin binding affinity and specificity for DMP 802 were determined by using binding and adhesion assays with cells from various species, including human. DMP 802 demonstrated a potent antiplatelet efficacy [median inhibitory concentration (IC50), 0.029 +/- 0.0042 microM] in inhibiting human platelet aggregation induced by 10 microM adenosine diphosphate (ADP), as assessed by light-transmittance aggregometry. DMP 802 inhibited 125I-fibrinogen binding to activated (ADP, epinephrine, and arachidonic acid at 100 microM each) gel purified human platelets with an IC50 of 0.012 +/- 0.003 microM. DMP 802 demonstrated tight association with unactivated human, baboon, or canine platelets (t(1/2) of dissociation, 32 +/- 2, 32 +/- 13, and 11 +/- 1 min, respectively). DMP 802 binds with high affinity to both unactivated and activated human platelets (Kd = 0.61 +/- 0.17, 0.57 +/- 0.21 nM, respectively). DMP 802 demonstrated species specificity in inhibiting platelet aggregation with IC50 values ranging from 0.025 to 0.092 microM (human, guinea pig, dog, swine, hamster) and 0.88-1.0 microM (rabbit and rat) in platelets obtained from these various species. DMP 802 demonstrated a high degree of specificity for platelet GPIIb/IIIa (alphaIIb/beta3) as compared with other integrins including alpha(v)beta3 (IC50, >10 microM), alpha(v)beta5 (IC50, >100 microM), alpha4beta1 (IC50, >100 microM), and alpha5beta1 (IC50, >10 microM). Oral antiplatelet efficacy of DMP 802 was examined after single oral (0.05-0.20 mg/kg) and after repeated oral dosing at 0.05 mg/kg daily for 5 days in mongrel dogs. Dose-dependent antiplatelet efficacy with an extended duration of antiplatelet efficacy was demonstrated based on ex vivo inhibition of platelet aggregation induced by 100 microM ADP. DMP 802 has an oral bioavailability of 14.9% in dogs. In conclusion, the alpha sulfonamide isoxazoline analog, DMP 802, is a novel oral antiplatelet agent with high affinity, relatively slow dissociation rate and specificity for human platelet GPIIb/IIIa receptors.
本研究旨在确定小分子非肽类抗血小板药物DMP 802的血小板糖蛋白αIIbβ3整合素（GPII/IIIa）亲和力、特异性及口服抗血小板疗效。通过对包括人类在内的各种物种的细胞进行结合和黏附试验，确定血小板GPIIb/IIIa整合素对DMP 802的结合亲和力和特异性。通过透光率聚集法评估，DMP 802在抑制10微摩尔二磷酸腺苷（ADP）诱导的人血小板聚集方面显示出强大的抗血小板疗效[半数抑制浓度（IC50），0.029±0.0042微摩尔]。DMP 802抑制125I-纤维蛋白原与活化的（分别为100微摩尔的ADP、肾上腺素和花生四烯酸）凝胶纯化人血小板的结合，IC50为0.012±0.003微摩尔。DMP 802与未活化的人、狒狒或犬血小板紧密结合（解离半衰期分别为32±2、32±13和11±1分钟）。DMP 802与未活化和活化的人血小板均具有高亲和力结合（解离常数分别为0.61±0.17、0.57±0.21纳摩尔）。DMP 802在抑制血小板聚集方面表现出物种特异性，在从这些不同物种获得的血小板中，IC50值范围为0.025至0.092微摩尔（人类、豚鼠、狗、猪、仓鼠）和0.88 - 1.0微摩尔（兔子和大鼠）。与其他整合素包括α(v)β3（IC50，>10微摩尔）、α(v)β5（IC50，>100微摩尔）、α4β1（IC50，>100微摩尔）和α5β1（IC50，>10微摩尔）相比，DMP 802对血小板GPIIb/IIIa（αIIb/β3）表现出高度特异性。在杂种犬中，单次口服（0.05 - 0.20毫克/千克）及每日0.05毫克/千克重复口服给药5天后，检测DMP 802的口服抗血小板疗效。基于对100微摩尔ADP诱导的血小板聚集的体外抑制，证明了剂量依赖性抗血小板疗效及抗血小板疗效的延长持续时间。DMP 802在犬中的口服生物利用度为14.9%。总之，α-磺酰胺异恶唑啉类似物DMP 802是一种新型口服抗血小板药物，对人血小板GPIIb/IIIa受体具有高亲和力、相对较慢的解离速率和特异性。
