Guanidine derivatives as combined thromboxane A2 receptor antagonists and synthase inhibitors.
A new series of omega-disubstituted alkenoic acid derivatives derived from samixogrel 5 were designed and synthesized as combined thromboxane A2 receptor antagonists/thromboxane A2 synthase inhibitors with improved solubility and reduced protein binding compared to 5. Hexenoic acid derivatives with a 3-pyridyl group and 3-(2-cyano-3-alkyl-guanidino)phenyl substituent were found to be optimal with regard to this dual mode of action. The most potent compound, E-6-(3-(2-cyano-3-tert-butyl-guanidino)phenyl)-6-(3-pyridyl)hex-5-eno ic acid, "terbogrel" 32 inhibits the thromboxane A2 synthase in human gel-filtered platelets with an IC50 value of 4.0 +/- 0.5 nM (n = 4). Radioligand binding studies with 3H-SQ 29,548 revealed that 32 blocks the thromboxane A2/endoperoxide receptor on washed human platelets with an IC50 of 11 +/- 6 nM (n = 2) and with an IC50 of 38 +/- 1 nM (n = 15) in platelet-rich plasma. Terbogrel inhibits the collagen-induced platelet aggregation in human platelet-rich plasma and whole blood with an IC50 of 310 +/- 18 nM (n = 8) and 52 +/- 20 nM (n = 6), respectively. This was shown to translate into a potent antithrombotic effect in vivo as demonstrated in studies using a model of arterial thrombosis in rabbits (ED50 = 0.19 +/- 0.07 mg/kg; n = 20). Thus, terbogrel is the first compound with a guanidino moiety demonstrating both a potent TXA2 synthase inhibition and a potent TXA2 receptor antagonism and has been selected for further clinical development.
Soyka
R
R
Research and Development, Boehringer Ingelheim Pharma KG, Birkendorfer Strasse 65, 88397 Biberach, Germany.
Guth
B D
BD
Weisenberger
H M
HM
Luger
P
P
Müller
T H
TH
D000818:Animals; D018360:Crystallography, X-Ray; D015195:Drug Design; D004791:Enzyme Inhibitors / Q000138:chemical synthesis* / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology; D005260:Female; D005343:Fibrinolytic Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology; D006146:Guanidines / Q000138:chemical synthesis* / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000138:chemical synthesis* / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology; D011725:Pyridines / Q000138:chemical synthesis* / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology; D011817:Rabbits; D011869:Radioligand Assay; D051381:Rats; D017482:Receptors, Thromboxane / Q000037:antagonists & inhibitors*; D013930:Thromboxane-A Synthase / Q000037:antagonists & inhibitors*
D004791:Enzyme Inhibitors; D005343:Fibrinolytic Agents; D006146:Guanidines; D010975:Platelet Aggregation Inhibitors; D011725:Pyridines; D017482:Receptors, Thromboxane; C112331:terbogrel; D013930:Thromboxane-A Synthase