A novel class of orally active non-peptide bradykinin B2 receptor antagonists. 2. Overcoming the species difference between guinea pig and man.
Recently we reported the identification of a series of 8-[[3-(N-acylglycyl-N-methylamino)-2, 6-dichlorobenzyl]oxy]-3-halo-2-methylimidazo[1,2-a]pyridines as the first orally active non-peptide bradykinin (BK) B2 receptor antagonists (1-3). These compounds inhibited the specific binding of [3H]BK to guinea pig ileum membrane preparations expressing B2 receptors with nanomolar IC50's and also displayed in vivo functional antagonistic activities against BK-induced bronchoconstriction in guinea pigs at 1 mg/kg by oral administration. However, it was found that their affinities for the B2 receptors in human A-431 cells (human epidermoid carcinoma) were much lower. Intensive modifications of the terminal substituents at the glycine moiety elucidated the structure-activity relationships (SAR) for human B2 receptors, leading to an extended basic framework which incorporated a novel key pharmacophore. Thus, we overcame the species difference and identified the first clinical candidate 18c (FR167344) with IC50's of 0.66 and 1.4 nM for guinea pig ileum and human A-431 cells, respectively. This compound displayed in vivo functional antagonistic activity against BK-induced bronchoconstriction in guinea pigs with an ED50 value of 0.17 mg/kg by oral administration. This novel non-peptide B2 antagonist is extremely potent both in vitro and in vivo by oral administration and is expected to be the first member of a new class of drug for the treatment of various inflammatory diseases.
Abe
Y
Y
Exploratory Research Laboratories, Fujisawa Pharmaceutical Company, Ltd., 5-2-3, Tokodai, Tsukuba, Ibaraki 300-2698, Japan.
Kayakiri
H
H
Satoh
S
S
Inoue
T
T
Sawada
Y
Y
Inamura
N
N
Asano
M
M
Hatori
C
C
Sawai
H
H
Oku
T
T
Tanaka
H
H
D000284:Administration, Oral; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D065168:Bradykinin Receptor Antagonists; D016084:Bronchoconstriction / Q000187:drug effects; D002460:Cell Line; D004353:Drug Evaluation, Preclinical; D006168:Guinea Pigs; D006801:Humans; D007082:Ileum / Q000187:drug effects / Q000378:metabolism; D008297:Male; D011725:Pyridines / Q000008:administration & dosage / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D043782:Receptor, Bradykinin B2; D018002:Receptors, Bradykinin / Q000378:metabolism; D013045:Species Specificity; D013329:Structure-Activity Relationship
D000894:Anti-Inflammatory Agents, Non-Steroidal; D065168:Bradykinin Receptor Antagonists; C106745:FR 167344; D011725:Pyridines; D043782:Receptor, Bradykinin B2; D018002:Receptors, Bradykinin