AS-35

AS-35 is an orally effective, potent and selective antagonist of leukotrienes, antagonizes LTC4-, LTD4 and LTE4-induced contractions of the ileum with IC₅₀ values of 8 nM, 4 nM and 3 nM, respectively, and has antiallergic activities. In Vitro: In isolated guinea pig preparations, AS-35 antagonizes LTC4-, LTD4 and LTE4-induced contractions of the ileum with IC₅₀ values of 8 nM, 4 nM and 3 nM, respectively. In the trachea, the agent also antagonizes LTD4 and LTE4-induced con tractions with IC₅₀ values of 10 nM and 20 nM, respectively. However, AS-35 does not antagonize LTC4-induced tracheal contraction in the presence of L-serine borate^[1]. In Vivo: AS-35 (0.0375 to 0.3 mg/kg, i.v.) dose-dependently antagonizes bronchoconstriction induced by i.v.-injection of LTC4 and LTD4 in anesthetized guinea pigs, but does not inhibit histamine-induced bronchoconstriction. Oral administration of AS-35 also antagonizes LTD4 as well as antigen-induced LT-mediated bronchoconstriction. AS-35 (p.o.) inhibits LTD4-induced increase in the cutaneous vascular permeability of guinea pig^[1].