[Anti-allergic activity of betotastine besilate (TAU-284), a new anti-allergic drug].

The anti-allergic activity of betotastine besilate (betotastine), a new anti-allergic drug, was investigated in several allergy models of rats in comparison with other anti-allergic drugs.1) Orally administered betotastine (0.1-30 mg/kg) inhibited homologous passive cutaneous anaphylaxis (PCA) in rats in a dose-dependent manner (ID30-value: 0.38 mg/kg). The inhibitory activity of betotastine was significant at 1 mg/kg and was more potent than that of ketotifen, terfenadine, cetirizine and epinastine. The PCA-inhibitory activity of betotastine lasted more than 8 hr after administration, and the repeated administration of betotastine lasted more than not induce drug-tolerance. 2) Orally administered betotastine inhibited the histamine-induced skin reaction in rats in a dose-dependent manner (ID30:0.10 mg/kg), and the inhibitory activity lasted more than 4 hr after the administration. Its inhibitory activity was significant at 0.1 and 1 mg/kg and was more potent than those of ketotifen, terfenadine, cetirizine and epinastine. 3) Betotastine suppressed histamine release from rat peritoneal mast cells at a high concentration (10(3)(10(-3)M). These results suggest that betotastine has a potent and long acting anti-allergic activity, and these effects are mainly due to histamine antagonistic activity.