Tazanolast

Tazanolast is an orally active selective mast cell stabilizer. Tazanolast prevents the elevation of intracellular calcium concentration, inhibits calcium uptake and Protein kinase C translocation, without directly inhibiting phospholipase C. Tazanolast inhibits ozone-induced airway hyperresponsiveness to Methacholine in guinea pigs, as well as passive cutaneous anaphylaxis, Schultz-Dale reaction, experimental asthma, passive cutaneous anaphylaxis in rats, and increased cutaneous vascular permeability in rats. Tazanolast does not alter airway responsiveness in sham-exposed guinea pigs, cell distribution in bronchoalveolar lavage fluid after ozone exposure, type II-IV allergic reactions, or histamine release from atopic leukocytes. Tazanolast can be used in research related to allergic diseases^[1][2]. In Vitro:Tazanolast acts as a selective mast cell stabilizer by inhibiting multiple mast cell activation pathways, including histamine release, calcium uptake, protein kinase C translocation, and inositol trisphosphate production, and suppresses the Schultz-Dale reaction in isolated tracheal muscle^[1].
Tazanolast prevents histamine release-inducing intracellular calcium concentration increases in mast cells^[3]. In Vivo:Tazanolast (30-300 mg/kg; p.o.; 30 minutes before ozone exposure) significantly inhibits ozone-induced airway hyperresponsiveness in guinea pigs in a dose-dependent manner when administered before ozone exposure, with the 300 mg/kg dose producing the greatest reduction in delta logPC₂₀₀-MCh to 0.09^[1].
Tazanolast (300 mg/kg; p.o.; 30 minutes before sham air exposure) does not affect baseline airway responsiveness or BAL cell distribution in healthy guinea pigs exposed to filtered air^[1].
Tazanolast (10 mg/kg; p.o.) significantly inhibits Ovalbumin (HY-W250978)-induced passive cutaneous anaphylaxis in rats and potently suppresses Substance P- and PGD₂-mediated increases in vascular permeability in rat skin^[2].