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A Potent and Selective Antagonist of Endothelin A Receptor

Cat #: S-186
Alternative Name TBC-11251
Lyophilized Powder yes
  • Bioassay Tested
  • Source Synthetic
    MW: 454.9
    Purity: >99% (HPLC)
    Effective concentration 1-100 nM.
    Chemical name N-(4-chloro-3-methyl-1,2-oxazol-5-yl)-2-[2-(6-methyl-1,3-benzodioxol-5-yl)acetyl]thiophene-3-sulfonamide.
    Molecular formula C18H15ClN2O6S2.
    CAS No.: 184036-34-8
    PubChem CID 216235
    Activity Sitaxsentan is a potent and selective antagonist of ET-A Endothelin receptors, inhibiting Endothelin-1 radioligand binding to human ET-A and ET-B receptors with IC50 of 1.4 nM and 9.8 µM, respectively (a 7000-fold selectivity). in vitro, Sitaxsentan inhibits Endothelin-1 induced phosphoinositide turnover with a pAof 8.01. Sitaxsentan is orally bioavailable and active in vivo1,2.
    1. Wu, C. et al. (1997) J. Med. Chem. 40, 1690.
    2. Langleben, D. et al. (2004) Chest 126, 1377.
    Shipping and storage Shipped at room temperature. Product as supplied can be stored intact at room temperature for several weeks. For longer periods, it should be stored at -20°C.
    Solubility Soluble in DMSO. Centrifuge all products before use (10000 x g 5 min).
    Storage of solutions Up to three months at -20°C.
    Our bioassay
    • Alomone Labs Sitaxsentan inhibits ET-A receptor-mediated Ca2+ mobilization in CHO cells.
      Alomone Labs Sitaxsentan inhibits ET-A receptor-mediated Ca2+ mobilization in CHO cells.
      Dose response plot of Sitaxsentan (#S-186) inhibition of the ET-A receptor-mediated, Endothelin-1-evoked Ca2+ mobilization. IC50 was determined at 11.67 nM. Cells were loaded with Calcium 6 dye, incubated with Sitaxsentan, and stimulated with 15 nM Endothelin-1 (EC80). Changes in intracellular Ca2+ levels were detected as changes in maximum relative fluorescence (RLU) using FLIPRTETRA™.
    References - Scientific background
    1. Wu, C. et al. (1997) J. Med. Chem. 40, 1690.
    2. Lepist, E.I. et al. (2014) PLoS One 9, e87548.
    3. Saeki, T. et al. (1991) Biochem. Biophys. Res. Commun. 179, 286.
    Scientific background

    Sitaxsentan, is a synthetic compound that acts as a potent and selective antagonist of ET-A endothelin receptors. Sitaxsentan is one of the most selective ET-A antagonists reported1. Sitaxsentan inhibits Endothelin-1 radioligand binding to human ET-A and ET-B receptors with IC50 values of 1.4 nM and 9.8 µM, respectively1.

    In pulmonary arterial hypertension clinical trials, sitaxsentan was shown to improve exercise capacity, improve functional capacity, and delay clinical worsening. However, the compound shows high liver toxicity and is no longer used to treat hypertension2.

    Endothelin receptors include two subtypes: ET-A and ET-B. They are widely distributed in vascular and nonvascular tissues. ET-A receptors are predominantly detected in peripheral tissues, especially in vascular smooth muscle tissues to mediate vasoconstriction. They are also distributed in several regions of the brain.

    ET-A has high affinity for endothelin-1 and endothelin-2 and relatively low affinity for endothelin-3, while the ET-B receptor has high affinity equally for all endothelin isopeptides3.

    Target ET-A receptors
    Last update: 06/11/2022

    Sitaxsentan (#S-186) is a highly pure, synthetic, and biologically active compound.

    For research purposes only, not for human use
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