IBAT

S-8921 is an ileal Na ⁺ /bile acid cotransporter (IBAT) inhibitor. S-8921 inhibits the uptake velocity of 60 μM [ ³ H] taurocholate dose-dependently in IBAT-COS cells, and the IC ₅₀ value of S-8921 is 66±8 μM.

Seven-day treatment with S-8921 causes a dramatic decrease of serum cholesterol concentrations in hamsters. The hypocholesterolemic effects of S-8921 are dose-dependent, but S-8921 does not affect body weight. An increase of fecal bile acid excretion is observed especially at higher doses of S-8921. S-8921 treatment for 1 to 2 weeks causes a decrease in serum total cholesterol concentrations, with 0.01% S-8921 (4.0 to 4.6 mg/kg) being almost maximally effective.