Pactimibe sulfate (CS-505) is a dual ACAT1/2 inhibitor with IC50s of 4.9 μM and 3.0 μM, respectively. Pactimibe sulfate (CS-505) inhibits ACAT with IC50s of 2.0 μM, 2.7 μM, 4.7 μM in the liver, macrophages and THP-1 cells, respectively. Pactimibe sulfate (CS-505) noncompetitively inhibits oleoyl-CoA with a Ki value of 5.6 μM. Moreover, Pactimibe sulfate (CS-505) obviously inhibits cholesteryl ester formation with an IC50 of 6.7 μM. Pactimibe sulfate (CS-505) possesses anti-atherosclerotic potential with lowering plasma cholesterol activity[2].In Vitro: Pactimibe sulfate (CS-505) induces moderate ACAT inhibition in monocyte-derived macrophages, leading to the suppression of foam cell formation[2].In Vivo: Pactimibe sulfate (CS-505; 60 and 200 mg/kg/day; oral gavage; twice a day; 12 weeks) induces an inhibition for ACAT-1 and ACAT-2, causing a reduction of plasma cholesterol but no influence on macrophage- or collagen-positive areas.