SPL Set ID: 540b6f6a-79f3-4681-8c2a-268cf7cecbc9

Bosentan, an endothelin receptor antagonist that belongs to a class of highly substituted pyrimidine derivatives, with no chiral centers. It is designated chemically as 4-tert-butyl-N-[6-(2-hydroxy-ethoxy)-5-(2-methoxy-phenoxy)-[2,2´]bipyrimidin-4-yl]- benzenesulfonamide monohydrate and has the following structural formula: Bosentan has a molecular weight of 569.63 and a molecular formula of C 27 H 29 N 5 O 6 S•H 2 O. Bosentan is a white to yellowish powder. It is poorly soluble in water (1.0 mg/100 mL) and in aqueous solutions at low pH (0.1 mg/100 mL at pH 1.1 and 4.0; 0.2 mg/100 mL at pH 5.0). Solubility increases at higher pH values (43 mg/100 mL at pH 7.5). In the solid state, bosentan is very stable, is not hygroscopic and is not light sensitive. Bosentan is available as a 32 mg tablet for oral suspension and contains the following excipients: microcrystalline cellulose, dibasic calcium phosphate, croscarmellose sodium, colloidal silicon dioxide, tutti fruitti flavor, aspartame, acesulfame potassium and magnesium stearate. Each dispersible tablet contains 1.85 mg of phenylalanine. Each dispersible tablet contains 33.045 mg of bosentan monohydrate, equivalent to 32 mg anhydrous bosentan. chemical-structure