DESCRIPTION
The active ingredient in NEXIUM (esomeprazole magnesium) Delayed-Release Capsules is bis( 5-methoxy-2-[( S)-[( 4-methoxy-3, 5-dimethyl-2-pyridinyl) methyl] sulfinyl]-1H-benzimidazole-1-yl) magnesium trihydrate, a compound that inhibits gastric acid secre-tion. Esomeprazole is the S-isomer of omeprazole, which is a mixture of the S-and R-isomers. Its empirical formula is (C17 H18N3O3S) 2 Mg x 3 H2O with molecular weight of 767.2 as a trihydrate and 713.1 on an anhydrous basis.
The magnesium salt is a white to slightly colored crystalline powder. It contains 3 moles of water of solvation and is slightly soluble in water. The stability of esomeprazole magnesium is a function of pH; it rapidly degrades in acidic media, but it has acceptable stability under alkaline conditions. At pH 6.8 (buffer), the half-life of the magnesium salt is about 19 hours at 25° C and about 8 hours at 37° C.
NEXIUM is supplied as Delayed-Release Capsules for oral administration. Each delayed-release capsule contains 20 mg or 40 mg of esomeprazole (present as 22.3 mg or 44.5 mg esomeprazole magne-sium trihydrate) in the form of enteric-coated pellets with the following inactive ingredients: glyceryl monostearate 40-50, hydroxy-propyl cellulose, hypromellose, magnesium stearate, methacrylic acid copolymer type C, polysorbate 80, sugar spheres, talc, and triethyl citrate. The capsule shells have the following inactive ingredients: gelatin, FD& C Blue #1, FD& C Red #40, D& C Red #28, titanium dioxide,
