SPL Set ID: cdb2c4b4-a20a-3f8f-e053-2a95a90aaf72

The active ingredient in ondansetron tablets is ondansetron hydrochloride as the dihydrate, the racemic form of ondansetron and a selective blocking agent of the serotonin 5-HT3 receptor type. Chemically it is (±) 1, 2, 3, 9-tetrahydro-9-methyl-3-[(2-methyl-1H-imidazol-1-yl)methyl]-4H-carbazol-4-one, monohydrochloride, dihydrate. It has the following structural formula: The molecular formula is C18H19N3O•HCl•2H2O, representing a molecular weight of 365.86. Ondansetron HCl dihydrate USP is a white to off-white powder that is soluble in methanol, sparingly soluble in purified water and in alcohol, and slightly soluble in isopropyl alcohol, in dichloromethane, very slightly soluble in acetone, in chloroform and in ethyl acetate. Each 4 mg ondansetron tablets USP for oral administration contains ondansetron HCl dihydrate USP equivalent to 4 mg of ondansetron. Each 8 mg ondansetron tablets USP for oral administration contains ondansetron HCl dihydrate USP equivalent to 8 mg of ondansetron. Each 16 mg ondansetron tablets USP for oral administration contains ondansetron HCl dihydrate USP equivalent to 16 mg of ondansetron. Each 24 mg ondansetron tablets USP for oral administration contains ondansetron HCl dihydrate USP equivalent to 24 mg of ondansetron. Each tablet also contains the inactive ingredients colloidal silicon dioxide, hypromellose 2910(5cP) (for the 4 mg and 16 mg tablets only) and hypromellose 2910 (6cP) (for the 8 mg and 24 mg tablets only), iron oxide red and iron oxide black (for the 24 mg tablet only), iron oxide yellow (for the 8 mg and 24 mg tablets only), lactose monohydrate, magnesium stearate, microcrystalline cellulose, polyethylene glycol, pregelatinized starch, sodium starch glycolate, and titanium dioxide. STRUCTURE