Common Pharmaceuticals and Permitted Unknown Masses
| Pharmaceutical | U.S. Pharmacopeia purity requirements |
| Acetaminophen (325-mg tablet) | Acetaminophen contains no less than 98.0% and no more than 101.0% C8H9NO2, calculated on an anhydrous basis, of which no more than 0.014% can be as chloride, 0.02% as sulfate, 0.001% as heavy metals, 0.005% as p-aminophenol, and 0.001% as p-chloroacetanilide. Therefore, there can be up to 6.5 mg of unknowns in a 325-mg tablet, of which 3.25 μg may be heavy metals. |
| Acetylsalicylic acid (aspirin, 325-mg tablet) | Aspirin contains no less than 99.5% and no more than 100.5% C9H8O4, calculated on a dried basis, of which no more than 0.014% can be as chloride, 0.04% as sulfate, 0.1% as free salicylic acid, and 10 μg as heavy metals per gram of aspirin. Therefore, there can be up to 1.6 mg of unknowns in a 325-mg tablet, of which 3.25 μg may be heavy metals. |
| Atenolol (50-mg tablet) | Atenolol contains no less than 98.0% and no more than 102.0% C14H22N2O3, calculated on a dried basis. No more than 0.25% of any individual chromatographic impurity is found, and the sum of all chromatographic impurities is no more than 0.5%. Therefore, there can be up to 0.25 mg of unknown chromatographic impurity per 50-mg tablet, and there can be up to 0.75 mg of nonchromatographic impurity. |
| Ascorbic acid (vitamin C, 500-mg tablet) | Ascorbic acid contains no less than 99.0% and no more than 100.5% C6H8O6, with no more than 0.002% heavy metals, or up to 10 μg per 500-mg tablet. |
| Rolaids (Chattem, Inc.) (CaCO3, 675 mg, and Mg(OH)2, 135 mg, in one tablet) | CaCO3 contains no less than 98.0% and no more than 100.5% CaCO3. Heavy metal limit is 0.002%, or 13.5 μg/tablet; lead limit is 3 ppm (2 μg/tablet); arsenic limit is 3 ppm (2 μg/tablet); and mercury limit is 0.5 μg/g (0.33 μg/tablet). Mg(OH)2 contains no less than 95.0% and no more than 100.5% Mg(OH)2. Heavy metal limit is 20 μg/g, or 2.7 μg/tablet, but lead is no more than 0.202 μg/tablet. |
| Ibuprofen (200-mg tablet) | Ibuprofen contains no less than 97.0% and no more than 103.0% C13H18O2, calculated on an anhydrous basis. Heavy metal limit is 0.002%, or 4 μg/tablet. |