Ferrous Sulfate Tablets
» Ferrous Sulfate Tablets contain not less than 95.0 percent and not more than 110.0 percent of the labeled amount of ferrous sulfate (FeSO4·7H2O).
note—An equivalent amount of Dried Ferrous Sulfate may be used in place of FeSO4·7H2O in preparing Ferrous Sulfate Tablets.
Packaging and storage— Preserve in tight containers.
Labeling— Label the Tablets in terms of ferrous sulfate (FeSO4·7H2O) and in terms of elemental iron.
Identification— Dissolve a quantity of powdered Tablets, equivalent to about 250 mg of ferrous sulfate, in sufficient water, acidified with hydrochloric acid, to make 25 mL of solution: the solution responds to the tests for Ferrous Salts 191 and for Sulfate 191.
Dissolution 711
Medium: 0.1 N hydrochloric acid; 900 mL.
Apparatus 2: 50 rpm.
Time: 45 minutes.
Procedure— Determine the amount of FeSO4·7H2O dissolved, employing atomic absorption spectrophotometry at a wavelength of about 248.3 nm on filtered portions of the solution under test, suitably diluted with Dissolution Medium if necessary, in comparison with a Standard solution having a known concentration of iron in the same medium.
Tolerances— Not less than 75% (Q) of the labeled amount of FeSO4·7H2O is dissolved in 45 minutes.
Uniformity of dosage units 905: meet the requirements.
Assay— Weigh and finely powder not fewer than 20 Tablets. Dissolve a portion of the powder, equivalent to about 500 mg of ferrous sulfate and accurately weighed, in a beaker containing a mixture of 20 mL of 2 N sulfuric acid and 80 mL of freshly boiled and cooled water. Filter the solution rapidly as soon as all soluble ingredients in the tablets are dissolved, and wash the container and the filter with small portions of a mixture of 20 mL of 2 N sulfuric acid and 80 mL of freshly boiled and cooled water. Add orthophenanthroline TS, and immediately titrate the combined filtrate and washings with 0.1 N ceric sulfate VS. Each mL of 0.1 N ceric sulfate is equivalent to 27.80 mg of ferrous sulfate (FeSO4·7H2O).
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Topic/Question Contact Expert Committee
Monograph Curtis Phinney

(DSN05) Dietary Supplements - Non-Botanicals
711 Margareth R.C. Marques, Ph.D.
Senior Scientist
(BPC05) Biopharmaceutics05
USP32–NF27 Page 2366