Ferrous Fumarate Tablets

This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition

Issued and maintained by the United States Pharmacopeial Convention (USP)

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1 DEFINITION

Ferrous Fumarate Tablets contain NLT 95.0% and NMT 110.0% of the labeled amount of ferrous fumarate (C₄H₂FeO₄).

IDENTIFICATION

A. Identification Tests—General 〈191〉, Iron

Sample solution: To a portion of powdered Tablets, equivalent to 1 g of ferrous fumarate, add 25 mL of dilute hydrochloric acid (1 in 2), mix, and add 25 mL of water. Boil the solution for a few min, cool, and filter.

Acceptance criteria: The filtrate meets the requirements.

2 ASSAY

Procedure

Sample: A portion of the powder from NLT 20 finely powdered Tablets, equivalent to 500 mg of ferrous fumarate

Blank: Proceed as in the Analysis without the Sample.

Titrimetric system

(See Titrimetry 〈541〉.)

Mode: Indirect titration

Titrant: 0.1 N sodium thiosulfate VS

Indicator: Starch TS

Endpoint detection: Visual

Analysis: Transfer the Sample to a 250-mL beaker. Add 25 mL of water, 25 mL of nitric acid, and 7.5 mL of perchloric acid. Cover with a ribbed watch glass, and heat to the production of strong fumes. Cool, rinse the watch glass and the sides of the beaker with water, and evaporate in a hood to near-dryness. Wash down the watch glass and the sides of the beaker with 2 mL of hydrochloric acid and then with a small volume of water. Warm slightly, if necessary, to dissolve the residue. Transfer to a glass-stoppered, 250-mL conical ask. Repeat the washing with 2 mL of hydrochloric acid, and complete the transfer to the ask, using NMT 20–25 mL of water for the transfer. Add 4 g of potassium iodide to the ask, insert the stopper, and allow to stand in the dark for 5 min. Add 75 mL of water and titrate with Titrant, adding 3 mL of starch TS as the endpoint is approached. Perform a blank determination.

Calculate the percentage of the labeled amount of ferrous fumarate (C₄H₂FeO₄) in the portion of Tablets taken:

Result = {[(V_S − V_B ) × N_A × F]/W} × 100

V_S = Titrant volume consumed by the Sample (mL)

V_B = Titrant volume consumed by the Blank (mL)

N_A = actual normality of the Titrant (mEq/mL)

F = equivalency factor, 169.9 (mg/mEq)

W = nominal weight of ferrous fumarate in the Sample taken (mg)

Acceptance criteria: 95.0%–110.0%

3 PERFORMANCE TESTS

Change to read:

Dissolution 〈711〉

Medium: 0.1 N hydrochloric acid in 0.5% sodium lauryl sulfate; 900 mL

Apparatus 2: 75 rpm

Time: 45 min

[Note—Dissolution acceptance criteria may be met by using either of the Procedures below.]

Procedure 1 (USP 1-Dec-2021)

Standard solution: Solution having a known concentration of iron in the Medium

Sample solution: Filtered portion of the solution under test, suitably diluted with the Medium if necessary

Instrumental conditions

(See Atomic Absorption Spectroscopy 〈852〉.)

Mode: Atomic absorption spectrophotometry

Analytical wavelength: 248.3 nm

Lamp: Iron hollow-cathode

Flame: Air–acetylene

Analysis

Samples: Standard solution and Sample solution

Determine the concentration of iron (Fe) in the Sample solution in comparison with the Standard solution. Calculate the percentage of the labeled amount of ferrous fumarate (C₄H₂FeO₄) dissolved:

Result = (M_r /A_r ) × (C × D × V/L) × 100

M_r = molecular weight of ferrous fumarate, 169.9

A_r = atomic weight of iron, 55.85

C = measured concentration of iron in the Sample solution (mg/mL)

D = dilution factor for the Sample solution

V = volume of Medium, 900 (mL)

L = labeled amount of ferrous fumarate (mg/Tablet)

Procedure 2

Sample solution: Filtered portion of the solution under test, 100.0 mL

Blank: Medium, 100.0 mL Titrimetric system (See Titrimetry 〈541〉.) Mode: Direct titration

Titrant: 0.01 N ceric ammonium sulfate VS

Indicator: Ferroin TS

Endpoint detection: Visual

Analysis

Samples: Sample solution and Blank

Add 0.1 mL of Indicator to the Sample solution, and titrate with Titrant. Perform the same procedure for the Blank. Calculate the percentage of the labeled amount of ferrous fumarate (C₄H₂FeO₄) dissolved:

Result = [(V_S − V_B ) × N_A × F × V_M /V_SS ] × 100/L

V_S = Titrant volume consumed by the Sample solution (mL)

V_B = Titrant volume consumed by the Blank (mL)

N_A = actual normality of the Titrant (mEq/mL)

F = equivalency factor, 169.9 (mg/mEq)

V_M = volume of Medium, 900 (mL)

V_SS = volume of the Sample solution, 100.0 (mL)

L = labeled amount of ferrous fumarate (mg/Tablet) (USP 1-Dec-2021)

Tolerances: NLT 75% (Q) of the labeled amount of ferrous fumarate is dissolved.

Uniformity of Dosage Units 〈905〉: Meet the requirements

4 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in tight containers.

Labeling: Label the Tablets in terms of ferrous fumarate (C₄H₂FeO₄) and in terms of elemental iron.