Packaging and storage—
Preserve in tight containers, and store at controlled room temperature.
Labeling—
Label it to indicate that it is to be well-shaken for 1 minute before use, and that it is not to be used if there are indications that the package has been exposed to freezing temperatures.
Microbial limits 
61
—
It meets the requirements of the tests for absence of
Escherichia coli. The total aerobic microbial count does not exceed 100 cfu per mL.
Magnetic susceptibility—
Apparatus, Standard solutions, Balance constant, and Tube constant—
Proceed as directed for
Magnetic susceptibility under
Ferumoxides Injection.
Procedure—
Proceed as directed for
Magnetic susceptibility under
Ferumoxides Injection except to use undiluted Oral Suspension whenever Injection is indicated. Calculate the magnetic susceptibility, in cgs units, per g of iron in the Oral Suspension by the formula:
1000CTR/I,
in which
CT is the
Tube constant; R is the balance reading, in cgs units; and
I is the concentration, in mg per g, of iron in the Oral Suspension, as determined in the
Assay for iron. The magnetic susceptibility is not less than 22,500 × 10
–6 in cgs units per g of iron.
Settling—
Prepare a mixture of Oral Suspension and water (1:5). Mix by gentle inversion, and determine the absorbance at 500 nm in a suitable spectrophotometer, using water as the blank. Cover the cell, and allow to stand undisturbed for 4 hours at room temperature. Without mixing, determine the absorbance again. Calculate the percentage of iron remaining in solution after settling by the formula:
100(A4 / A0),
in which
A4 is the absorbance of the solution after standing for 4 hours; and
A0 is the initial absorbance of the solution: not less than 80% is found.
Assay for iron—
Iron standard solution and Standard preparations—
Proceed as directed in the
Assay for iron under
Ferumoxides Injection.
Assay preparation—
Transfer about 5 g of well-mixed Oral Suspension, accurately weighed, to a 100-mL volumetric flask. Add 2 mL of nitric acid, and mix. Transfer the flask to a boiling water bath, and boil for 30 minutes to obtain a yellowish solution. Allow to cool to room temperature, dilute with water to volume, and mix.
Procedure—
Proceed as directed in the
Assay for iron under
Ferumoxides Injection. Calculate the iron concentrations, in µg per mL, of the three
Standard preparations by the formula:
20(AS / A20),
in which
AS is the absorbance of the relevant
Standard preparation; and
A20 is the absorbance of the
Standard preparation containing 20 µg per mL. The reading for each
Standard preparation, AS, is within 0.5 µg per mL of its nominal concentration. Measure the absorbance of the
Assay preparation, and calculate the content of iron, in µg per mL, in the Oral Suspension by the formula:
2000(AU / A20)(1.01/W),
in which
AU is the absorbance of the
Assay preparation; A20 is the absorbance as defined above; 1.01 is the specific gravity of the Oral Suspension; and
W is the weight, in g, of Oral Suspension taken to prepare the
Assay preparation.
Auxiliary Information—
Staff Liaison :
Andrzej Wilk, Ph.D., Senior Scientific Associate
Expert Committee : (RMI05) Radiopharmaceuticals and Medical Imaging Agents 05
USP29–NF24 Page 904
Pharmacopeial Forum : Volume No. 29(6) Page 1885
Phone Number : 1-301-816-8305
