Ferumoxsil Oral Suspension
»Ferumoxsil Oral Suspension is an aqueous suspension of silicone-coated superparamagnetic iron oxide.It contains not less than 90.0percent and not more than 110.0percent of the labeled amount of iron (Fe).It contains a preservative and a thickening agent.It may contain suitable colors,flavors,and sweetening agents.Ferumoxsil is poly[N-(2-aminoethyl)-3-aminopropyl]siloxane-coated nonstoichiometric magnetite [FeOX(C5H13N2SiO2)Y].
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 1minute before use,and that it is not to be used if there are indications that the package has been exposed to freezing temperatures.
Viscosity á911ñ: between 11and 60centipoises.
Osmolarity á785ñ: between 230and 270mOsmol per kg.
Microbial limits á61ñ— It meets the requirements of the tests for absence of Escherichia coli.The total aerobic microbial count does not exceed 100cfu per mL.
pHá791ñ: between 5.5and 9.0.
Magnetic susceptibility—
Apparatus,Standard solutions,Balance constant,and Tube constant— Proceed as directed for Magnetic susceptibilityunder Ferumoxides Injection.
Procedure— Proceed as directed for Magnetic susceptibilityunder Ferumoxides Injectionexcept 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 CTis the Tube constant;Ris the balance reading,in cgs units;and Iis 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 22,500×10–6in 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 500nm in a suitable spectrophotometer,using water as the blank.Cover the cell,and allow to stand undisturbed for 4hours 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 A4is the absorbance of the solution after standing for 4hours;and A0is the initial absorbance of the solution:not less than 80%is found.
Uniformity of dosage units á905ñ—
FOR ORAL SUSPENSION PACKAGED IN SINGLE-UNIT CONTAINERS: meets the requirements.
Deliverable volume á698ñ—
FOR ORAL SUSPENSION PACKAGED IN MULTIPLE-UNIT CONTAINERS: meets the requirements.
Assay for iron—
Iron standard solution andStandard preparations— Proceed as directed in the Assay for ironunder Ferumoxides Injection.
Assay preparation— Transfer about 5g of well-mixed Oral Suspension,accurately weighed,to a 100-mLvolumetric flask.Add 2mLof nitric acid,and mix.Transfer the flask to a boiling water bath,and boil for 30minutes 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 ironunder Ferumoxides Injection.Calculate the iron concentrations,in µg per mL,of the three Standard preparationsby the formula:
20(AS/A20),
in which ASis the absorbance of the relevant Standard preparation;and A20is the absorbance of the Standard preparationcontaining 20µg per mL.The reading for each Standard preparation,AS,is within 0.5µg per mLof 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 AUis the absorbance of the Assay preparation;A20is the absorbance as defined above;1.01is the specific gravity of the Oral Suspension;and Wis 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:(RMI)Radiopharmaceuticals and Medical Imaging Agents
USP28–NF23Page 824
Pharmacopeial Forum:Volume No.29(6)Page 1885
Phone Number:1-301-816-8305