U.S. PHARMACOPEIA

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Dexamethasone Acetate Injectable Suspension
» Dexamethasone Acetate Injectable Suspension is a sterile suspension of Dexamethasone Acetate in Water for Injection. It contains an amount of dexamethasone acetate monohydrate (C24H31FO6·H2O) equivalent to not less than 90.0 percent and not more than 110.0 percent of the labeled amount of dexamethasone (C22H29FO5).
Packaging and storage— Preserve in single-dose or multiple-dose containers, preferably of Type I glass.
Identification, Infrared Absorption 197M— Obtain the test specimen as follows. Transfer the contents of a well-shaken container of Injectable Suspension to a fine-porosity, sintered-glass vacuum filter, filter, and wash with several 10-mL portions of water. Remove the powder from the filter and allow to air-dry. [NOTE—Do not use heat to dry the specimen. Total or partial dehydration may occur. Use a similar undried preparation of USP Dexamethasone Acetate RS.]
Bacterial endotoxins 85— It contains not more than 21.7 USP Endotoxin Units per mg of dexamethasone acetate.
pH 791: between 5.0 and 7.5.
Residual solvents 467: meets the requirements.
(Official January 1, 2007)
Other requirements— It meets the requirements under Injections 1.
Assay—
Mobile phase, pH 6.0 Buffer solution, Diluent, and Chromatographic system— Proceed as directed in the Assay under Dexamethasone Acetate.
Standard preparation— Dissolve an accurately weighed quantity of USP Dexamethasone Acetate RS in Diluent to obtain a solution having a known concentration of about 0.09 mg per mL.
Assay preparation— Transfer an accurately measured volume of well-shaken Injectable Suspension, equivalent to about 40 mg of dexamethasone, to a 100-mL volumetric flask. Add 75 mL of Diluent, and sonicate until a clear solution is obtained. Dilute with Diluent to volume, and mix. Transfer 10.0 mL of this solution to a 50-mL volumetric flask, dilute with Diluent to volume, and mix.
Procedure— Separately inject equal volumes (about 20 µL) of the Standard preparation (before and after injections of the Assay preparation) and the Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity, in mg, of dexamethasone (C22H29FO5) in each mL of the Injectable Suspension taken by the formula:
(392.47 / 434.51)(500C / V)(rU / rS),
in which 392.47 and 434.51 are the molecular weights of dexamethasone and anhydrous dexamethasone acetate, respectively; C is the concentration, in mg per mL, of USP Dexamethasone Acetate RS in the Standard preparation; V is the volume, in mL, of Injectable Suspension taken; and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.
Auxiliary Information— Staff Liaison : Daniel K. Bempong, Ph.D., Scientist
Expert Committee : (MDPS05) Monograph Development-Pulmonary and Steroids
USP29–NF24 Page 648
Phone Number : 1-301-816-8143