Dexamethasone Acetate Injectable Suspension

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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» 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.

1 USP REFERENCE STANDARDS (11)-

USP Dexamethasone Acetate RS

Change to read:

IDENTIFICATION, SPECTROSCOPIC IDENTIFICATION TESTS (197), Infrared Spectroscopy: 197M _{▲(CN 1-May-2020)} -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 TEST (85) -It contains not more than 21.7 USP Endotoxin Units per mg of dexamethasone acetate.

PH (791): between 5.0 and 7.5.

Other requirements-It meets the requirements under Injections and Implanted Drug Products (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: 29

               (392.47/434.51)(500C / V)(r_U/r_S)

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 r_U and r_S are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.