Dexamethasone Compounded Oral 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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1 DEFINITION

Dexamethasone Compounded Oral Suspension contains NLT 90.0% and NMT 110.0% of the labeled amount of dexamethasone (C₂₂H₂₉FO₅). Prepare Dexamethasone Compounded Oral Suspension 1 mg/mL as follows (see Pharmaceutical Compounding-Nonsterile Preparations (795)).

^a Dexamethasone 4-mg tablets, Pharmascience Inc., Montréal, Quebec.

^b Medisca Pharmaceutique Inc., Montréal, Quebec.

Place the tablets in a suitable container and triturate to a fine powder. Add the Vehicle in small portions, and triturate to make a smooth paste. Add increasing volumes of the Vehicle to make a liquid that is pourable. Transfer the contents of the container, stepwise and quantitatively, to a calibrated bottle. Add a sufficient amount of Vehicle to bring to final volume, and mix well.

2 ASSAY

2.1 PROCEDURE

Solution A: 10 mM solution of ammonium formate adjusted with formic acid to a pH of 4

Solution B: Methanol, acetonitrile, and water (30:15:55)

Mobile phase: Methanol and Solution A (76:24)

Internal standard solution: 0.20 mg/mL of USP Naproxen RS in methanol

Standard solution: Transfer 10 mg of USP Dexamethasone RS to a 100-mL volumetric flask, add 10 mL of the Internal standard solution, and then dilute with Solution B to volume to obtain a solution containing 0.10 mg/mL of dexamethasone and 0.02 mg/mL of naproxen. Pass through a filter of 0.45-µm pore size.

Sample solution: Shake each bottle of Oral Suspension thoroughly. Transfer 10 mL of the Oral Suspension to a 100-mL volumetric flask, add 10 mL of the Internal standard solution, and dilute with methanol to volume. Mix well. Centrifuge at 5200 rpm for 5 min to obtain a solution containing 0.10 mg/mL of dexamethasone and 0.02 mg/mL of naproxen, and filter.

2.1.1 Chromatographic system

(See Chromatography (621), System Suitability.)

Mode: LC

Detector: UV 238 nm

2.1.2 Columns

Guard: 3,9-mm × 2-cm; 5-µm packing L1

Analytical: 4.6-mm x 15-cm; 5-µm packing 11

Flow rate: 1.0 mL/min

Injection volume: 10 µL

2.1.3 System suitability

Sample: Standard solution

[NOTE-The retention times for dexamethasone and naproxen are about 3.48 and 4.01 min, respectively.]

2.1.4 Suitability requirements

Tailing factor: NMT 2.0

Relative standard deviation: NMT 2.0% for replicate injections

2.1.5 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of dexamethasone (C₂₂H₂₉FO₅) in the portion of Oral Suspension taken: 

                Result = (R_U/R_S) x (C_S/C_U) × 100

R_U = peak response ratio of dexamethasone to the internal standard from the Sample solution

R_S = peak response ratio of dexamethasone to the internal standard from the Standard solution

C_S = concentration of USP Dexamethasone RS in the Standard solution (mg/mL)

C_U = nominal concentration of dexamethasone in the Sample solution (mg/mL)

Acceptance criteria: 90.0%-110.0%

3 SPECIFIC TESTS

PH (791): 4.0-5.0

4 ADDITIONAL REQUIREMENTS

PACKAGING AND STORAGE: Package in tight, light-resistant containers. Store at controlled room temperature or in a refrigerator.

BEYOND-USE DATE: NMT 90 days after the date on which it was compounded when stored at controlled room temperature or in a refrigerator

LABELING: Label it to indicate that it is to be well shaken before use and to state the Beyond-Use Date.

USP REFERENCE STANDARDS (11)

USP Dexamethasone RS

USP Naproxen RSA _{▲(USP 1-Dec-2021)}