Dexamethasone Oral Solution

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 Oral Solution contains NLT 90.0% and NMT 110.0% of the labeled amount of dexamethasone (C₂₂H₂₉FO₅). 

2 IDENTIFICATION

A. The retention time of the dexamethasone peak from the Sample solution corresponds to that of the Standard solution, as obtained in the Assay.

3 ASSAY

3.1 PROCEDURE

Mobile phase: Methanol and water (1:1)

Internal standard solution: 0.1 mg/mL of USP Prednisolone RS in methanol

System suitability stock solution: 0.6 mg/ml. of USP Methylparaben RS and 0.075 mg/mL of USP Propylparaben RS in methanol

System suitability solution: 0.24 mg/mL of USP Methylparaben RS, 0.03 mg/mL of USP Propylparaben RS, and 0.01 mg/mL of USP Prednisolone RS prepared as follows. To an amount of System suitability stock solution equivalent to 40% of the final volume, add an amount of Internal standard solution equivalent to 10% of the final volume. Dilute with water to volume.

Standard stock solution: 0.2 mg/mL of USP Dexamethasone RS in Mobile phase

Standard solution: 0.02 mg/mL of USP Dexamethasone RS and 0.01 mg/mL of USP Prednisolone RS in Mobile phase prepared by diluting suitable volumes of Standard stock solution and Internal standard solution

Sample solution: Nominally equivalent to 0.02 mg/mL of dexamethasone from a volume of Oral Solution and 0.01 mg/mL of USP Prednisolone RS in Mobile phase from the Internal standard solution

3.1.1 Chromatographic system

(See Chromatography (621), System Suitability.)

Mode: LC

Detector: UV 254 nm

Column: 3.9-mm x 30-cm; packing L1

Flow rate: 1.4 mL/min

Injection volume: 10 µL

3.1.2 System suitability

[NOTE-The relative retention times for methylparaben, prednisolone, propylparaben, and dexamethasone are about 0.43, 0.71, 0.88, and 1.0, respectively.]

Samples: System suitability solution and Standard solution

3.1.3 Suitability requirements

Resolution: NLT 2.0 between methylparaben and prednisolone; NLT 2.0 between propylparaben and prednisolone, System suitability solution

Tailing factor: NMT 2.0 for each peak, System suitability solution and Standard solution

Relative standard deviation: NMT 2.0% for the peak height ratio of dexamethasone to prednisolone, Standard solution

3.1.4 Analysis

Samples: Standard solution and Sample solution

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

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

R_U = peak height ratio of dexamethasone to prednisolone from the Sample solution

R_S = Rpeak height ratio of dexamethasone to prednisolone 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%

4 OTHER COMPONENTS

ALCOHOL DETERMINATION, Method // (611) (if present): 27.0%-33.0%

5 PERFORMANCE TESTS

UNIFORMITY OF DOSAGE UNITS (905): Meets the requirements for oral solution packaged in single-unit containers

DELIVERABLE VOLUME (698): Meets the requirements for oral solution packaged in multiple-unit containers

6 SPECIFIC TESTS

PH (791): 2.7-4.0

7 ADDITIONAL REQUIREMENTS

PACKAGING AND STORAGE: Preserve in tight containers. Store at controlled room temperature.

LABELING: Label concentrated Oral Solution to state that the term "Concentrate" is to appear apart from and immediately after the official title in prominent boldface type. Label concentrated Oral Solution also to indicate that it is to be diluted to appropriate strength with a suitable diluent prior to administration unless produced for dispensing with instructions for administration by a calibrated dropper or syringe.

USP REFERENCE STANDARDS (11)

USP Dexamethasone RS

USP Methylparaben RS

USP Prednisolone RS

USP Propylparaben RS