Methylprednisolone 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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1 DEFINITION

Methylprednisolone Acetate Injectable Suspension is a sterile suspension of Methylprednisolone Acetate in a suitable aqueous medium. It contains NLT 90.0% and NMT 110.0% of the labeled amount of methylprednisolone acetate (C₂₄H₃₂O₆).

2 IDENTIFICATION

A. Spectroscopic Identification Tests 〈197〉, Infrared Spectroscopy: 197K

Sample: Nominally 100 mg of methylprednisolone acetate from Injectable Suspension

Analysis: Filter the Sample through paper. Wash the residue with several 5-mL portions of water, and dry at 105° for 3 h.

Acceptance criteria: Meets the requirements

3 ASSAY

Change to read:

Procedure

Mobile phase: n-Butyl chloride, water-saturated n-butyl chloride, tetrahydrofuran, methanol, and glacial acetic acid (95:95:14:7:6)

Internal standard solution: 6 mg/mL of ▲USP Prednisone RS▲ (IRA 1-Dec-2024) prepared as follows. Transfer an appropriate amount of ▲USP

Prednisone RS▲ (IRA 1-Dec-2024) to a suitable volumetric flask. Add 3% of the flask volume of glacial acetic acid, and sonicate. Dilute with

chloroform to volume, slowly adding the chloroform. Sonicate, and shake to dissolve.

Standard solution: 0.2 mg/mL of USP Methylprednisolone Acetate RS prepared as follows. Transfer an appropriate amount of USP

Methylprednisolone Acetate RS to a suitable volumetric flask, and add 5% of the flask volume of the Internal standard solution. Dilute with

chloroform to volume, and shake to dissolve.

Sample solution: ▲Nominally 0.188 mg/mL of methylprednisolone acetate from Injectable Suspension prepared as follows.▲ (IRA 1-Dec-2024)

Swirl Injectable Suspension to ensure uniformity before analysis. Transfer a suitable quantity of Injectable Suspension equivalent to 40 mg

of methylprednisolone acetate to a 25-mL volumetric flask, add 10.0 mL of the Internal standard solution, dilute with chloroform to volume,

and shake for 15 min or until the aqueous layer is clear. Transfer 4.0 mL of the chloroform layer to a suitable vial, add 30 mL of chloroform

and a small quantity (about 400 mg) of anhydrous sodium sulfate, and shake for 5 min. Use the clear solution.

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 254 nm

Column: 4-mm × 25-cm; packing L3

Flow rate: 1 mL/min

Injection volume: 10 µL

System suitability

Sample: Standard solution

[Note—The relative retention times for methylprednisolone acetate and prednisone are 1.0 and 1.3, respectively.]

Suitability requirements

Resolution: NLT 2.5 between methylprednisolone acetate and prednisone

Relative standard deviation: NMT 2.0% ▲for the peak height ratio of methylprednisolone and prednisone▲ (IRA 1-Dec-2024)

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of methylprednisolone acetate (C₂₄H₃₂O₆) in the portion of Injectable Suspension taken:

Result = (R₁ / R₂) × (C₁ / C₂) ▲× F▲ (IRA 1-Dec-2024) × 100

R₁ = peak height ratio of methylprednisolone acetate to prednisone from the Sample solution

R₂ = peak height ratio of methylprednisolone acetate to prednisone from the Standard solution

C₁ = concentration of USP Methylprednisolone Acetate RS in the Standard solution (mg/mL)

C₂ = nominal concentration of methylprednisolone acetate in the Sample solution (mg/mL)

▲F = correction factor for the Internal standard solution, 0.94▲ (IRA 1-Dec-2024)

Acceptance criteria: 90.0%–110.0%

4 PERFORMANCE TESTS

Uniformity of Dosage Units 〈905〉: Meets the requirements

5 SPECIFIC TESTS

pH 〈791〉: 3.0–7.0

Particle Size

Analysis: Transfer 1 drop to a microscope slide, and spread it evenly, diluting with water, if necessary, to decrease the density of the field.

Examine the slide under a microscope equipped with a calibrated ocular micrometer, using 400× magnification. Scan the entire slide, and

note the size of the individual particles.

Acceptance criteria: NLT 99% of the particles are less than 20 µm in length when measured along the longest axis, and NLT 75% of the

particles are less than 10 µm

Other Requirements: It meets the requirements in Injections and Implanted Drug Products 〈1〉.

6 ADDITIONAL REQUIREMENTS

Change to read:

Packaging and Storage: Preserve in single-dose or multiple-dose containers, preferably of Type I glass. ▲Store at controlled room temperature▲

(IRA 1-Dec-2024)

Change to read:

USP Reference Standards 〈11〉

USP Methylprednisolone Acetate RS

▲USP Prednisone RS▲ (IRA 1-Dec-2024)