Flunixin Meglumine Injection

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

Flunixin Meglumine Injection is a sterile solution of Flunixin Meglumine in Water for Injection. It contains the equivalent of NLT 90.0% and NMT 110.0% of the labeled amount of flunixin (C₁₄H₁₁F₃N₂O₂). It may contain phenol or another suitable preservative.

2 IDENTIFICATION

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

B. THIN-LAYER CHROMATOGRAPHIC IDENTIFICATION TEST (201)

Buffer: Dissolve 4.1 g of anhydrous sodium acetate in 500 mL of water. Add 2.9 mL of glacial acetic acid, and dilute with water to 1000 mL.

Standard solution: 3 mg/mL of USP Flunixin Meglumine RS in methanol

Sample solution: Transfer the equivalent to 50 mg of flunixin from Injection to a 50-mL centrifuge tube. Add 10 mL of Buffer, and extract with 25 mL of ethyl acetate. Use the upper phase as the Sample solution.

Chromatographic system

Adsorbent: Silica gel

Application volume: 10 µL

Developing solvent system: Toluene, ethyl acetate, glacial acetic acid, and water (75:25:10:1)

Acceptance criteria: Meets the requirements

3 ASSAY

3.1 PROCEDURE

Mobile phase: Methanol, water, and acetic acid (70:30:1)

Diluent: Methanol and water (70:30)

System suitability solution: 0.33 mg/mL of USP Flunixin Meglumine RS and 0.02 mg/mL of phenol in Diluent

Standard solution: 0.33 mg/mL of USP Flunixin Meglumine RS

Sample solution: Transfer an amount of Injection equivalent to 500 mg of flunixin to a 250-mL volumetric flask, and dilute with Diluent to volume. Further dilute this solution with Diluent to obtain a solution containing 0.2 mg/mL of flunixin. Pass a portion of this solution through a filter of 0.45-µm or finer pore size, discarding the first few mL of the filtrate.

3.2 Chromatographic system

(See Chromatography (621), System Suitability.)

Mode: LC

Detector: UV 275 nm

Column: 4.6-mm × 15-cm; 5-µm packing L1

Column temperature: 30° ± 2°

Flow rate: 1 mL/min

Injection volume: 20 µL

3.3 System suitability

Sample: System suitability solution

Suitability requirements

Resolution: NLT 17 between phenol and flunixin meglumine

Tailing factor: NMT 2.0 for flunixin meglumine

Relative standard deviation: NMT 2.0%

3.4 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of flunixin (C₁₄H₁₁F₃N₂O₂) in the portion of Injection taken:

Result = (r_U/r_S) x (C_S/C_U) x (M_r1/M_r2) x 100

r_U = peak response from the Sample solution

r_S = peak response from the Standard solution

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

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

M_r1 = molecular weight of flunixin, 296.25

M_r2 = molecular weight of flunixin meglumine, 491.46

Acceptance criteria: 90.0%-110.0%

4 IMPURITIES

Change to read:

4.1 ORGANIC IMPURITIES

Mobile phase, Diluent, System suitability solution, Sample solution, and Chromatographic system: Proceed as directed in the Assay.

Sensitivity solution: 0.167 µg/mL of USP Flunixin Meglumine RS in Diluent (ERR 1-Mar-2020)

4.2 System suitability

Samples: System suitability solution and Sensitivity solution

Suitability requirements

Resolution: NLT 17 between phenol and flunixin meglumine, System suitability solution

Tailing factor: NMT 2.0, System suitability solution

Relative standard deviation: NMT 10.0%, Sensitivity solution

Signal-to-noise ratio: NLT 10, Sensitivity solution

4.3 Analysis

Samples: Sample solution and Sensitivity solution

Calculate the percentage of each impurity in the portion of Injection taken:

Result = (r_U/r_T) x 100

r_U = peak response of each individual impurity from the Sample solution

r_T = sum of all the peak responses from the Sample solution

Acceptance criteria: See Table 1. Disregard any peak less than the response of the flunixin meglumine peak as obtained from the Sensitivity solution (0.05%). Disregard the peak due to phenol, if present, which elutes at a relative retention time of 0.25 with respect to flunixin.

Table 1

5 SPECIFIC TESTS

5.1 BACTERIAL ENDOTOXINS TEST (85)

NMT 4.54 USP Endotoxin Units/mg of flunixin

5.2 STERILITY TESTS (71)

It meets the requirements when tested as directed in Test for Sterility of the Product to Be Examined, Membrane Filtration.

5.3 PH (791)

7.8-9.0

5.4 PARTICULATE MATTER IN INJECTIONS (788)

Meets requirements if labeled for IV use

6 ADDITIONAL REQUIREMENTS

6.1 PACKAGING AND STORAGE

Preserve in multiple-dose containers, and store between 2° and 30°.

6.2 LABELING

Label Injection to indicate that it is for veterinary use only.

6.3 USP REFERENCE STANDARDS (11)

USP Flunixin Meglumine RS