Enrofloxacin Compounded Oral Suspension, Veterinary

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

Enrofloxacin Compounded Oral Suspension, Veterinary contains NLT 90.0% and NMT 110.0% of the labeled amount of enrofloxacin (C₁₉H₂₂FN₃O₃).

Prepare Enrofloxacin Compounded Oral Suspension, Veterinary 20 mg/ml, as follows (see Pharmaceutical Compounding-Nonsterile Preparations (795))

^aHumco, Texarkana, TX.

Prepare a hypromellose 1% solution by heating 25 mL of Purified Water to boiling in a calibrated beaker, and slowly adding 0.5 g of hypromellose with stirring. When the hypromellose is completely dispersed, take the beaker off heat, and add cold Purified Water with continuous stirring until gelled. Add cold Purified Water to bring to a final volume of 50 mL with stirring, Continue mixing until a clear, homogenous solution results. Place the solution in a refrigerator overnight to allow for complete hydration. Prepare the Vehicle by mixing equal volumes of the previously prepared hypromellose 1% solution and the Syrpalta.

Place the Enrofloxacin powder into a suitable mortar. Wet the powder with a small amount of Vehicle, and triturate to make a smooth paste. Add sufficient Vehicle to make the mortar contents pourable. Transfer the contents of the mortar, stepwise and quantitatively, to a calibrated container using the remainder of the Vehicle. Add sufficient Vehicle to bring to final volume. Shake to mix well.

2 ASSAY

PROCEDURE

Mobile phase: Acetonitrile and 50 mM phosphoric acid (15:85). Filter, and degas.

System suitability solution: Dissolve about 5 mg of USP Enrofloxacin Related Compound Mixture RS in a 10-ml volumetric flask, dilute with Mobile phase to volume, and mix.

Standard solution: 0.1 mg/ml, of enrofloxacin prepared from USP Enrofloxacin RS in Mobile phase

Sample solution: Shake thoroughly each bottle of Oral Suspension, Veterinary. Transfer 1 mL of Oral Suspension, Veterinary into a 200-ml volumetric flask, dilute with Mobile phase to volume, and mix well. Pass through a PVDF filter of 0.45-um pore size, discarding the first 3 mL

Chromatographic system

(See Chromatography (621), System Suitability)

Mode: LC

Detector: UV-Vis 277 nm

Column: 4.6-mm × 25-cm; 5-μm packing L1

Column temperature: 40°

Flow rate: 1.0 mL/min

Injection volume: 10 μL

System suitability

Samples: System suitability solution and Standard solution

[NOTE-The relative retention times for Ciprofloxacin and enrofloxacin are 0.76 and 1.0, respectively.]

Suitability requirements

Resolution: NLT 2.0 between enrofloxacin and ciprofloxacin, System suitability solution

Tailing factor: NMT 2.0, Standard solution

Relative standard deviation: NMT 2.0% for replicate injections, Standard solution

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of enrofloxacin (C₁₉H₂₂FN₃O₃) in the portion of Oral Suspension, Veterinary taken:

Result = (r_U/(r_S) × (C_S /C_U) x 100

r_U = peak response of enrofloxacin from the Sample solution

r_S = peak response of enrofloxacin from the Standard solution

C_S = concentration of USP Enrofloxacin RS in the Standard solution (mg/ml)

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

Acceptance criteria: 90.0%-110.0%

3 SPECIFIC TESTS

PH(791) :6.0-7.0

4 ADDITIONAL REQUIREMENTS

PACKAGING AND STORAGE: Package in tight, light-resistant containers. Store in a refrigerator (2°-8°) or at controlled room temperature.

BEYOND-USE DATE: NMT 90 days after the date on which it was compounded when stored in a refrigerator (2°-8°) or at controlled roam temperature

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