Urea Compounded Irrigation

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

Urea Compounded Irrigation contains NLT 90.0% and NMT 110.0% of the labeled amount of urea (CH₄N₂O).

Prepare Urea Compounded Irrigation 200 mg/mL (20%) as follows (see Pharmaceutical Compounding—Sterile Preparations 〈797〉).

Dissolve the Urea in Sodium Chloride Irrigation. Pass through a sterilizing lter of 0.22-µm pore size into a sterile single-dose plastic bottle. [Note—Sterilize through ltration. Urea is not heat stable.]

2 ASSAY

Procedure

Mobile phase: Water

Standard solution: 0.5 mg/mL of USP Urea RS in water

Sample solution: Transfer 0.25 mL of Irrigation into a 100-mL volumetric ask, and add water to volume.

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 192 nm

Column: 4.6-mm × 25-cm; 5-µm packing L96

Temperatures

Autosampler: 4°

Column: 25°

Flow rate: 1.0 mL/min

Injection volume: 8 µL

System suitability

Sample: Standard solution

[Note—The retention time for urea is about 3.3 min.]

Suitability requirements

Tailing factor: NMT 2.0

Relative standard deviation: NMT 2.0% for replicate injections

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of urea (CH₄N₂O) in the portion of Irrigation taken:

Result = (r_u /r_s ) × (C_s /C_u ) × 100

r_u = peak response of urea from the Sample solution

r_s = peak response of urea from the Standard solution

C_s = concentration of USP Urea RS in the Standard solution (mg/mL)

C_u = nominal concentration of urea in the Sample solution (mg/mL)

Acceptance criteria: 90.0%–110.0%

3 SPECIFIC TESTS

pH 〈791〉: 6.5–9.0

Sterility Tests 〈71〉, Test for Sterility of the Product to Be Examined, Membrane Filtration: It meets the requirements.

Bacterial Endotoxins Test 〈85〉: NMT 0.003 USP Endotoxin Units/mg

4 ADDITIONAL REQUIREMENTS

Packaging and Storage: Package in sterile, single-dose plastic bottles. Store at controlled room temperature or in a refrigerator.

Change to read:

Beyond-Use Date: In the absence of performing and completing a sterility and endotoxin test, the storage conditions in Pharmaceutical

Compounding – Sterile Preparations 〈797〉, 14.3 Establishing a BUD for a CSP apply. _{(CN 1-Nov-2023)} When sterility and endotoxin results are within acceptable limits, NMT 60 days after the date on which it was compounded when stored at controlled room temperature or in a refrigerator.

Labeling: Label it to state the Beyond-Use Date.

USP Reference Standards 〈11〉

USP Urea RS