Sodium Benzoate Compounded 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

Sodium Benzoate Compounded Oral Solution contains NLT 90.0% and NMT 110.0% of the labeled amount of sodium benzoate (C₇H₅NaO₂). Prepare Sodium Benzoate Compounded Oral Solution 100 mg/mL and 300 mg/mL as follows (see Pharmaceutical Compounding—Nonsterile Preparations 〈795〉).

Sodium Benzoate Compounded Oral Solution 100 mg/mL

Sodium Benzoate Compounded Oral Solution 300 mg/mL

In an appropriately size calibrated container, dissolve the Sodium Benzoate powder in about 80 mL of Purified Water. Stir until dissolved. Bring to final volume with Purified Water and mix well.

2 ASSAY

PROCEDURE

Solution A: 30 mM of potassium phosphate monobasic buffer adjusted with phosphoric acid to a pH of 3 Mobile phase: Methanol and Solution A (50:50)

Standard solution: 0.1 mg/mL of USP Sodium Benzoate RS in Mobile phase Sample solution

For Oral Solution 100 mg/mL: Transfer 1 mL of Oral Solution into a 100-mL volumetric flask, add approximately 80 mL of Mobile phase, and vortex. Dilute with Mobile phase to volume. Transfer 1 mL of this solution to a 10-mL volumetric flask, add approximately 8 mL of Mobile phase, and vortex. Dilute with Mobile phase to volume.

For Oral Solution 300 mg/mL: Transfer 1 mL of Oral Solution into a 100-mL volumetric flask, add approximately 80 mL of Mobile phase, and vortex. Dilute with Mobile phase to volume. Transfer 7 mL of this solution to a 200-mL volumetric flask, add approximately 150 mL of Mobile phase, and vortex. Dilute with Mobile phase to volume.

Chromatographic system

(See Chromatography 〈621〉, System Suitability) Mode: LC

Detector: UV 230 nm

Column: 2-mm × 15-cm; 3-µm packing L1 Flow rate: 0.2 mL/min

Injection volume: 15 µL System suitability

Sample: Standard solution

[NOTE—The retention time for sodium benzoate is about 6.5 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 sodium benzoate (C₇H₅NaO₂) in the portion of Oral Solution taken:

Result = (r_U/r_S) × (C_S/C_U) × 100

r_U = peak response of sodium benzoate from the Sample solution

r_S = peak response of sodium benzoate from the Standard solution

C_S = concentration of USP Sodium Benzoate RS in the Standard solution (mg/mL)

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

Acceptance criteria: 90.0%–110.0%

3 SPECIFIC TESTS

PH 〈791〉

For Oral Solution 100 mg/mL: 6.7–7.7

For Oral Solution 300 mg/mL: 7.3–8.3

4 ADDITIONAL REQUIREMENTS

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

BEYOND-USE DATE: NMT 90 days from the date on which it was prepared when stored at controlled room temperature or in a refrigerator.

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

USP REFERENCE STANDARDS 〈11〉

USP Sodium Benzoate RS (USP 1-May-2020)