Sodium Salicylate Tablets

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 Salicylate Tablets contain NLT 95.0% and NMT 105.0% of the labeled amount of sodium salicylate (C₇H₅NaO₃).

2 IDENTIFICATION

A.

Sample: 50 mg/mL of sodium salicylate in water from powdered Tablets. Filter and use the filtrate.

Acceptance criteria: The sample imparts an intense yellow color to a nonluminous flame.

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

3 ASSAY

Procedure

Mobile phase: Methanol, trifluoroacetic acid, and water (40:0.1:60). Prepare by adding 1 mL of trifluoroacetic acid to a solution containing 400 mL of methanol and 600 mL of water.

Standard solution: 0.04 mg/mL of USP Sodium Salicylate RS in Mobile phase

Sample stock solution: Nominally 0.4 mg/mL of sodium salicylate from NLT 20 finely powdered Tablets in Mobile phase prepared as follows.

Transfer a suitable amount of the powder to a suitable volumetric flask. Add 60% of the flask volume of Mobile phase, and sonicate for 10 min. Allow the solution to cool to room temperature and then dilute with Mobile phase to volume.

Sample solution: Nominally 0.04 mg/mL of sodium salicylate in Mobile phase from Sample stock solution. Pass through a suitable filter of 0.20-μm pore size, discarding the first 2–3 mL of the filtrate.

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 212 nm

Column: 2.1-mm × 5-cm; 1.7-μm packing L1

Column temperature: 30°

Flow rate: 0.2 mL/min

Injection volume: 2 μL

System suitability

Sample: Standard solution

Suitability requirements

Tailing factor: 0.8–1.8

Relative standard deviation: NMT 1.0%

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of sodium salicylate (C₇H₅NaO₃) in the portion of Tablets taken:

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

r_U = peak response from the Sample solution

r_S = peak response from the Standard solution

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

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

Acceptance criteria: 95.0%–105.0%

4 PERFORMANCE TESTS

Dissolution 〈711〉

Medium: Water; 900 mL

Apparatus 1: 100 rpm

Time: 45 min

Standard solution: A known concentration of USP Sodium Salicylate RS in Medium

Sample solution: Filter portions of the solution under test, and dilute with water, if necessary.

Instrumental conditions

Mode: UV

Analytical wavelength: Maximum absorbance at about 230 nm

Analysis: Determine the amount of sodium salicylate (C₇H₅NaO₃) dissolved from UV absorbance of the Sample solution, in comparison with

that of the Standard solution.

Tolerances: NLT 75% (Q) of the labeled amount of sodium salicylate (C₇H₅NaO₃ ) is dissolved.

Uniformity of Dosage Units 〈905〉: Meet the requirements

5 IMPURITIES

Organic Impurities

Mobile phase: Methanol, trifluoroacetic acid, and water (40:0.1:60). Prepare by adding 1 mL of trifluoroacetic acid to a solution containing 400 mL of methanol and 600 mL of water.

System suitability solution: 0.5 mg/mL of USP Sodium Salicylate RS, 0.5 μg/mL of USP Salicylic Acid Related Compound A RS, 0.5 μg/mL of

USP Salicylic Acid Related Compound B RS, and 0.5 μg/mL of USP Phenol RS in Mobile phase

Standard solution: 2.5 μg/mL of USP Sodium Salicylate RS in Mobile phase

Sample solution: Nominally 2.5 mg/mL of sodium salicylate from NLT 20 finely powdered Tablets in Mobile phase prepared as follows.

Transfer a suitable amount of the powder to a suitable volumetric flask. Add 60% of the flask volume of Mobile phase, and sonicate for 15 min. Allow the solution to cool to room temperature and then dilute with Mobile phase to volume. Centrifuge the solution, and use the supernatant.

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 212 nm

Column: 2.1-mm × 5-cm; 1.7-μm packing L1

Column temperature: 30°

Flow rate: 0.2 mL/min

Injection volume: 2 μL

System suitability

Samples: System suitability solution and Standard solution

Suitability requirements

Resolution: NLT 3.0 between salicylic acid related compound A and phenol; NLT 3.0 between phenol and salicylic acid related compound B, System suitability solution

Relative standard deviation: NMT 2%, Standard solution

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of any individual unspeciFIed impurity in the portion of Tablets taken:

Result = (r_U/r ) × (C /C_U) × 100

r_U = peak response of any individual unspecified impurity from the Sample solution

r_S = peak response of sodium salicylate from the Standard solution

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

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

Acceptance criteria: See Table 1.

Table 1

^a These are process impurities, which are included in the table for identification only. These impurities are controlled in the drug substance. They are not to be reported for the drug product and should not be included in the total impurities.

6 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in well-closed containers.

USP Reference Standards 〈11〉

USP Phenol RS

USP Salicylic Acid Related Compound A RS

4-Hydroxybenzoic acid.

C₇H₆O₃ 138.12

USP Salicylic Acid Related Compound B RS

4-Hydroxyisophthalic acid.

C₈H₆O₅ 182.13

USP Sodium Salicylate RS