Sodium Chloride Ophthalmic 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 Chloride Ophthalmic Solution is a sterile solution of Sodium Chloride. It contains NLT 90.0% and NMT 110.0% of the labeled amount of sodium chloride (NaCl). It may contain suitable antimicrobial and stabilizing agents. It contains a buffer.

2 IDENTIFICATION

A. Identification Tests—General 〈191〉, Chemical Identification Tests, Sodium

Sample solution: Heat a portion of Ophthalmic Solution to boiling, and filter while hot. Use the filtrate after cooling.

Acceptance criteria: Meets the requirements

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B. Identification Tests—General 〈191〉, Chemical Identification Tests, Chloride

Sample solution: Heat a portion of Ophthalmic Solution to boiling, and filter while hot. Use the filtrate after cooling.

Acceptance criteria: Meets the requirements (USP 1-Aug-2021)

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B. The retention time of the chloride peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay.(USP 1-Aug-2021)

3 ASSAY

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Procedure

Use water with a resistivity of NLT 18 megohm-cm to prepare the solutions.

Solution A: 100 mM potassium hydroxide

Solution B: Water

Mobile phase: See Table 1. [Note—Alternatively, Mobile phase can be generated electrolytically using an automatic eluant generator.]

Table 1

System suitability solution: 100 μg/mL of USP Sodium Chloride RS and 8 μg/mL of USP Sodium Nitrite RS in water

Standard solution: 100 μg/mL of USP Sodium Chloride RS in water

Sample solution: Nominally 100 μg/mL of sodium chloride from a suitable volume of Ophthalmic Solution in water

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: Conductivity with suppression

Columns

Guard: 4.0-mm × 5-cm; 11-μm packing L121. [Note—Alternatively, a 4.0-mm × 0.5-cm column that contains 5.0-μm packing L91 may be used.]

Analytical: 4.0-mm × 25-cm; 7.5-μm packing L103. [Note—Alternatively, a 4.0-mm × 15-cm column that contains 5.0-μm packing L91 may be used.]

Column temperature: 35°

Flow rate: 1.2 mL/min

Injection volume: 10 μL

System suitability

Samples: System suitability solution and Standard solution

[Note—The relative retention times for the chloride and nitrite peaks are 1.0 and 1.1, respectively.]

Suitability requirements

Resolution: NLT 2.0 between the chloride and nitrite peaks, System suitability solution

Tailing factor: NMT 2.0 for the chloride and nitrite peaks, System suitability solution

Relative standard deviation: NMT 2.0%, Standard solution

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of sodium chloride (NaCl) in the portion of Ophthalmic Solution taken:

Result = (r_U/r_S) × (C_S/C_U) × 100

r_U = peak response of chloride from the Sample solution

r_S = peak response of chloride from the Standard solution

C_S = concentration of USP Sodium Chloride RS in the Standard solution (μg/mL)

C_U = nominal concentration of sodium chloride in the Sample solution (μg/mL)

Acceptance criteria: 90.0%–110.0% (USP 1-Aug-2021)

4 SPECIFIC TESTS

Sterility Tests 〈71〉: Meets the requirements

pH 〈791〉: 6.0–8.0

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Other Requirements: It meets the requirements in Ophthalmic Products—Quality Tests 〈771〉. (USP 1-Aug-2021)

5 ADDITIONAL REQUIREMENTS

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Packaging and Storage: Preserve in tight containers, and store at controlled room temperature. (USP 1-Aug-2021)

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USP Reference Standards 〈11〉

USP Sodium Chloride RS

USP Sodium Nitrite RS (USP 1-Aug-2021)