Atropine Sulfate 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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Atropine Sulfate Ophthalmic Solution

1 DEFINITION

Atropine Sulfate Ophthalmic Solution is a sterile, aqueous solution of Atropine Sulfate. It contains NLT 93.0% and NMT 107.0% of the labeled amount of atropine sulfate monohydrate (C₁₇H₂₃NO₃)₂ · H₂SO₄ · H₂O. It may contain suitable stabilizers and antimicrobial agents.

2 IDENTIFICATION

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

Delete the following:

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

Sample solution: Evaporate to dryness a quantity of Ophthalmic Solution. Prepare a solution from the residue that contains the equivalent of 50 mg of atropine sulfate/mL.

Acceptance criteria: Meets the requirements

Add the following:

B. The UV spectrum of the major peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay.▲ (IRA 1-Nov-2019)

3 ASSAY

Change to read:

Procedure

Buffer A: 6.8 g/L of sodium acetate in water. To each liter add 3.5 mL of triethylamine and 6.6 mL of glacial acetic acid. Adjust with glacial acetic acid, if needed, to a pH of 4.5.

Buffer B: 6.8 g/L of sodium acetate in water. To each liter add 4 mL of glacial acetic acid. Adjust with glacial acetic acid, if needed, to a pH of 4.5.

Mobile phase: Methanol and Buffer A (15:85)

Diluent: Methanol and Buffer B (15:85)

Standard solution: 0.5 mg/mL of USP Atropine Sulfate RS in Diluent

Sample solution: Nominally 0.5 mg/mL of atropine sulfate monohydrate from a volume of Ophthalmic Solution prepared as follows. Rinse a 100-mL volumetric flask with Diluent. Transfer about 33 mL of Diluent to the flask and then add a 5.0-mL aliquot of Ophthalmic Solution using a "to contain" pipet (see Volumetric Apparatus 〈31〉) to the flask. Shake vigorously. Dilute with Diluent to volume. Additional shaking may be needed to obtain a uniform solution.

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 225 nm. For Identification B, use a diode array detector in the range of 190–400 nm.

Column: 4.6-mm × 15-cm; 5-µm packing L10

Column temperature: 40°

Flow rate: 1.2 mL/min

Injection volume: 20 µL

Run time: NLT 3 times the retention time of atropine

System suitability

Sample: Standard solution

[Note—See Table 1 for the relative retention times.]

Suitability requirements

Tailing factor: NMT 2.0

Relative standard deviation: NMT 1.0%

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of atropine sulfate monohydrate 

(C₁₇H₂₃NO₃)₂ · H₂SO₄ · H₂O in the portion of Ophthalmic Solution taken:

Result = (rᵤ / rₛ) × (Cₛ/Cᵤ) × (Mᵣ₁ / Mᵣ₂) × 100

rᵤ = peak response of atropine from the Sample solution 

rₛ = peak response of atropine from the Standard solution

Cₛ = concentration of USP Atropine Sulfate RS in the Standard solution (mg/mL)

Cᵤ = nominal concentration of atropine sulfate in the Sample solution (mg/mL)

Mᵣ₁ = molecular weight of atropine sulfate monohydrate, 694.84

Mᵣ₂ = molecular weight of anhydrous atropine sulfate, 676.82▲ (IRA 1-Nov-2019)

Acceptance criteria: 93.0%–107.0%

4 IMPURITIES

Change to read:

Organic Impurities

Buffer A, Buffer B, Mobile phase, Diluent, Standard solution, Sample solution, and Chromatographic system: Proceed as directed in the Assay.

System suitability solution: 0.005 mg/mL of atropic acid and 0.5 mg/mL of USP Atropine Sulfate RS in Diluent

System suitability

Samples: Standard solution and System suitability solution

[Note—See Table 1 for the relative response factors.]

Suitability requirements

Resolution: NLT 1.5 between atropic acid and atropine, System suitability solution

Relative standard deviation: NMT 1.0%, Standard solution

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of each specified and any unspecified degradation product in the portion of Ophthalmic Solution taken:

Result = (rᵤ / rₛ) × (Cₛ / Cᵤ) × (1/F) × (Mᵣ₁ / Mᵣ₂) × 100

r₁ = peak response of each specified and any unspecified degradation product from the Sample solution

r₂ = peak response of atropine from the Standard solution

Cₛ = concentration of USP Atropine Sulfate RS in the Standard solution (mg/mL)

Cᵤ = nominal concentration of atropine sulfate in the Sample solution (mg/mL)

F = relative response factor (see Table 1)

Mᵣ₁ = molecular weight of atropine sulfate monohydrate, 694.84

Mᵣ₂ = molecular weight of anhydrous atropine sulfate, 676.82

Acceptance criteria: See Table 1.

ᵃ 3-Hydroxy-2-phenylpropanoic acid.

ᵇ 2-Phenylacrylic acid.

ᶜ (1R,3r,5S)-8-Methyl-8-azabicyclo[3.2.1]octan-3-yl 2-phenylacrylate.▲ (IRA 1-Nov-2019)

5 SPECIFIC TESTS

pH 〈791〉: 3.5–6.0

Sterility Tests 〈71〉: Meets the requirements

6 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in tight containers, and store at controlled room temperature.

USP Reference Standards 〈11〉

USP Atropine Sulfate RS