Atropine Sulfate Ophthalmic Ointment

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 Ointment

1 DEFINITION

Atropine Sulfate Ophthalmic Ointment is Atropine Sulfate in a suitable ophthalmic ointment base. It contains NLT 90.0% and NMT 110.0% of the labeled amount of atropine sulfate monohydrate (C₁₇H₂₃NO₃)₂·H₂SO₄·H₂O It is sterile

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.

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

Sample solution: Transfer 5 g of Ophthalmic Ointment to a separator, dissolve in 50 mL of ether, and extract with 20 mL of water.

Acceptance criteria: Meets the requirements

3 ASSAY

Change to read:

Procedure

Solution A: Stronger ammonia water and water (1:100), adjusted with perchloric acid to a pH of 3.0

Solution B: Acetonitrile

Mobile phase: See Table 1.

Diluent: Acetonitrile and Solution A (25:75)

System suitability solution: 1.0 µg/mL each of USP Atropine Sulfate RS and littorine hydrochloride in Diluent

Standard solution: 0.1 mg/mL of USP Atropine Sulfate RS in Diluent

Sample stock solution: Nominally 0.5 mg/mL of atropine sulfate from a portion of Ophthalmic Ointment prepared as follows. Transfer 10 mg of atropine sulfate from a portion of Ophthalmic Ointment to a stoppered 250-mL flask, add 20 mL of Diluent, and shake at 40° for 60 min. Centrifuge and use the lower layer clear solution.

[Note—The use of a centrifuge speed of 4000 rpm for 10 min may be suitable.]

Sample solution: Nominally 0.1 mg/mL of atropine sulfate from the Sample stock solution in Diluent

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

[Note—Rinse the system with water after each set of analysis.]

Mode: LC

Detector: UV 210 nm

Column: 2.1-mm × 10-cm; 1.8-µm packing L96

Column temperature: 30°

Flow rate: 0.4 mL/min

Injection volume: 3 µL

System suitability

Samples: System suitability solution and Standard solution

[Note—The relative retention times for atropine and littorine are 1.0 and 1.04, respectively.]

Resolution: NLT 2.0 between atropine and littorine, System suitability solution

Tailing factor: NMT 1.5, Standard solution

Relative standard deviation: NMT 1.0%, Standard solution

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 Ointment taken:

Result = (r_U / r_S) × (C_S / C_U) × (M₁ / M₂) × 100

r_U = peak response of atropine from the Sample solution

r_S= peak response of atropine from the Standard solution

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

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

M₁ = molecular weight of atropine sulfate monohydrate, 694.84

M₂ = molecular weight of anhydrous atropine sulfate, 676.82

Acceptance criteria: 90.0%–110.0%

4 IMPURITIES

Organic Impurities

Solution A, Solution B, Mobile phase, Diluent, System suitability solution, and Chromatographic system: Proceed as directed in the Assay.

Standard solution: 1.0 µg/mL of USP Atropine Sulfate RS in Diluent

Sample solution: Nominally 500 µg/mL of atropine sulfate from a portion of Ophthalmic Ointment prepared as follows. Transfer a portion of Ophthalmic Ointment equivalent to 25 mg of atropine sulfate to a stoppered 250-mL flask, add 50 mL of Diluent, and shake at 40° for 60 min. Centrifuge and use the lower layer clear solution. [Note—The use of a centrifuge speed of 4000 rpm for 10 min may be suitable.]

System suitability

Samples: System suitability solution and Standard solution

[Note—The relative retention times for atropine and littorine are 1.0 and 1.04, respectively.]

Resolution: NLT 2.0 between atropine and littorine, System suitability solution

Relative standard deviation: NMT 5.0%, 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 Ointment taken:

Result =(r_U / r_S) × (C_S / C_U) × (1/F) × 100

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

r_S= peak response of atropine from the Standard solution

C_S = concentration of USP Atropine Sulfate RS in the Standard solution (µg/mL)

C_U= nominal concentration of atropine sulfate in the Sample solution (µg/mL)

F = relative response factor (see Table 2)

Acceptance criteria: See Table 2. Disregard peaks less than 0.1%

ᵃ 3-Hydroxy-2-phenylpropanoic acid

ᵇ (S)-(1R,2R,4S,5S,7S)-9-Methyl-3-oxa-9-azatricyclo[3.3.1.0²,⁴]nonan-7-yl 3-hydroxy-2-phenylpropanoate

ᶜ (1R,3r,5S)-8-Azabicyclo[3.2.1]octan-3-yl (S)-3-hydroxy-2-phenylpropanoate

ᵈ (1R,3r,5S)-8-Methyl-8-azabicyclo[3.2.1]octan-3-yl 2-phenylacrylate

5 SPECIFIC TESTS

Sterility Tests 〈71〉: Meets the requirements

Other Requirements: It meets the requirements for Particulate and Foreign Matter in Ophthalmic Products—Quality Tests 〈771〉, Drug Product Quality, Universal Tests, Particulate and Foreign Matter.

6 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in collapsible ophthalmic ointment tubes. Store at controlled room temperature.

USP Reference Standards 〈11〉: USP Atropine Sulfate RS