Betaxolol 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

Betaxolol Ophthalmic Solution is a sterile, aqueous, isotonic solution of Betaxolol Hydrochloride. It contains a suitable antimicrobial preservative. It contains the equivalent of NLT 90.0% and NMT 110.0% of the labeled amount of betaxolol (C₁₈H₂₉NO₃).

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. The UV spectrum of the major peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay.

3 ASSAY

Procedure

Buffer: Dissolve 7.1 g of anhydrous dibasic sodium phosphate in 800 mL of water, adjust with phosphoric acid to a pH of 3.0, and dilute with water to 1000 mL.

Mobile phase: Acetonitrile and Buffer (1:1)

Standard solution: 0.11 mg/mL of USP Betaxolol Hydrochloride RS in Buffer

Sample solution: Nominally 0.1 mg/mL of betaxolol in Buffer from Ophthalmic Solution

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV or diode array 280 nm. [Note—Use the diode array detector to perform Identification test B.]

Column: 4-mm × 25-cm; packing L1

Flow rate: 1.1 mL/min

Injection volume: 10 µL

System suitability

Sample: Standard solution

Suitability requirements

Tailing factor: 0.8–2.0

Relative standard deviation: NMT 2.0%

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of betaxolol (C₁₈H₂₉NO₃) in the portion of Ophthalmic Solution taken:

Result = (r₁/r₂) × (C₁/C₂) × (M₁/M₂) × 100

r₁ = peak response from the Sample solution

r₂ = peak response from the Standard solution

C₁ = concentration of USP Betaxolol Hydrochloride RS in the Standard solution (mg/mL)

C₂ = nominal concentration of betaxolol in the Sample solution (mg/mL)

M₁ = molecular weight of betaxolol, 307.43

M₂ = molecular weight of betaxolol hydrochloride, 343.89

Acceptance criteria: 90.0%–110.0%

4 IMPURITIES

Organic Impurities

Mobile phase: Add 5 mL of phosphoric acid to 990 mL of water. Adjust with 2 M ammonium hydroxide to a pH of 3.0, and dilute with water to 1000 mL. Prepare a mixture of this solution and acetonitrile (45:55). Dissolve 3 g of sodium dodecyl sulfate in 450 mL of the mixture.

Standard solution: 2.2 µg/mL of USP Betaxolol Hydrochloride RS in Mobile phase

Sample solution: Nominally equivalent to 0.2 mg/mL of betaxolol in Mobile phase from Ophthalmic Solution

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: 220 nm

Column: 4.6-mm × 25-cm; 10-µm packing L1

Flow rate: 1.5 mL/min

Injection volume: 20 µL

System suitability

Sample: Standard solution

Suitability requirements

Relative standard deviation: NMT 5%

Tailing factor: NMT 2.5

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of each impurity in the portion of Ophthalmic Solution taken:

Result = (r₁/r₂) × (C₁/C₂) × (M₁/M₂) × 100

r₁ = peak response of each impurity from the Sample solution

r₂ = peak response of betaxolol from the Standard solution

C₁ = concentration of USP Betaxolol Hydrochloride RS in the Standard solution (mg/mL)

C₂ = nominal concentration of betaxolol in the Sample solution (mg/mL)

M₁ = molecular weight of betaxolol, 307.43

M₂ = molecular weight of betaxolol hydrochloride, 343.89

Acceptance criteria

Single largest individual impurity: NMT 1%

Any other individual impurity: NMT 0.3%

5 SPECIFIC TESTS

Sterility Tests 〈71〉: It meets the requirements when tested as directed for Test for Sterility of the Product to Be Examined, Membrane Filtration.

pH 〈791〉: 4.0–8.0

6 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in tight containers. Store at room temperature.

USP Reference Standards 〈11〉

USP Betaxolol Hydrochloride RS