Latanoprost Compounded Topical 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

Latanoprost Compounded Topical Solution contains NLT 90.0% and NMT 110.0% of the labeled amount of latanoprost (C₂₆H₄₀O₅ ).

Prepare Latanoprost Compounded Topical Solution 0.1 mg/mL as follows (see Pharmaceutical Compounding—Nonsterile Preparations 〈795〉).

For this preparation, a separate stock solution of latanoprost 10 mg/g needs to be prepared.

Prepare a latanoprost stock solution by weighing Latanoprost in a suitable container. Add a sufficient amount of Propylene Glycol to bring to final weight. Seal the container and mix by using ultrasonication for 15 min.

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Add Latanoprost 10 mg/g stock solution, Alcohol, and Pracamac Oil to an appropriately sized container. Add approximately 80 mL of Purified Water and mix well. Add a sufficient amount of Purified Water to bring to final volume and mix well.

2 ASSAY

Procedure

Solution A: 0.1% (v/v) trifluoroacetic acid in water

Solution B: 0.1% (v/v) trifluoroacetic acid in acetonitrile

Mobile phase: See Table 1.

Table 1

Standard solution: 0.04 mg/mL of USP Latanoprost RS in methanol

Sample solution: Transfer 2 mL of the Topical Solution into a 5-mL volumetric flask and dilute with methanol to bring to volume. Mix well.

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 210 nm

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

Temperatures

Autosampler: 8°

Column: 65°

Flow rate: 1 mL/min

Injection volume: 2 μL

System suitability

Sample: Standard solution

[Note—The typical retention time for latanoprost is about 0.99 min.]

Suitability requirements

Tailing factor: NMT 2.0

Relative standard deviation: NMT 2.0% for replicate injections

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of latanoprost (C₂₆H₄₀O₅ ) in the portion of Topical Solution taken:

Result = (r_U/r_S)x(C_S/C_U) × 100

r_U = peak response of latanoprost from the Sample solution

r_S = peak response of latanoprost from the Standard solution

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

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

Acceptance criteria: 90.0%–110.0%

3 SPECIFIC TESTS

pH 〈791〉: 7.0–8.0

4 ADDITIONAL REQUIREMENTS

Packaging and Storage: Package in tight, light-resistant containers. Store at controlled room temperature or in a refrigerator.

Beyond-Use Date: NMT 60 days after the date on which it was compounded when stored at controlled room temperature. NMT 180 days after

the date on which it was compounded when stored in a refrigerator.

Labeling: Label it to indicate that it is for external use only and not for use in the eye. Label it to state the Beyond-Use Date.

USP Reference Standards 〈11〉

USP Latanoprost RS (USP 1-Dec-2021)