Testosterone 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

Testosterone Topical Solution contains NLT 90.0% and NMT 110.0% of the labeled amount of testosterone (C₁₉H₂₈O₂).

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

Solution A: Acetonitrile, water, and trifluoroacetic acid (10:90:0.05)

Solution B: Acetonitrile and trifluoroacetic acid (100:0.05)

Mobile phase: See Table 1.

Table 1

[Note—Post time of the gradient may be extended to more than 21 min to allow system to properly re-equilibrate.]

Diluent: Absolute alcohol and Solution A (50:50)

Standard stock solution: 0.8 mg/mL of USP Testosterone RS in absolute alcohol

Standard solution: 80 μg/mL of USP Testosterone RS from the Standard stock solution in Diluent

Sample solution: Nominally 80 μg/mL of testosterone from Topical Solution prepared as follows. Dispense a suitable amount of Topical

Solution to a screw-cap glass container, seal the container, and sonicate briefly to disperse bubbles. [Note—Do not store sample in an open container.] Transfer a suitable volume of the solution to an appropriate volumetric flask and dilute with Diluent to volume. Sonicate the resulting solution. [Note—Sonication for 30–60 s may be suitable.]

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 240 nm. For Identification B, use a diode array detector in the range of 210–400 nm.

Column: 3.9-mm × 15-cm; 5-μm packing L7. [Note—A guard column with a similar packing may be used.]

Flow rate: 0.7 mL/min

Injection volume: 10 μL

System suitability

Sample: Standard solution

Suitability requirements

Tailing factor: NMT 1.3

Relative standard deviation: NMT 1.0%

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of testosterone in the portion of Topical Solution taken:

Result = (r_U/r_S) × (C_S/C_U) × 100

r_U = peak response of testosterone from the Sample solution

r_S = peak response of testosterone from the Standard solution

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

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

Acceptance criteria: 90.0%–110.0%

4 IMPURITIES

Organic Impurities

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

Sensitivity solution: 0.11 μg/mL of USP Testosterone RS from the Standard solution in Diluent System suitability

Samples: Standard solution and Sensitivity solution

Suitability requirements

Tailing factor: NMT 1.3 for the testosterone peak, Standard solution

Signal-to-noise ratio: NLT 10, Sensitivity solution

Analysis

Sample: Sample solution

Calculate the percentage of each individual degradation product in the portion of Topical Solution taken:

Result = (r_U/r_T) × 100

r_U = peak response of each individual degradation product from the Sample solution

r_T = peak response of testosterone from the Sample solution

Acceptance criteria: See Table 2.

Table 2

5 SPECIFIC TESTS

Microbial Enumeration Tests 〈61〉 and Tests for Specified Microorganisms 〈62〉: The total aerobic microbial count does not exceed 102cfu/mL.

The total combined molds and yeasts count does not exceed 101cfu/mL. It meets the requirements of the tests for the absence of

Staphylococcus aureus and Pseudomonas aeruginosa.

6 ADDITIONAL REQUIREMENTS

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

USP Reference Standards 〈11〉

USP Testosterone RS

2S (USP41)