Tretinoin Gel

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

Tretinoin Gel contains NLT 90.0% and NMT 130.0% of the labeled amount of C₂₀H₂₈O₂

2 IDENTIFICATION

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

3 ASSAY

PROCEDURE

[NOTE-Avoid exposure to strong light, and use low-actinic glassware in the performance of the following procedure.]

Mobile phase: Prepare a mixture of acetonitrile and water (17:3). Add 5 mL of glacial acetic acid to each L of the mixture, mix well, filter, and degas.

Standard solution: 0.02 mg/ml. of USP Tretinoin RS in methanol. [NOTE-Sonicate if needed.]

Sample solution: Transfer Tretinoin Gel, equivalent to 2 mg of tretinoin, to a 100-mL volumetric flask. Add about 70 mL of methanol, sonicate with intermittent shaking for 30 min, and dilute with methanol to volume. Centrifuge a portion of this solution at 3000 rpm for 10 min. Use the clear supernatant.

Chromatographic system

(See Chromatography (621), System Suitability.)

Mode: LC

Detector: UV 353 nm

Column: 4.6-mm x 15-cm; 5-µm packing L1

Flow rate: 1.5 mL/min

Injection size: 20 µL

Autosampler temperature: 15°

System suitability

Sample: Standard solution

Suitability requirements

Relative standard deviation: NMT 2.0%

Tailing factor: NMT 2.0

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of C₂₀H₂₈O₂, in the portion of Gel taken:

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

r_U = peak response from the Sample solution

r_S = peak response from the Standard solution

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

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

Acceptance criteria: 90.0%-130.0%

4 PERFORMANCE TESTS

MINIMUM FILL (755): Meets the requirements

5 ADDITIONAL REQUIREMENTS

PACKAGING AND STORAGE: Preserve in tight containers, protected from light.

USP REFERENCE STANDARDS (11)

USP Tretinoin RS