Gentian Violet Cream

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

Gentian Violet Cream is Gentian Violet in a suitable cream base. It contains, in each 100 g, NLT 1.20 g and NMT 1.60 g of gentian violet (C₂₅H₃₀ClN₃).

2 IDENTIFICATION

A.

Sample: 0.1 g

Analysis: Dissolve the Sample in 5 mL of sulfuric acid.

Acceptance criteria: An orange or brown-red color is produced.

B. The visible absorption spectrum of the Sample solution used for measurement of absorbance in the Assay exhibits maxima at the same wavelengths as that of a similar solution of USP Gentian Violet RS, concomitantly measured.

3 ASSAY

3.1 Procedure

Standard solution: 13.5 μg/mL of USP Gentian Violet RS in hydrochloric acid

Sample stock solution: Transfer 500 mg of Cream to a 100-mL volumetric flask. Add 15 mL of hydrochloric acid, warm in a water bath to disperse the Cream thoroughly, cool, and add hydrochloric acid to volume. Pass the mixture through a sintered-glass filter of fine pore size.

Sample solution: Pipet 2 mL of the Sample stock solution into a 10-mL volumetric flask, and add hydrochloric acid to volume.

Blank: Hydrochloric acid

3.2 Instrumental conditions

Analytical wavelength: 435 nm

Cell: 1 cm. [Note - Use quartz cells having tightly fitting covers to prevent the corrosion caused by hydrochloric acid.]

3.3 Analysis

Samples: Standard solution and Sample solution

Calculate the quantity, in g/100 g, of gentian violet (C₂₅H₃₀ClN₃) in the portion of Cream taken:

Result = (A_U/A_S) × C_S × (1/W) × V × D × (1/F) × 100

A_U = absorbance from the Sample solution

A_S = absorbance from the Standard solution

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

W = weight of the sample in the Sample stock solution, 0.5 g

V = volume of the Sample stock solution, 100 mL

D = dilution factor, 5

F = conversion factor, 106 μg/g

Acceptance criteria: It contains, in each 100 g, 1.20–1.60 g of gentian violet (C H ClN ).

4 PERFORMANCE TESTS

Minimum Fill 〈755〉: Meets the requirements

5 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in collapsible tubes or other tight containers, and avoid exposure to excessive heat.

USP Reference Standards 〈11〉

USP Gentian Violet RS