Pramoxine Hydrochloride Jelly

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

Pramoxine Hydrochloride Jelly contains NLT 94.0% and NMT 106.0% of the labeled amount of pramoxine hydrochloride (C₁₇H₂₇NO₃ · HCl). 

2 IDENTIFICATION

A.

Sample solution: Place nominally 5 mg of pramoxine hydrochloride from a quantity of Jelly in a glass-stoppered conical ask. Add 25 mL of chloroform, and shake for 15 min. Filter into a small porcelain evaporating dish, and evaporate in a current of air on a steam bath. Analysis: Add 1 drop of nitric acid to the residue. To the resulting yellow solution cautiously add 5 drops of ammonium hydroxide. Acceptance criteria: A red-brown precipitate is formed.

3 ASSAY

Procedure

Standard solution: 150 µg/mL of USP Pramoxine Hydrochloride RS in 0.5 N sulfuric acid

Sample solution

[Note—If emulsions form, 2–5 mL of alcohol may be added to separate the phases.]

Transfer nominally 15 mg of pramoxine hydrochloride from a quantity of Jelly to a small beaker, and dissolve the Jelly in 0.1 N sulfuric acid, using four 5-mL portions. Warm each portion on a steam bath, and transfer to a 125-mL separator. Shake the separator vigorously after each transfer to complete the dissolution of the Jelly. To the cooled solution in the separator add 20 mL of ether, shake carefully, and proceed as directed in Salts of Organic Nitrogenous Bases 〈501〉, Assay Preparation, beginning with “filter the acid phase into a second 125-mL separator”, except to combine the nal 0.5 N sulfuric acid extracts in a 100-mL volumetric ask. Dilute with the acid to volume.

3.1 Instrumental conditions

Mode: UV

Analytical wavelength: 286 nm

3.2 Analysis

Samples: Standard solution and Sample solution

Proceed as directed in Salts of Organic Nitrogenous Bases 〈501〉, Procedure, diluting 20.0 mL each of the Standard solution and the Sample solution with 0.5 N sulfuric acid to 50.0 mL.

Calculate the percentage of the labeled amount of pramoxine hydrochloride (C₁₇H₂₇NO₃ · HCl) in the portion of Jelly taken: 

Result = (A_U /A_S ) × (C_S /C_U ) × 100

A_U = absorbance of the Sample solution

A_S = absorbance of the Standard solution

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

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

Acceptance criteria: 94.0%–106.0%

4 SPECIFIC TESTS

Microbial Enumeration Tests 〈61〉andTests for Specified Microorganisms 〈62〉: It meets the requirements of the tests for the absence of Staphylococcus aureus and Pseudomonas aeruginosa.

5 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in tight containers, preferably in collapsible tubes.

USP Reference Standards 〈11〉

USP Pramoxine Hydrochloride RS