Diloxanide Furoate

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 

Diloxanide Furoate contains NLT 98.0% and NMT 102.0% of diloxanide furoate (C₁₄H₁₁Cl₂NO₄), calculated on the dried basis. 

2 IDENTIFICATION

Change to read: 

2.1 A. Spectroscopic Identification Tests 〈197〉, Infrared Spectroscopy: 197K (CN 1-May-2020) 

Change to read: 

2.2 B. Spectroscopic Identification Tests 〈197〉, Ultraviolet-Visible Spectroscopy: 197U (CN 1-May-2020) 

Analytical wavelength: 258 nm 

Sample solution: 14 µg/mL in alcohol 

Acceptance criteria: Meets the requirements 

2.3 C. 

Sample: 20 mg 

Analysis: Burn the Sample by using the method in oxygen Flask Combustion 〈471〉 using 10 mL of 1 N sodium hydroxide as the absorbing liquid. When the process is complete, acidify the liquid with nitric acid, and add a solution of silver nitrate (5 in 100).

Acceptance criteria: A white precipitate forms. 

3 ASSAY 

3.1 Procedure 

Sample solution: 300 mg of Diloxanide Furoate in 50.0 mL of dried pyridine 

Titrimetric system 

(See Titrimetry 〈541〉.) 

Mode: Direct titration 

Titrant: 0.1 N tetrabutylammonium hydroxide VS 

Endpoint detection: Potentiometric 

Analysis: Titrate the Sample solution with Titrant. Perform a blank determination. Each mL of 0.1 N tetrabutylammonium hydroxide is equivalent to 32.82 mg of diloxanide furoate (C₁₄H₁₁Cl₂NO₄). 

Acceptance criteria: 98.0%–102.0% on the dried basis 

4 IMPURITIES 

4.1 Residue on Ignition 〈281〉: NMT 0.1% 

4.2 Organic Impurities 

Standard solution: Dilute 0.5 mL of Sample solution with chloroform to 200 mL. 

Sample solution: 100 mg/mL of Diloxanide Furoate in chloroform 

Chromatographic system 

(See Chromatography 〈621〉, Thin-Layer Chromatography.) 

Mode: TLC 

Adsorbent: 0.25-mm layer of chromatographic silica gel mixture 

Application volume: 5 µL 

Developing solvent system: Dichloromethane and methanol (96:4) 

Analysis: Examine the plate under short-wavelength UV light. 

Acceptance criteria: Any secondary spot obtained from the Sample solution is not more intense than the spot obtained from the Standard solution. 

5 SPECIFIC TESTS 

5.1 Melting Range or Temperature 〈741〉: 114°–116° 

5.2 Acidity 

Sample solution: Shake 3 g of Diloxanide Furoate in 50 mL of water. Filter, wash the residue with three 20-mL portions of water, and combine the ltrate and washings. 

Analysis: Titrate the Sample solution with 0.1 N sodium hydroxide VS using phenolphthalein TS as the indicator. 

Acceptance criteria: NMT 1.3 mL of 0.1 N sodium hydroxide is required for neutralization 

5.3 Loss on Drying 〈731〉 

Analysis: Dry at 105° to constant weight. 

Acceptance criteria: NMT 0.5% 

6 ADDITIONAL REQUIREMENTS 

Packaging and Storage: Preserve in tight, light-resistant containers at controlled room temperature. 

USP Reference Standards 〈11〉 

USP Diloxanide Furoate RS