Decoquinate Type A Medicated Article

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

Decoquinate Type A Medicated Article contains NLT 90.0% and NMT 110.0% of the labeled amount of decoquinate (C₂₄H₃₅NO₅), the labeled amount being between 1 g/100 g and 10 g/100 g of Decoquinate Type A Medicated Article.

2 IDENTIFICATION

2.1 A.

Standard solution: 2.5 mg/mL of USP Decoquinate RS in chloroform

Sample solution: To a weighed quantity of sample, equivalent to 100 mg of decoquinate, add 40 mL of chloroform, and heat under a reflux condenser on a water bath for 20 min, cool, and filter. Use the filtrate as the

Chromatographic system

(See Chromatography (621), General Procedures, Thin-Layer Chromatography.)

Mode: TLC

Adsorbent: 0.25-mm layer of chromatographic silica gel mixture

Application volume: 10 µL

Developing solvent system: Chloroform and alcohol (70:30)

Analysis

Samples: Standard solution and Sample solution

Apply the Standard solution and Sample solution to the starting line of the chromatographic plate. Allow the spots to dry, and develop the chromatogram in the Developing solvent system until the solvent front has moved about three-fourths of the length of the plate.

Remove the plate from the developing chamber, and allow to dry in a current of air. Locate the spots under short-wavelength UV light.

Acceptance criteria: The R, value of the principal spot of the Sample solution corresponds to that of the Standard solution.

3 ASSAY

3.1 PROCEDURE

Standard solution: 0.005 mg/mL of USP Decoquinate RS prepared as follows. Transfer 50 mg of USP Decoquinate RS to a 100-mL volumetric flask, add 10 mL of hot chloroform, swirl to dissolve, and while still warm, slowly add 70 mL of dehydrated alcohol. Allow to cool, and dilute with dehydrated alcohol to volume. Immediately transfer 10.0 mL of this solution to a second 100-mL volumetric flask, and dilute with dehydrated alcohol to volume. Transfer 10.0 mL of this solution to a third 100-mL volumetric flask, add 10 mL of 0.1 N hydrochloric acid, and dilute with dehydrated alcohol to volume.

Sample solution: Extract an accurately weighed quantity of Decoquinate Type A Medicated Article, equivalent to 200 mg of decoquinate, with 50 mL of chloroform in a small continuous extraction apparatus for eight reflux cycles. Transfer the extract to a 100-mL volumetric flask with the aid of chloroform, cool, and dilute with chloroform to volume. Transfer 5.0 mL of this solution to a second 100-mL volumetric flask, and dilute with dehydrated alcohol to volume. Transfer 5.0 mL of this solution to a third 100-mL volumetric flask, add 10 mL of 0.1 N hydrochloric acid, and dilute with dehydrated alcohol to volume.

Instrumental conditions.

Mode: UV

Analytical wavelength: Maximum absorbance at about 265 nm

Blank: Chloroform, dehydrated alcohol, and 0.1 N hydrochloric acid (0.25:90:10)

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of decoquinate (C24H3NO) in the portion of Decoquinate Type A Medicated Article 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 Decoquinate RS in the Standard solution (mg/mL) S

C_u = nominal concentration of decoquinate in the Sample solution (mg/mL) Cu

Acceptance criteria: 90.0%-110.0%

4 ADDITIONAL REQUIREMENTS

4.1 PACKAGING AND STORAGE: Preserve in well-closed containers.

4.2 LABELING: Label it to indicate that it is for veterinary use only.

4.3 USP REFERENCE STANDARDS (11)

USP Decoquinate RS