Amitraz Concentrate for Dip

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

Amitraz Concentrate for Dip contains amitraz in a suitable vehicle. It may contain a suitable stabilizing agent. It contains NLT 90.0% and NMT 120.0% of the labeled amount of amitraz (C₁₉H₂₃N₃).

2 IDENTIFICATION

2.1 A. THIN-LAYER CHROMATOGRAPHY

Standard solution: 5 mg/mL of USP Amitraz RS in toluene

Sample solution: Nominally 5 mg/mL of amitraz from Concentrate for Dip diluted with toluene

Chromatographic system

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

Mode: TLC

Adsorbent: 0.25-mm layer of chromatographic silica gel mixture

Application volume: 2 µL

Developing solvent system: Cyclohexane, ethyl acetate, and triethylamine (5:3:2)

Spray reagent: 0.5% solution of N-(1-naphthyl)ethylenediamine dihydrochloride in methanol

Analysis

Samples: Standard solution and Sample solution

Stand the plate to a depth of 3.5 cm in a solution prepared by dissolving 35 g of acetamide in 100 mL of methanol, adding 100 mL of triethylamine, and diluting to 250 mL with methanol. Allow the wet plate to stand in a current of cold air for 30 s. Immediately apply the Samples separately to the plate, at a level about 1 cm below the top of the impregnated zone. Promptly develop the plate until the solvent front has moved three-fourths of the length of the plate. Remove the plate from the developing chamber and allow to air-dry. Examine the plate under short-wavelength UV light.

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

2.2 B.

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

3 ASSAY

3.1 PROCEDURE

Internal standard solution: 0.7% v/v solution of squalane in methyl acetate

Standard solution: 5.0 mg/mL of USP Amitraz RS in Internal standard solution

Sample solution: Nominally equivalent to 5.0 mg/mL of amitraz from Concentrate for Dip in Internal standard solution

3.2 Chromatographic system

(See Chromatography (621), System Suitability.)

Mode: GC

Detector: Flame ionization

Column: 0.53-mm x 15-m fused silica; coated with a 1.5-µm layer of liquid phase G9

Temperatures

Column: 220°

Inlet: 230°

Detector: 300°

Carrier gas: Helium

Flow rate: 12 mL/min

Injection volume: 1 µL

3.3 System suitability

Sample: Standard solution

[NOTE-The elution order is amitraz, followed by squalane.]

Suitability requirements

Resolution: NLT 3.0 between amitraz and squalane

Relative standard deviation: NMT 2.0% from the peak area ratio of amitraz to squalane

3.4 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of amitraz (C₁₉H₂₃N₃) in the portion of Concentrate for Dip taken:

Result = (R_U/R_S) x (C_S/C_U) x 100

R_U = peak response ratio of amitraz and squalane from the Sample solution

R_S = peak response ratio of amitraz and squalane from the Standard solution

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

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

Acceptance criteria: 90.0%-120.0%

4 SPECIFIC TESTS

WATER DETERMINATION, Method (921): NMT 0.15%

5 ADDITIONAL REQUIREMENTS

5.1 PACKAGING AND STORAGE

Preserve in well-closed containers.

5.2 LABELING

Label it to indicate that it is for veterinary use only and that it is to be diluted before use. The label also states the name and quantity of diluent to be used, the directions for dilution, and the conditions for storage of the constituted Concentrate for Dip.

5.3 USP REFERENCE STANDARDS (11).

USP Amitraz RSA (USP 1-Dec-2024)