Clorsulon

This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition

Issued and maintained by the United States Pharmacopeial Convention (USP)

DOWNLOAD PDF HERE

C₈H₈CI₃N₃O₄S₂                      380.66

1,3-Benzenedisulfonamide, 4-amino-6-(trichloroethenyl)-;

4-Amino-6-(trichlorovinyl)-m-benzenedisulfonamide CAS RN: 60200-06-8; UNII: EG1ZD06LRD.

1 DEFINITION

Clorsulon contains NLT 98.0% and NMT 101.0% of clorsulon (C₈H₈CI₃N₃O₄S₂), calculated on the dried basis.

2 IDENTIFICATION

Change to read:

A. ^▲Spectroscopic Identification Tests 〈197〉, Infrared Spectroscopy: 197M_{▲ (CN 1-May-2020)}

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

3 ASSAY

3.1 PROCEDURE

[NOTE-Store the Standard solution and the Sample solution in low-actinic glassware.]

Mobile phase: Acetonitrile, glacial acetic acid, and water (30:0.1:70)

Standard solution: 0.1 mg/mL of USP Clorsulon RS in Mobile phase

Sample stock solution: 1 mg/mL of Clorsulon in Mobile phase

Sample solution: 0.1 mg/mL of Clorsulon in Mobile phase, from the Sample stock solution

3.1.1 Chromatographic system

Mode: LC

Detector: UV 254 nm

Column: 4.6-mm × 25-cm; packing L7

Flow rate: 1 mL/min

Injection volume: 30 μL

3.1.2 System suitability

Sample: Standard solution

Suitability requirements

Column efficiency: NLT 7400 theoretical plates

Tailing factor: NMT 1.4

Relative standard deviation: NMT 1.0%

3.1.3 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of clorsulon (CHCINOS) in the portion of Clorsulon taken:

                Result = (r_U/r_S) x (C_S/C_U) × 100

r_U = peak response from the Sample solution

r_S = peak response from the Standard solution S

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

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

Acceptance criteria: 98.0%-101.0% on the dried basis

4 IMPURITIES

RESIDUE ON IGNITION (281): NMT 0.1%

4.1 ORGANIC IMPURITIES

[ NOTE-Store the Standard solutions and the Sample solution in low-actinic glassware.]

Standard solution A: 10 mg/mL of USP Clorsulon RS in methanol

Standard solution B: 0.1 mg/mL of USP Clorsulon RS in methanol, from Standard solution A

Sample solution: 10 mg/mL of Clorsulon in methanol

4.1.1 Chromatographic system

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

Mode: TLC

Adsorbent: 0.25-mm layer of chromatographic silica gel mixture

Developing solvent system: Chloroform and methanol (4:1)

4.1.2 Analysis 1

Samples: Standard solution A, Standard solution B, and Sample solution

Apply 10 µL each of the Sample solution and Standard solution A, and 5 and 10 µL of Standard solution B. Allow the spots to dry. Develop in Developing solvent system until the solvent front has moved three-fourths of the length of the plate. Remove the plate, mark the solvent front, allow the solvent to evaporate, and examine the plate under short-wavelength UV light.

Acceptance criteria 1: The chromatograms show principal spots at the same R_F value.

Analysis 2: Estimate the amounts of any additional spots observed in the chromatograms of the Sample solution in Analysis 1 by comparing them with the spots in the two chromatograms of Standard solution B, corresponding to 0.5% and 1.0% of impurities.

4.1.3 Acceptance criteria 2

Any individual impurities: 0.5%; no spot other than the principal spot of the Sample solution is larger or more intense than that of the principal spot of the 5-ul portion of Standard solution B.

Total impurities: NMT 2.0%

5 SPECIFIC TESTS

MELTING RANGE (741): 1970-203"

LOSS ON DRYING (731)

Analysis: Dry a sample under vacuum at 100 for 4 h.

Acceptance criteria: NMT 0.5%

6 ADDITIONAL REQUIREMENTS

PACKAGING AND STORAGE: Preserve in well-closed containers.

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

USP REFERENCE STANDARDS (11)

USP Clorsulon RS