Sulfaquinoxaline Oral Solution

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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Sulfaquinoxaline Oral Solution contains the equivalent of not less than 90.0 percent and not more than 110.0 percent of the labeled concentration of sulfaquinoxaline (C₁₄H₁₂N₄O₂S).

Packaging and storage—Preserve in tight, light-resistant containers.

Labeling—Label it to indicate that it is for veterinary use only.

USP REFERENCE STANDARDS 〈11〉—

USP Sulfaquinoxaline RS

Identification—The retention time of the major peak in the chromatogram of the Assay preparation corresponds to that in the chromatogram of the Standard preparation, as obtained in the Assay.

DELIVERABLE VOLUME 〈698〉: meets the requirements.

PH 〈791〉: not less than 12.

Assay—

Mobile phase and Chromatographic system—Proceed as directed in the Assay under Sulfaquinoxaline.

Standard preparation—Dissolve an accurately weighed quantity of USP Sulfaquinoxaline RS in 0.01 N sodium hydroxide to obtain a solution having a known concentration of about 0.7 mg per mL. Dilute an accurately measured volume of this solution quantitatively with water to obtain a solution having a known concentration of about 0.15 mg per mL.

Assay preparation—Transfer an accurately measured volume of Oral Solution, equivalent to about 300 mg of sulfaquinoxaline, to a 2000-mL volumetric flask, dilute with water to volume, and mix.

Procedure—Separately inject equal volumes (about 8 µL) of the Standard preparation and the Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity, in mg, of sulfaquinoxaline (C₁₄H₁₂N₄O₂S) in each mL of the Oral Solution taken by the formula:

2000(C/V)(r_U/r_S)

in which C is the concentration, in mg per mL, of USP Sulfaquinoxaline RS in the Standard preparation, V is the volume, in mL, of Oral Solution taken to prepare the Assay preparation, and r_U and r_S are the sulfaquinoxaline peak responses obtained from the Assay preparation and the Standard preparation, respectively.