Sulfamethizole Tablets

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

Sulfamethizole Tablets contain NLT 95.0% and NMT 105.0% of the labeled amount of sulfamethizole.

2 IDENTIFICATION

Change to read:

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

Sample: Equivalent to 500 mg of sulfamethizole from finely powdered Tablets

Analysis: Triturate the Sample with 5 mL of chloroform, and transfer to a small filter. Wash with another 5-mL portion of chloroform, and discard the filtrate. Triturate the residue with 10 mL of 6 N ammonium hydroxide for 5 min, add 10 mL of water, and filter. Warm the filtrate until most of the ammonia is expelled, cool, and add 6 N acetic acid until the mixture is distinctly acid. A precipitate of sulfamethizole is formed. Collect the precipitate on a filter, wash it well with cold water, and dry at 105° for 2 h.

Acceptance criteria: The infrared spectrum of the residue matches the infrared spectrum of similarly prepared USP Sulfamethizole RS.

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

Procedure

Mobile phase: Methanol, glacial acetic acid, and water (30:1:69)

Standard stock solution: 0.4 mg/mL of USP Sulfamethizole RS in methanol

Standard solution: 8 μg/mL of USP Sulfamethizole RS from the Standard stock solution in Mobile phase

Sample stock solution: Nominally 0.4 mg/mL of sulfamethizole prepared as follows. Transfer an equivalent to 40 mg of sulfamethizole from NLT 20 finely powdered Tablets to a 250-mL screw-capped bottle. Add 100.0 mL of methanol to the bottle, cap the bottle, shake by mechanical means for 30 min, and filter.

Sample solution: 8 μg/mL of sulfamethizole from the Sample stock solution in Mobile phase

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 254 nm

Column: 3.9-mm × 30-cm; 10-μm packing L1

Flow rate: 1 mL/min

Injection volume: 50 μL

System suitability

Sample: Standard solution

Suitability requirements

Column efficiency: NLT 2000 theoretical plates

Tailing factor: NMT 2.0

Relative standard deviation: NMT 2.0%

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of sulfamethizole in the portion of Tablets taken:

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

r_U = peak response from the Sample solution

r_S= peak response from the Standard solution

C_S = concentration of USP Sulfamethizole RS in the Standard solution (μg/mL)

C_U = nominal concentration of sulfamethizole in the Sample solution (μg/mL)

Acceptance criteria: 95.0%–105.0%

4 PERFORMANCE TESTS

Dissolution 〈711〉

Medium: 0.01 N hydrochloric acid; 900 mL

Apparatus 2: 50 rpm

Time: 30 min

Standard solution: Prepare a solution having a known concentration of USP Sulfamethizole RS in Medium.

Sample solution: A filtered portion of the solution under test, suitably diluted with Medium

Instrumental conditions

(See Ultraviolet-Visible Spectroscopy 〈857〉.)

Mode: UV

Analytical wavelength: Absorption maximum at about 267 nm

Analysis: Calculate the percentage of the labeled amount of sulfamethizole dissolved.

Tolerances: NLT 75% (Q) of the labeled amount of sulfamethizole is dissolved.

Uniformity of Dosage Units 〈905〉: Meet the requirements

5 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in well-closed containers.

USP Reference Standards 〈11〉

USP Sulfamethizole RS