Sulfadiazine 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

Sulfadiazine Tablets contain NLT 95.0% and NMT 105.0% of the labeled quantity of C₁₀H₁₀N₄O₂S.

2 IDENTIFICATION

Change to read:

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

B. Melting Range or Temperature, Class Ia 〈741〉

Sample solution: Equivalent to 100 mg/mL of sulfadiazine from finely powdered Tablets in chloroform

Analysis: Transfer the Sample solution to a small filter. Wash with 5 mL 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 reaction is distinctly acid: a precipitate of sulfadiazine is formed. Collect the precipitate on a filter, wash it with cold water, and dry at 105° for 1 h.

Acceptance criteria: The sulfadiazine melts at 250°–254°.

3 ASSAY

Procedure

Mobile phase: Acetonitrile, glacial acetic acid, and water (12:1:87)

Standard solution: 1 mg/mL of USP Sulfadiazine RS in 0.025 N sodium hydroxide

Sample solution: 1 mg/mL of sulfadiazine from powdered Tablets in 0.025 N sodium hydroxide. [Note—Weigh NLT 20 Tablets, shake the solution for 30 min, and centrifuge, if necessary.]

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 254 nm

Column: 4-mm × 30-cm; packing L1

Flow rate: 2 mL/min

Injection size: 10 μL

System suitability

Sample: Standard solution

Suitability requirements

Tailing factor: NMT 1.5 for sulfadiazine

Relative standard deviation: NMT 2.0% (five replicate injections)

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of C₁₀H₁₀N₄O₂S 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 Sulfadiazine RS in the Standard solution (mg/mL)

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

Acceptance criteria: 95.0%–105.0%

4 PERFORMANCE TESTS

Dissolution 〈711〉

Medium: 0.1 N hydrochloric acid; 900 mL

Apparatus 2: 75 rpm

Time: 90 min

Detector: UV, 242 nm

Analysis: Determine the quantity of C₁₀H₁₀N₄O₂S dissolved by using UV absorption on filtered portions of the solution under test, in comparison with a Standard solution having a known concentration of USP Sulfadiazine RS in the same medium. Use Medium as the blank and cells with a path length of 0.1 cm.

Tolerances: NLT 70% (Q) of the labeled amount of C₁₀H₁₀N₄O₂S is dissolved.

Uniformity of Dosage Units 〈905〉: Meet the requirements

5 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in well-closed, light-resistant containers.

USP Reference Standards 〈11〉

USP Sulfadiazine RS