Cefdinir

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

1 DEFINITION

Cefdinir contains NLT 940 µg/mg and NMT 1030 µg/mg of cefdinir (C₁₄H₁₃N₅O₅S₂), calculated on the anhydrous basis.

2 IDENTIFICATION

A. SPECTROSCOPIC IDENTIFICATION TESTS 〈197〉 , Infrared Spectroscopy : 197M

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

Solution A: 14.2 g/L of anhydrous dibasic sodium phosphate Solution B: 13.6 g/L of monobasic potassium phosphate

Solution C: Dilute tetramethylammonium hydroxide (10%) with water to obtain a 0.1% solution. Adjust with 10% phosphoric acid to a pH of 5.5.

Solution D: 37.2 mg/mL of edetate disodium

Buffer: Combine appropriate amounts of Solution A and Solution B (about 2:1) to obtain a solution with a pH of 7.0. Mobile phase: Acetonitrile, methanol, Solution C, and Solution D (300:200:4500:2)

System suitability solution: 0.2 mg/mL of USP Cefdinir RS and 0.5 mg/mL of USP Cefdinir Related Compound A RS in Buffer Standard solution: 0.2 mg/mL of USP Cefdinir RS in Buffer

Sample solution: 0.2 mg/mL of Cefdinir in Buffer

3.1.1 Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 254 nm

Column: 4.6-mm × 15-cm; 5-µm packing L1 Column temperature: 40°

Flow rate: 1 mL/min

Injection size: 5 µL System suitability

Samples: System suitability solution and Standard solution. USP Cefdinir Related Compound A RS should produce four peaks.

Tailing factor: NMT 1.5 for cefdinir, System suitability solution

Resolution: NLT 1.2 between the second peak of cefdinir related compound A and cefdinir, System suitability solution Relative standard deviation: NMT 1.0%, Standard solution

3.1.2 Analysis

Samples: Standard solution and Sample solution

Calculate the quantity, in µg/mg, of cefdinir (C H N O S ) in the portion of Cefdinir taken:

Result = (r_u/r_s) × (C_s/C_u) × P

r_u = peak response from the Sample solution

r_s = peak response from the Standard solution

C_s = concentration of the Standard solution (mg/mL)

C_u = concentration of the Sample solution (mg/mL)

P = purity of USP Cefdinir RS (µg/mg)

Acceptance criteria: 940–1030 µg/mg on the anhydrous basis

4 IMPURITIES

RESIDUE ON IGNITION 〈281〉: NMT 0.20%

Change to read:

ORGANIC IMPURITIES

Solution A, Solution B, Solution C, Solution D, and Buffer: Prepare as directed in the Assay. Solution E: To 1000 mL of Solution C add 0.4 mL of Solution D.

Solution F: Acetonitrile, methanol, Solution C, and Solution D (300:200:500:0.4) Mobile phase: See Table 1.