Cefdinir Capsules

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

Cefdinir Capsules contain NLT 90.0% and NMT 110.0% of the labeled amount of cefdinir (C₁₄H₁₃N₅O₅S₂).

2 IDENTIFICATION

A. SPECTROSCOPIC IDENTIFICATION TESTS 〈197〉 , Ultraviolet-Visible Spectroscopy : 197U Buffer: Prepare as directed in the Assay.

Standard solution: 10 µg/mL of USP Cefdinir RS in Buffer

Sample solution: Equivalent to 10 µg/mL of cefdinir from Capsules in Buffer. Filter before use. Cell size: 1 cm

Blank: Use the Buffer.

Acceptance criteria: Sample solution maxima and minima occur at the same wavelengths as those in the Standard solution.

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

Buffer: 10.7 g/L of dibasic sodium phosphate and 3.4 g/L of monobasic potassium phosphate. Adjust with phosphoric acid or sodium hydroxide to a pH of 7.0 ± 0.05 before final dilution.

Solution A: 7 g/L of citric acid monohydrate. Adjust with phosphoric acid to a pH of 2.0 ± 0.05.

Mobile phase: Methanol, tetrahydrofuran, and Solution A (111:28:1000)

System suitability solution: 50 µg/mL of USP Cefdinir RS and 175 µg/mL of m-hydroxybenzoic acid in Buffer Standard solution: 50 µg/mL of USP Cefdinir RS in Buffer

Sample solution: Equivalent to 50 µg/mL of cefdinir, from Capsule contents (NLT 20), in Buffer Chromatographic system

(See Chromatography 〈621〉, System Suitability.) Mode: LC

Detector: UV 254 nm

Column: 3.9-mm × 15-cm; 4-µm packing L1

Flow rate: 1.4 mL/min

Injection volume: 15 µL System suitability

Samples: System suitability solution and Standard solution Suitability requirements

Resolution: Greater than 3.0 between cefdinir and m-hydroxybenzoic acid, System suitability solution Tailing factor: NMT 2.0 for cefdinir, System suitability solution

Relative standard deviation: NMT 1.0% for cefdinir, Standard solution Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of cefdinir (C₁₄H₁₃N₅O₅S₂) in the portion of Capsules taken:

Result = (r_u/r_s) × (C_s/C_u) × 100

r_u = peak response of cefdinir from the Sample solution

r_s = peak response of cefdinir from the Standard solution

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

C_u = nominal concentration of cefdinir in the Sample solution (µg/mL)

Acceptance criteria: 90.0%–110.0%

4 PERFORMANCE TESTS

4.1 DISSOLUTION 〈711〉

Medium: 50 mM phosphate buffer, pH 6.8; 900 mL

Apparatus 2: 50 rpm

Time: 30 min Detector: UV 290 nm

Cell length: 0.1-cm flow cell

Standard solution: 0.33 mg/mL of USP Cefdinir RS in Medium

Sample solution: Pass a portion of the solution under test through a suitable filter of 0.45-µm pore size. Dilute with Medium to a concentration of about 0.33 mg/mL of cefdinir.

Blank: Dissolve 1 empty Capsule in 100 mL of Medium, and dilute to 900 mL. Filter if necessary. Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of cefdinir (C H N O S ) dissolved:

Result = (A_u/A_s) × C_s × V × D × (1/L) × 100

A_u = absorbance of the Sample solution

A_s = absorbance of the Standard solution

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

V    = volume of Medium, 900 mL

D    = dilution factor for the Sample solution (mL/mL) L    = label claim (mg/Capsule)

Tolerances: NLT 80% (Q ) of the labeled amount of cefdinir (C₁₄H₁₃N₅O₅S₂) is dissolved.

4.2 UNIFORMITY OF DOSAGE UNITS 〈905〉

Meet the requirements

5 IMPURITIES

5.1 ORGANIC IMPURITIES

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

Buffer: Combine appropriate amounts of Solution A and Solution B (about 2:1) to obtain a solution with a pH of 7.0 ± 0.1.

Solution C: Dilute tetramethylammonium hydroxide (10% aqueous) with water to obtain a 0.1% solution. Adjust with dilute phosphoric acid (1 in 10) to a pH of 5.5 ± 0.1.

Solution D: 37.2 mg/mL of edetate disodium

Solution E: To 1000 mL of Solution C add 0.4 mL of Solution D.

Solution F: Acetonitrile, methanol, Solution C, and Solution D (150:100:250:0.2) Mobile phase: See Table 1.