Cefadroxil 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

Cefadroxil Tablets contain NLT 90.0% and NMT 120.0% of the labeled amount of cefadroxil (C₁₆H₁₇N₃O₅S).

1.1 IDENTIFICATION

A. Thin-Layer Chromatography

Standard solution: 2 mg/mL of USP Cefadroxil RS

Sample solution: Nominally 2 mg/mL of cefadroxil from powdered Tablets dissolved in water and filtered

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Adsorbent: 0.25-mm layer of binder-free silica gel

Application volume: 20 μL

Pre-developing solvent solution: n-Hexane and tetradecane (95:5)

Solution A: 66.7-mg/mL solution of ninhydrin in acetone

Developing solvent system: 0.1 M citric acid, 0.1 M dibasic sodium phosphate, and Solution A (60:40:1.5)

Spray reagent: 2-mg/mL solution of ninhydrin in dehydrated alcohol. Protect from light.

Analysis

Samples: Standard solution and Sample solution

Place the thin-layer chromatographic plate in a chamber containing the Pre-developing solvent solution to a depth of about 1 cm, and allow the solvent front to move the length of the plate. Remove the plate from the chamber, and allow the solvent to evaporate. Apply the Sample solution and Standard solution to the plate, allow the spots to dry, and develop the chromatogram in the Developing solvent system until the solvent front has moved three-fourths of the length of the plate. Remove the plate from the developing chamber, mark the solvent front, and allow to air-dry. Spray the plate with the Spray reagent, dry for 10 min at 110°, and examine the chromatogram.

Acceptance criteria: The R value of the principal spot of the Sample solution corresponds to that of the Standard solution.

2 ASSAY

Procedure

Buffer: 6.8 g/L of monobasic potassium phosphate in water, adjusted with 10 N potassium hydroxide to a pH of 5.0

Mobile phase: Acetonitrile and Buffer (40:960)

Standard solution: 1.06 mg/mL of USP Cefadroxil RS in Buffer. This solution contains nominally 1 mg/mL of cefadroxil. Use this solution on the day prepared.

Sample solution: Nominally 1 mg/mL of cefadroxil from finely powdered Tablets (NLT 10) in Buffer. Stir by mechanical means for 5 min. Use this solution on the day prepared.

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 230 nm

Column: 4-mm × 25-cm; packing L1

Flow rate: 1.5 mL/min

Injection volume: 10 μL

System suitability

Sample: Standard solution

Suitability requirements

Capacity factor, k′: 2.0–3.5

Column efficiency: NLT 1800 theoretical plates

Tailing factor: NMT 2.2

Relative standard deviation: NMT 2.0%

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of cefadroxil (C₁₆H₁₇N₃O₅S) in the portion of Tablets taken:

Result = (r_U/r_S) x (C_S/C_U) × P × F × 100

r_U = peak response from the Sample solution

r_S = peak response from the Standard solution

C_S = concentration of USP Cefadroxil RS in the Standard solution (mg/mL)

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

P = potency of cefadroxil in USP Cefadroxil RS (μg/mg)

F = conversion factor, 0.001 mg/μg

Acceptance criteria: 90.0%–120.0%

3 PERFORMANCE TESTS

Dissolution 〈711〉

Medium: Water; 900 mL

Apparatus 2: 50 rpm

Time: 30 min

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

Sample solution: Sample per 〈711〉. Pass a portion of the solution under test through a suitable filter, and dilute with water if necessary.

Instrumental conditions

Mode: UV

Analytical wavelength: 263 nm

Analysis

Samples: Standard solution and Sample solution

Tolerances: NLT 75% (Q) of the labeled amount of cefadroxil (C₁₆H₁₇N₃O₅S) is dissolved.

Uniformity of Dosage Units 〈905〉: Meet the requirements

4 SPECIFIC TESTS

Water Determination, Method I〈921〉: NMT 8.0%

5 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in tight containers.

Labeling: The Tablets prepared using the hemihydrate form of cefadroxil are so labeled.

USP Reference Standards 〈11〉

USP Cefadroxil RS