Cefixime 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

Cefixime Tablets contain the equivalent of NLT 90.0% and NMT 110.0% of the labeled amount of cefixime (C₁₆H₁₅N₅O₇S₂).

2 IDENTIFICATION

A. 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: 25 mL of 0.4 M tetrabutylammonium hydroxide solution diluted with water to 1000 mL, and adjusted with 1.5 M phosphoric acid to a pH of 6.5

Solution B: 13.6 g/L of monobasic potassium phosphate in water Solution C: 14.2 g/L of anhydrous dibasic sodium phosphate in water Buffer: Adjust an aliquot of Solution C with Solution B to a pH of 7.0. Mobile phase: Acetonitrile and Solution A (1:3)

System suitability solution: 1 mg/mL of USP Cefixime RS in water. Heat this solution at 95° in an oil bath for 45 min, cool, and use promptly.

Standard solution: 0.2 mg/mL of USP Cefixime RS in Buffer. Use this solution promptly.

Sample stock solution: Nominally 4 mg/mL of cefixime in Buffer from finely powdered Tablets (NLT 20). Sonicate as required, and centrifuge. Sample solution: Nominally 0.2 mg/mL of cefixime from Sample stock solution in Buffer

3.1.1 Chromatographic system

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

Detector: UV 254 nm

Column: 4.6-mm × 12.5-cm; 4-µm packing L1 Column temperature: 40°

Flow rate: Adjusted so that the retention time of cefixime is about 10 min

Injection volume: 10 µL

3.1.2 System suitability

Samples: System suitability solution and Standard solution

[NOTE—The relative retention times for cefixime (E)-isomer and cefixime are about 0.9 and 1.0, respectively.] Suitability requirements

Resolution: NLT 2.0 between cefixime and cefixime (E)-isomer, System suitability solution Column efficiency: NLT 4000 theoretical plates for the Standard solution

Calculate as follows:

Result = 5.545(t/W_h/2)²

t = retention time

W_h/2 = peak width at half height

Tailing factor: NLT 0.9 and NMT 2.0 for the analyte peak Calculate as follows:

Result = W_0.1/2f

W_0.1 = width of peak of 10% height

f = distance from the peak maximum to the leading edge of the peak measured at 10% of the peak height

Relative standard deviation: NMT 2.0%, Standard solution Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of cefixime (C₁₆H₁₅N₅O₇S₂) in the portion of Tablets taken:

Result = (r_u/r_s) × (C_s/C_u) × P × 100

r_u = peak response from the Sample solution

r_s = peak response from the Standard solution

C_s = concentration of USP Cefixime RS in the Standard solution (mg/mL)

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

P = potency of cefixime in USP Cefixime RS (mg/mg) Acceptance criteria: 90.0%–110.0%

4 PERFORMANCE TESTS

4.1 DISSOLUTION 〈711〉

Medium: 6.8 g/L of monobasic potassium phosphate in water, adjusted with 1 N sodium hydroxide to a pH of 7.2; 900 mL Apparatus 1: 100 rpm

Time: 45 min

Detector: UV 288 nm

Standard solution: USP Cefixime RS in Medium. An amount of methanol not to exceed 0.1% of the total volume of the Standard solution may be used to bring the USP Cefixime RS into solution before dilution with Medium, and the solution may be sonicated to ensure complete dissolution of the USP Cefixime RS.

Sample solution: Sample per Dissolution 〈711〉. Dilute with Medium to a concentration similar to that of the Standard solution. Tolerances: NLT 75% (Q )

4.2 UNIFORMITY OF DOSAGE UNITS 〈905〉

Meet the requirements

5 SPECIFIC TESTS

WATER DETERMINATION, Method I〈921〉: NMT 10.0%

6 ADDITIONAL REQUIREMENTS

PACKAGING AND STORAGE: Preserve in tight containers.

LABELING: Label the Tablets to indicate that the cefixime contained therein is in the trihydrate form.

USP REFERENCE STANDARDS 〈11〉

USP Cefixime RS