Amoxicillin 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

Amoxicillin Capsules contain the equivalent of NLT 90.0% and NMT 120.0% of the labeled amount of amoxicillin (C₁₆H₁₉N₃O₅S).

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

Procedure

Buffer: Dissolve 6.8 g/L of monobasic potassium phosphate in water. Adjust with 45% potassium hydroxide TS to a pH of 5.0 ± 0.1. Mobile phase: Acetonitrile and Buffer (1:24)

Standard solution: 1.2 mg/mL of USP Amoxicillin RS in Buffer. [Note—Use this solution within 6 h.]

Sample solution: Remove, as completely as possible, the contents of NLT 20 Capsules. Mix the combined contents, and transfer a quantity, equivalent to 200 mg of anhydrous amoxicillin, to a 200-mL volumetric flask. Add Buffer to volume. Sonicate if necessary to ensure complete dissolution. [Note—Use this solution within 6 h.]

3.1 Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 230 nm

Column: 4-mm × 25-cm; 10-µm packing L1

Flow rate: 1.5 mL/min

Injection volume: 10 µL

System suitability

Sample: Standard solution

Suitability requirements

Tailing factor: NMT 2.5

Relative standard deviation: NMT 2.0%

3.2 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of amoxicillin (C₁₆H₁₉N₃O₅S) in the portion of Capsules taken:

Result = (r_U /r_S) × (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 Amoxicillin RS in the Standard solution (mg/mL)

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

P = potency of amoxicillin in USP Amoxicillin RS (µg/mg)

F = conversion factor, 0.001 mg/µg

Acceptance criteria: 90.0%–120.0%

4 PERFORMANCE TESTS

Dissolution 〈711〉

Test 1

Medium: Water; 900 mL

Apparatus 1: 100 rpm, for Capsules containing 250 mg

Apparatus 2: 75 rpm, for Capsules containing 500 mg

Time: 60 min

Analytical wavelength: UV 272 nm

Standard solution: USP Amoxicillin RS in Medium

Sample solution: Pass a portion of the solution under test through a suitable filter. Dilute with Medium, if necessary, to a concentration that is similar to that of the Standard solution.

Tolerances: NLT 80% (Q) of the labeled amount of amoxicillin (C₁₆H₁₉N₃O₅S) is dissolved.

Test 2: If the product complies with this test, the labeling indicates that it meets USP Dissolution Test 2.

Medium: Water; 900 mL

Apparatus 1: 100 rpm

Time: 90 min

Analytical wavelength: UV 272 nm

Standard solution: USP Amoxicillin RS in Medium

Sample solution: Pass a portion of the solution under test through a suitable filter. Dilute with Medium, if necessary, to a concentration that is similar to that of the Standard solution.

Tolerances: NLT 80% (Q) of the labeled amount of amoxicillin (C₁₆H₁₉N₃O₅S) is dissolved.

Uniformity of Dosage Units 〈905〉: Meet the requirements

Delete the following:

(RB 1-Nov-2021)

5 SPECIFIC TESTS

Microbial Enumeration Tests 〈61〉 and Tests for Specified Microorganisms 〈62〉: The total aerobic microbial count does not exceed 103 cfu/g, and the total combined molds and yeasts count does not exceed 102 cfu/g.

6 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in tight containers, and store at controlled room temperature.

Labeling: When more than one Dissolution test is given, the labeling states the Dissolution test used only if Test 1 is not used. Change to read:

USP Reference Standards 〈11〉

USP Amoxicillin RS

(RB 1-Nov-2021)