Amoxicillin 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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Amoxicillin Tablets

1 DEFINITION

Amoxicillin Tablets contain 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:

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:

Place NLT 5 Tablets in a high-speed glass blender jar containing Buffer sufficient to yield a concentration of 1 mg/mL of anhydrous amoxicillin. Blend for 4 ± 1 min, allow to stand for 5 min, and centrifuge a portion of the mixture.

[Note—Where the volume of Buffer required would exceed 500 mL, place 5 Tablets in a volumetric flask of such capacity that when finally diluted to volume, a concentration of 1 mg of anhydrous amoxicillin per milliliter would be obtained. Add a volume of Buffer equivalent to three-fourths of the capacity of the volumetric flask, and sonicate for 5 min. Dilute with Buffer to volume, add a magnetic stirring bar, and stir for 30 min. Centrifuge a portion of this solution.]

Pass a portion of the clear supernatant through a suitable filter.

[Note—Use this solution within 6 h.]

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%

Analysis

Samples: Standard solution and Sample solution

Calculation:

Percentage of the labeled amount of amoxicillin (C₁₆H₁₉N₃O₅S) in the portion of Tablets taken:

Result = (rᵤ / rₛ) × (Cₛ / Cᵤ) × P × F × 100

Where:

rᵤ = peak response of amoxicillin from the Sample solution

rₛ = peak response of amoxicillin from the Standard solution

Cₛ = concentration of USP Amoxicillin RS in the Standard solution (mg/mL)

Cᵤ = 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〉

Medium: Water; 900 mL

Apparatus 2: 75 rpm

Time: 30 min

Determine the amount of amoxicillin (C₁₆H₁₉N₃O₅S) dissolved using the following method.

Buffer:

27.2 g monobasic potassium phosphate in 3 L water. Adjust with 45% potassium hydroxide TS to pH 5.0 ± 0.1. Dilute with water to obtain 4 L.

Mobile phase:

Acetonitrile and Buffer (1:39)

Standard solution:

0.05 mg/mL USP Amoxicillin RS in Buffer.

[Note—Use within 6 h.]

Sample solution:

Filter through a 0.5-µm filter. Dilute with water to obtain approx. 0.045 mg/mL amoxicillin.

Use within 6 h.

Chromatographic system

Mode: LC

Detector: UV 230 nm

Columns:

Guard: 2-mm × 2-cm; packing L2

Analytical: 3.9-mm × 30-cm; packing L1

Column temperature: 40 ± 1°

Flow rate: 0.7 mL/min

Injection volume: 10 µL

System suitability

Sample: Standard solution

Requirements:

Tailing factor: NMT 2.5

Relative standard deviation: NMT 1.5%

Analysis

Samples: Standard solution and Sample solution

Calculate percentage dissolved:

Result = (rᵤ / rₛ) × (Cₛ / L) × V × D × P × F × 100

Where:

rᵤ = peak response of amoxicillin from Sample solution

rₛ = peak response from Standard solution

Cₛ = concentration of USP Amoxicillin RS (mg/mL)

L = label claim (mg/Tablet)

V = volume of dissolution medium, 900 mL

D = dilution factor

P = potency (µg/mg)

F = 0.001 mg/µg

Tolerances:

NLT 75% (Q) of labeled amount (C₁₆H₁₉N₃O₅S) dissolved.

Chewable Tablets (200 or 400 mg):

Time: 20 min

Tolerance: NLT 70% (Q)

Chewable Tablets (125 or 250 mg):

Time: 90 min

Tolerance: NLT 70% (Q)

Veterinary products:

Same method; Apparatus 2 at 100 rpm.

Delete the following:

(RB 1-Nov-2021)

5 SPECIFIC TESTS

Microbial Enumeration Tests 〈61〉 and Tests for Specified Microorganisms 〈62〉:

Total aerobic microbial count ≤ 10³ cfu/g

Total combined molds and yeasts ≤ 10² cfu/g.

6 ADDITIONAL REQUIREMENTS

Packaging and Storage:

Preserve in tight containers; store at controlled room temperature.

Labeling:

Label chewable Tablets to indicate they are to be chewed before swallowing.

Tablets intended solely for veterinary use are so labeled.

USP Reference Standards 〈11〉

USP Amoxicillin RS

(RB 1-Nov-2021)