Ampicillin for Oral Suspension

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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Ampicillin for Oral Suspension

1 DEFINITION

Ampicillin for Oral Suspension contains an amount of Ampicillin (anhydrous or as the trihydrate) equivalent to NLT 90.0% and NMT 120.0% of the labeled amount of ampicillin (C₁₆H₁₉N₃O₄S), when constituted as directed. It contains one or more suitable buffers, colors, flavors, preservatives, and sweetening ingredients.

2 IDENTIFICATION

A. Thin-Layer Chromatography

Diluent: Acetone and 0.1 N hydrochloric acid (4:1)

Standard solution: 5 mg/mL of USP Ampicillin RS in Diluent

Sample solution: Nominally 5 mg/mL of ampicillin in Diluent

Chromatographic system

(See Chromatography 〈621〉, Thin-Layer Chromatography.)

Mode: TLC

Adsorbent: 0.25-mm layer of chromatographic silica gel mixture

Application volume: 2 µL

Developing solvent system: Acetone, toluene, glacial acetic acid, and water (650:100:25:100)

Spray reagent: 3 mg/mL of ninhydrin in alcohol

Analysis

Samples: Standard solution and Sample solution

Apply the Standard solution and the Sample solution to the plate, and develop the chromatogram in the Developing solvent system. When the solvent front has moved about three-fourths of the length of the plate, remove the plate from the chamber, mark the solvent front, and allow to air-dry. Locate the spots on the plate by spraying lightly with Spray reagent, and dry at 90° for 15 min.

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

3 ASSAY

Procedure

Standard solution: Prepare as directed for Standard preparation in Iodometric Assay—Antibiotics 〈425〉, using USP Ampicillin RS.

Sample solution: Nominally 1.25 mg/mL of ampicillin prepared as follows. Dilute a suitable aliquot of Ampicillin for Oral Suspension, constituted as directed in the labeling, freshly mixed and free from air bubbles, with water.

Analysis: Proceed as directed for Iodometric Assay—Antibiotics 〈425〉, Procedure.

Calculate the percentage of the labeled amount of ampicillin (C₁₆H₁₉N₃O₄S) in the portion of Ampicillin for Oral Suspension taken:

Result = (B − I) × F × (1/Cₛ) × 100

B = volume of 0.01 N sodium thiosulfate consumed in the Blank Determination (mL)

I = volume of 0.01 N sodium thiosulfate consumed in the Inactivation and Titration (mL)

F = factor as calculated in Iodometric Assay—Antibiotics 〈425〉

Cₛ = nominal concentration of ampicillin in the Sample solution (mg/ml)

Acceptance criteria: 90.0%–120.0%

4 PERFORMANCE TESTS

Deliverable Volume 〈698〉: Meets the requirements

Uniformity of Dosage Units 〈905〉

For single-unit containers

Acceptance criteria: Meets the requirements

5 SPECIFIC TESTS

pH 〈791〉

Sample solution: Constitute as directed in the labeling.

Acceptance criteria: 5.0–7.5

Water Determination, Method I〈921〉:

NMT 2.5% where the solid for Oral Suspension contains anhydrous ampicillin or NMT 5.0% if it contains ampicillin trihydrate and the equivalent of 100 mg/mL of ampicillin when constituted as directed in the labeling

6 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in tight containers.

Labeling: Label to indicate whether the ampicillin therein is in the anhydrous form or is the trihydrate.

USP Reference Standards 〈11〉

USP Ampicillin RS