Amoxicillin 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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Amoxicillin Oral Suspension is a suspension of Amoxicillin in Soybean Oil. It contains not less than 90.0 percent and not more than 120.0 percent of the labeled amount of amoxicillin (C₁₆H₁₉N₃O₅S).

Packaging and storage-Preserve in multiple-dose containers equipped with a suitable dosing pump.

Labeling-Label it to indicate that it is for veterinary use only.

USP REFERENCE STANDARDS (11).-

USP Amoxicillin RS

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Identification-Prepare a test solution by shaking a portion of Oral Suspension with a mixture of acetone and 0.1 N hydrochloric acid (4:1) to obtain a solution containing about 1 mg of amoxicillin per mL. Prepare a Standard solution of USP Amoxicillin RS in 0.1 N hydrochloric acid containing 1 mg per mL. Use within 10 minutes after preparation. Apply separately 5 µL of each solution on a thin-layer chromatographic plate coated with a 0.25-mm layer of chromatographic silica gel mixture (see Chromatography (621)). Place the plate in a suitable chromatographic chamber, and develop the chromatogram in a solvent system consisting of a mixture of methanol, chloroform, water, and pyridine (90:80:30:10). When the solvent front has moved about three-fourths of the length of the plate, remove the plate from the chamber, and dry with warm air for 10 minutes. Locate the spots on the plate by spraying lightly with a solution of ninhydrin in alcohol containing 3 mg per mL, and dry at 110° for 15 minutes: the R, value of the principal spot obtained from the test solution corresponds to that obtained from the Standard solution. _{(ERR 1-Feb-2024)}

WATER DETERMINATION, Method / (921): not more than 2.0%, 20 mL of a mixture of toluene and methanol (7:3) being used in place of methanol in the titration vessel.

Assay-

Standard preparation-Prepare as directed for Standard Preparation under lodometric Assay-Antibiotics (425), using USP Amoxicillin RS.

Assay preparation-Using the dosing pump, deliver a number of doses of Oral Suspension, equivalent to about 250 mg of amoxicillin, to a separator containing 100 mL of hexanes, and shake vigorously. Add 140 mL of water, and shake for 5 minutes. Allow the layers to separate, and drain the lower, aqueous layer into a 250-mL volumetric flask. Repeat the extraction with two 50-mL portions of water. Combine the aqueous extracts in the volumetric flask, dilute with water to volume, and mix.

Procedure-Proceed with Oral Suspension as directed for Procedure under lodometric Assay-Antibiotics (425), using USP Amoxicillin RS. Calculate the quantity, in mg, of amoxicillin (C₁₆H₁₉N₃O₅S) in each dose of Oral Suspension taken by the formula:

(250/N)(F/2000)(B-1)

in which N is the number of doses taken, and the other terms are as defined therein.