Ampicillin Soluble Powder

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 Soluble Powder

Ampicillin Soluble Powder is a dry mixture of Ampicillin (as the trihydrate) and one or more suitable diluents and stabilizing agents. It contains not less than 90.0 percent and not more than 120.0 percent of the labeled amount of ampicillin (C₁₆H₁₉N₃O₄S).

Packaging and storage— Preserve in tight containers.

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

USP Reference standards 〈11〉—

USP Ampicillin RS

Identification— Dissolve a quantity of it in a mixture of acetone and 0.1 N hydrochloric acid (4:1) to obtain a solution containing 10 mg of ampicillin per mL: the resulting solution responds to the Identification test under Ampicillin Capsules.

pH 〈791〉: between 3.5 and 6.0, in an aqueous solution containing the equivalent of 20 mg of ampicillin per mL.

Water Determination, Method I 〈921〉: not more than 5.0%.

1 Assay

Standard preparation— Prepare as directed for Standard Preparation under Iodometric Assay—Antibiotics 〈425〉, using USP Ampicillin RS.

Assay preparation— Transfer an accurately weighed quantity of Soluble Powder, equivalent to about 125 mg of ampicillin, to a 100-mL volumetric flask, dissolve in and dilute with water to volume, and mix.

Procedure— Proceed as directed for Procedure under Iodometric Assay—Antibiotics 〈425〉. Calculate the quantity, in mg, of ampicillin (C₁₆H₁₉N₃O₄S) in the portion of Soluble Powder taken by the formula:

(F/20)(B − I).