Penicillin G Potassium for Oral Solution

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

Penicillin G Potassium for Oral Solution is a dry mixture of Penicillin G Potassium and one or more suitable buffers, colors, diluents, avors, and preservatives. It contains NLT 90.0% and NMT 130.0% of the labeled number of Penicillin G Units when constituted as directed in the labeling.

2 IDENTIFICATION

A. Thin-Layer Chromatography

Solution A: Acetone, 0.1 M citric acid, and 0.1 M sodium citrate (2:1:1)

Standard solution: Prepare a solution containing the equivalent of 12,000 Penicillin G Units/mL from USP Penicillin G Potassium RS in Solution A

Sample solution: Shake a portion of it, containing nominally 100,000 Penicillin G Units, with 8 mL of Solution A

Chromatographic system

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

Adsorbent: 0.25-mm layer of chromatographic silica gel mixture

Application volume: 20 μL

Developing solvent system: Toluene, dioxane, and glacial acetic acid (90:25:4)

Spray reagent 1: Starch TS

Spray reagent 2: Iodine TS diluted 1 in 10 with water

Analysis

Samples: Standard solution and Sample solution

Place the plate in a suitable chromatographic chamber. Develop the chromatogram in the Developing solvent system until the solvent front has moved three-fourths of the length of the plate. Remove the plate from the chamber, mark the solvent front, and allow to air-dry. Spray the plate with Spray reagent 1 followed by Spray reagent 2. Penicillin G appears as a white spot on a purple background.

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

3 ASSAY

Procedure

Standard solution: Prepare as directed in Iodometric Assay - Antibiotics 〈425〉, Standard Preparation, using USP Penicillin G Potassium RS.

Sample solution: Constitute Penicillin G Potassium for Oral Solution as directed in the labeling using Buffer B.1 (see Antibiotics - Microbial Assay 〈81〉, Media and Solutions, Solutions). Dilute a suitable aliquot to obtain a solution containing nominally 2000 Penicillin G Units/mL.

Analysis

Samples: Standard solution and Sample solution Pipet 2 mL of the Sample solution into each of two glass-stoppered, 125-mL conical flasks. Proceed as directed in Iodometric Assay - Antibiotics 〈425〉, Procedure, using one of the flasks to perform the Blank Determination.

Calculate the percentage of the labeled number of Penicillin G Units in the portion of Penicillin G Potassium for Oral Solution taken:

Result = (B − I) × F × [1/(D × V)] × 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 = equivalency factor as calculated in the chapter (Penicillin G Unit/mL of 0.01 N sodium thiosulfate consumed by the Standard solution)

D = nominal concentration of penicillin G in the Sample solution (Penicillin G Units/mL)

V = volume of Sample solution used for the Inactivation and Titration (mL)

Acceptance criteria: 90.0%–130.0%

4 PERFORMANCE TESTS

Uniformity of Dosage Units 〈905〉

For solids packaged in single-unit containers: Meets the requirements

Deliverable Volume 〈698〉: Meets the requirements

5 SPECIFIC TESTS

pH 〈791〉

Sample solution: Constitute as directed in the labeling.

Acceptance criteria: 5.5–7.5

Water Determination 〈921〉, Method I: NMT 1.0%

6 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in tight containers.

USP Reference Standards 〈11〉

USP Penicillin G Potassium RS