Penicillin G Potassium for Injection

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 Injection is sterile Penicillin G Potassium or a sterile, dry mixture of Penicillin G Potassium with NLT 4.0% and NMT 5.0% of Sodium Citrate, of which NMT 0.15% may be replaced by Citric Acid. It has a potency of NLT 90.0% and NMT 120.0% of the labeled number of Penicillin G Units. In addition, where it contains Sodium Citrate it has a potency of NLT 1335 and NMT 1595 Penicillin G Units/mg.

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: Nominally 12,000 Penicillin G Units/mL from Penicillin G Potassium for Injection in 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

Solution A: 0.01 M monobasic potassium phosphate

Mobile phase: Methanol and Solution A (40:60)

System suitability solution: 0.1 mg/mL each of USP Penicillin G Potassium RS and 2-phenylacetamide in water

Standard solution: 0.1 mg/mL of USP Penicillin G Potassium RS in water. This solution contains about 160 Penicillin G Units/mL. Shake as needed to dissolve.

Sample solution 1 (where it is represented as being in a single-dose container): Constitute Penicillin G Potassium for Injection as directed in the labeling. Withdraw all of the withdrawable contents, using a hypodermic needle and syringe, and dilute with water to obtain a solution containing nominally 160 Penicillin G Units/mL.

Sample solution 2 (where the label states the quantity of penicillin G in a given volume of constituted solution): Constitute Penicillin G Potassium for Injection as directed in the labeling. Dilute a suitable aliquot of the constituted solution with water to obtain a solution containing nominally 160 Penicillin G Units/mL.

Sample solution 3 (where it contains sodium citrate): Transfer about 50 mg of the Penicillin G Potassium for Injection to a 500-mL volumetric flask. Add 400 mL of water, and shake to dissolve. Dilute with water to volume.

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 220 nm

Column: 4.6-mm × 10-cm; 5-μm packing L1

Flow rate: 1 mL/min

Injection volume: 10 μL

System suitability

Samples: System suitability solution and Standard solution

[Note - The relative retention times for 2-phenylacetamide and penicillin G are about 0.8 and 1.0, respectively.]

Suitability requirements

Resolution: NLT 2.0 between 2-phenylacetamide and penicillin G, System suitability solution

Column efficiency: NLT 1000 theoretical plates, Standard solution

Tailing factor: NMT 2.0, Standard solution

Relative standard deviation: NMT 2.0%, Standard solution

Analysis

Samples: Standard solution and Sample solution 1, Sample solution 2, or Sample solution 3

Perform the Assay on 10 containers where it is represented as being in a single-dose container and, if necessary, on 10 containers where the label states the quantity of penicillin G in a given volume of constituted solution. Use the individual results to determine the Uniformity of Dosage Units and the average of the results as the Assay value.

Calculate the percentage of the labeled number of Penicillin G Units in the container or in the portion of constituted solution taken:

Result = (r_U/r_S) × (C_S/C_U) × P × 100

r_U = peak response from Sample solution 1 or Sample solution 2

r_S = peak response from the Standard solution

C_S = concentration of USP Penicillin G Potassium RS in the Standard solution (mg/mL)

C_U = nominal concentration of Sample solution 1 or Sample solution 2 (Penicillin G Units/mL)

P = potency of penicillin G in USP Penicillin G Potassium RS (Penicillin G Units/mg)

Calculate the potency, in Penicillin G Units/mg, of the Penicillin G Potassium for Injection taken:

Result = (r_U/r_S) × (C_S/C_U) × P

r_U = peak response from Sample solution 3

r_S = peak response from the Standard solution

C_S = concentration of USP Penicillin G Potassium RS in the Standard solution (mg/mL)

C_U = concentration of Penicillin G Potassium for Injection in Sample solution 3 (mg/mL)

P = potency of penicillin G in USP Penicillin G Potassium RS (Penicillin G Units/mg)

Acceptance criteria: 90.0%–120.0% of the labeled number of Penicillin G Units. Where Penicillin G Potassium for Injection contains sodium citrate it has a potency of NLT 1335 and NMT 1595 Penicillin G Units/mg.

4 PERFORMANCE TESTS

Uniformity of Dosage Units 〈905〉: Meets the requirements. Perform the Assay on 10 containers where it is represented as being in a single-dose container and, if necessary, on 10 containers where the label states the quantity of penicillin G in a given volume of constituted solution. Use the individual results to determine the Uniformity of Dosage Units and the average of the results as the Assay value.

5 SPECIFIC TESTS

Injections and Implanted Drug Products 〈1〉, Specific Tests, Completeness and clarity of solutions: At the time of use, it meets the requirements.

Bacterial Endotoxins Test 〈85〉: It contains NMT 0.01 USP Endotoxin Units/100 Penicillin G Units.

Sterility Tests 〈71〉: It meets the requirements when tested as directed in Test for Sterility of the Product to Be Examined, Membrane Filtration.

Crystallinity 〈695〉: Meets the requirements

pH 〈791〉

Sample solution: A solution containing 60 mg/mL. Where packaged for dispensing, use the solution constituted as directed in the labeling.

Acceptance criteria: 5.0–7.5. Where it is labeled as containing sodium citrate, the pH is between 6.0 and 8.5.

Loss on Drying 〈731〉

Sample: 100 mg of Penicillin G Potassium for Injection

Analysis: Dry the Sample in a capillary-stoppered bottle under vacuum at 60° for 3 h.

Acceptance criteria: NMT 1.5%

Particulate Matter in Injections 〈788〉: Meets the requirements for small-volume injections

Other Requirements: It meets the requirements in Labeling 〈7〉, Labels and Labeling for Injectable Products.

6 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve as described in Packaging and Storage Requirements 〈659〉, Injection Packaging, Packaging for constitution.

USP Reference Standards 〈11〉

USP Penicillin G Potassium RS