Oxacillin 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

Oxacillin for Injection contains an amount of Oxacillin Sodium equivalent to NLT 90.0% and NMT 115.0% of the labeled amount of oxacillin (C₁₉H₁₉N₃O₅S).

2 IDENTIFICATION

A. The retention time of the major peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay.

3 ASSAY

Procedure

Solution A: 2.7 g/L of monobasic potassium phosphate

Mobile phase: Acetonitrile, methanol, and Solution A (300:100:700)

Standard solution: 0.11 mg/mL of USP Oxacillin Sodium RS. Use on the day prepared.

Sample solution 1 (where it is represented as being in a single-dose container): Nominally 0.1 mg/mL of oxacillin in water, prepared as follows. Constitute Oxacillin for Injection in a volume of water corresponding to the volume of solvent specified in the labeling. Withdraw all of the withdrawable contents using a suitable hypodermic needle and syringe, and dilute with water to obtain a solution containing nominally 0.1 mg/mL of oxacillin. Use on the day prepared.

Sample solution 2 (where the label states the quantity of oxacillin in a given volume of constituted solution): Nominally 0.1 mg/mL of oxacillin in water, prepared as follows. Constitute Oxacillin for Injection with a volume of water corresponding to the volume of solvent specified in the labeling. Dilute an accurately measured volume of the constituted solution with water to obtain a solution containing nominally 0.1 mg/mL of oxacillin. Use on the day prepared.

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 225 nm

Column: 4-mm × 30-cm; packing L11

Flow rate: 2 mL/min

Injection volume: 10 μL

System suitability

Sample: Standard solution

Suitability requirements

Column efficiency: NLT 2000 theoretical plates

Tailing factor: NMT 1.6

Relative standard deviation: NMT 2.0%

Analysis

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

Calculate the percentage of the labeled amount of oxacillin (C₁₉H₁₉N₃O₅S) in the portion of Oxacillin for Injection taken:

Result = (r_U/r_S) × (C_S/C_U) × P × F × 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 Oxacillin Sodium RS in the Standard solution (mg/mL)

C_U = nominal concentration of oxacillin in Sample solution 1 or Sample solution 2 (mg/mL)

P = potency of oxacillin in USP Oxacillin Sodium RS (μg/mg)

F = conversion factor, 0.001 mg/μg

Where the test for Uniformity of Dosage Units has been performed, report the average of the determinations as the Assay value.

Acceptance criteria: 90.0%–115.0%

4 PERFORMANCE TESTS

Uniformity of Dosage Units 〈905〉: Meets the requirements for Content Uniformity for individual containers using Sample solution 1 or Sample solution 2, or both, as appropriate, prepared as directed in the Assay.

5 SPECIFIC TESTS

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

Bacterial Endotoxins Test 〈85〉: It contains NMT 0.2 USP Endotoxin Units/mg of oxacillin.

Injections and Implanted Drug Products 〈1〉, Specific Tests, Completeness and clarity of solutions: Meets the requirements

Water Determination 〈921〉, Method I: NMT 6.0%

pH 〈791〉

Sample solution: Constitute as directed in the labeling.

Acceptance criteria: 6.0–8.5

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

6 ADDITIONAL REQUIREMENTS

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

USP Reference Standards 〈11〉

USP Oxacillin Sodium RS