Oxacillin 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 Injection is a sterile isoosmotic solution of Oxacillin Sodium in Water for Injection. It contains the equivalent of NLT 90.0% and NMT 115.0% of the labeled amount of oxacillin (C₁₉H₁₉N₃O₅S. It contains dextrose as a tonicity-adjusting agent and one or more suitable buffer substances. It contains no preservatives.

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.

Add the following:

B. The UV spectrum of the major peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay. (USP 1-Dec-2021)

3 ASSAY

Change to read:

Procedure

Solution A: 2.7 g/L of monobasic potassium phosphate

Mobile phase: Acetonitrile, methanol, and Solution A (300:100:700). Adjust with phosphoric acid to a pH of 3.0. (USP 1-Dec-2021)

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

Sample solution: Nominally 0.1 mg/mL of oxacillin from 1 container of Injection that has been allowed to thaw. Use this solution on the day prepared.

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 225 nm.For Identification B, use a diode array detector in the range of 200–400 nm. (USP 1-Dec-2021)

Column: 4-mm × 30-cm; packing L11

Flow rate: 2 mL/min

Injection volume: 10 μL

System suitability

Sample: Standard solution

Suitability requirements (USP 1-Dec-2021)

Tailing factor: NMT 1.6

Relative standard deviation: NMT 2.0%

Analysis

Samples: Standard solution and Sample solution

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

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

r_U = peak response of oxacillin (USP 1-Dec-2021) from the Sample solution

r_S = peak response of oxacillin (USP 1-Dec-2021) 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 the Sample solution (mg/mL)

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

F = conversion factor, 0.001 mg/μg

Acceptance criteria: 90.0%–115.0%

4 SPECIFIC TESTS

Change to read:

Sterility Tests 〈71〉: Meets the requirements (USP 1-Dec-2021)

pH 〈791〉: 6.0–8.5

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

Change to read:

Pyrogen Test 〈151〉: Meets the requirements for a test dose of undiluted Injection equivalent to 20 mg/kg of oxacillin (USP 1-Dec-2021)

5 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve as described in Packaging and Storage Requirements 〈659〉, Injection Packaging. Maintain in the frozen state.

Labeling: It meets the requirements in Labeling 〈7〉, Labels and Labeling for Injectable Products. The label states that it is to be thawed just before use; it describes conditions for proper storage of the resultant solution; it directs that the solution is not to be refrozen.

USP Reference Standards 〈11〉

USP Oxacillin Sodium RS