Labeling—
It meets the requirements for
Labeling under
Injections 
1
. The label states that it is to be thawed just prior to use, describes conditions for proper storage of the resultant solution, and directs that the solution is not to be refrozen.
Identification—
The chromatogram of the
Assay preparation obtained as directed in the
Assay exhibits a major peak for oxacillin, the retention time of which corresponds to that exhibited in the chromatogram of the
Standard preparation obtained as directed in the
Assay.
Pyrogen—
It meets the requirements of the
Pyrogen Test 151, the test dose being a volume of undiluted Injection providing the equivalent of 20 mg of oxacillin per kg.
Assay—
Mobile phase
, Standard preparation, and Chromatographic system—Proceed as directed in the Assay under Oxacillin Sodium.
Assay preparation—
Allow one container of Injection to thaw, and mix. Transfer an accurately measured volume of Injection, equivalent to about 50 mg of oxacillin, to a 100-mL volumetric flask, dilute with water to volume, and mix. Transfer 10.0 mL of this solution to a 50-mL volumetric flask, dilute with water to volume, and mix. [NOTE—Use this Assay preparation on the day prepared.]
Procedure—
Proceed as directed for
Procedure in the
Assay under
Oxacillin Sodium. Calculate the quantity, in mg, of oxacillin (C
19H
19N
3O
5S) in each mL of the Injection taken by the formula:
0.5(CE / V)(rU / rS),
in which
C is the concentration, in mg per mL, of
USP Oxacillin Sodium RS in the
Standard preparation, E is the oxacillin equivalent, in µg per mg, of
USP Oxacillin Sodium RS,
V is the volume, in mL, of Injection taken to prepare the
Assay preparation, and
rU and
rS are the oxacillin peak responses obtained from the
Assay preparation and the
Standard preparation, respectively.
