Identification—
The chromatogram of the
Assay preparationobtained as directed in the
Assayexhibits a major peak for oxacillin,the retention time of which corresponds to that exhibited in the chromatogram of the
Standard preparationobtained as directed in the
Assay.
Assay—
Mobile phase
and Chromatographic system—Proceed as directed in the Assayunder Oxacillin Sodium.
Diluent—
Prepare a mixture of water and acetonitrile (700:300).
Standard preparation—
Prepare a solution of
USP Oxacillin Sodium RSin
Diluenthaving a known concentration of about 0.11mg per mL.
[NOTE—Use this solution on the day prepared.
]
Assay preparation—
Transfer an accurately measured volume of Oxacillin Sodium for Oral Solution,constituted as directed in the labeling,equivalent to about 250mg of oxacillin (C19H19N3O5S),to a 250-mLvolumetric flask,dilute with water to volume,and mix.Transfer 5.0mLof this solution to a 50-mLvolumetric flask,dilute with Diluentto volume,and mix.Filter about 5mLof this solution through a 0.5-µm or finer porosity filter,discarding the first 2mLof the filtrate.Use the clear filtrate as the Assay preparation.[NOTE—Use this Assay preparation on the day prepared.]
Procedure—
Proceed as directed for
Procedurein the
Assayunder
Oxacillin Sodium.Calculate the quantity,in mg,of oxacillin (C
19H
19N
3O
5S)in each mLof the constituted Oxacillin Sodium for Oral Solution taken by the formula:
in which
Vis the volume,in mL,of the constituted Oxacillin Sodium for Oral Solution taken,and the other terms are as defined therein.