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.
Assay—
Mobile phase
and Chromatographic system—Proceed as directed in the Assay under Oxacillin Sodium.
Diluent—
Prepare a mixture of water and acetonitrile (700:300).
Standard preparation—
Prepare a solution of
USP Oxacillin Sodium RS in
Diluent having a known concentration of about 0.11 mg 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 250 mg of oxacillin (C19H19N3O5S), to a 250-mL volumetric flask, dilute with water to volume, and mix. Transfer 5.0 mL of this solution to a 50-mL volumetric flask, dilute with Diluent to volume, and mix. Filter about 5 mL of this solution through a 0.5-µm or finer porosity filter, discarding the first 2 mL of the filtrate. Use the clear filtrate as the Assay preparation. [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 constituted Oxacillin Sodium for Oral Solution taken by the formula:
in which
V is the volume, in mL, of the constituted Oxacillin Sodium for Oral Solution taken, and the other terms are as defined therein.
905
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