Identification—
Solution:
20 µg per mL.
Medium:
0.1 M sodium bicarbonate.
B:
The retention time of the major peak for cefazolin in the chromatogram of the
Assay preparation corresponds to that in the chromatogram of the
Standard preparation, as obtained in the
Assay.
C:
It responds to the tests for
Sodium 
191
.
Assay—
pH 3.6 Buffer, pH 7.0 Buffer, Mobile phase, Internal standard solution, Standard preparation, and Chromatographic system—
Prepare as directed in the
Assay under
Cefazolin.
Assay preparation—
Transfer about 50 mg of Cefazolin Sodium, accurately weighed, to a 50-mL volumetric flask, dissolve in and dilute with pH 7.0 Buffer to volume, and mix. Transfer 5.0 mL of this solution to a 100-mL volumetric flask, add 5.0 mL of Internal standard solution, dilute with pH 7.0 Buffer to volume, and mix.
Procedure—
Proceed as directed for
Procedure in the
Assay under
Cefazolin. Calculate the quantity, in mg, of cefazolin sodium (C
14H
13NaN
8O
4S
3) in the portion of Cefazolin Sodium taken to prepare the
Assay preparation by the formula:
(476.49 / 454.51)(1000C)(RU / RS),
in which 476.49 and 454.51 are the molecular weights of cefazolin sodium and cefazolin, respectively;
C is the concentration, in mg per mL, of
USP Cefazolin RS in the
Standard preparation, calculated on the anhydrous basis; and the other terms are as defined therein.
10
and