Bacterial endotoxins 
85
—
Where the label states that Sulbactam Sodium is sterile or must be subjected to further processing during the preparation of injectable dosage forms, it contains not more than 0.17 USP Endotoxin Unit per mg of sulbactam.
Assay—
0.005 M Tetrabutylammonium hydroxide—
Dilute 6.6 mL of a 40% solution of tetrabutylammonium hydroxide with water to obtain 1800 mL of solution. Adjust with 1 M phosphoric acid to a pH of 5.0 ± 0.1, dilute with water to 2000 mL, and mix.
Mobile phase—
Prepare a filtered and degassed mixture of
0.005 M Tetrabutylammonium hydroxide and acetonitrile (1650:350). Make adjustments if necessary (see
System Suitability under
Chromatography 621).
Standard preparation—
Quantitatively dissolve an accurately weighed quantity of
USP Sulbactam RS in
Mobile phase to obtain a solution having a known concentration of about 1 mg per mL.
[NOTE—Inject this solution promptly.
]
Assay preparation—
Transfer about 110 mg of Sulbactam Sodium, accurately weighed, to a 100-mL volumetric flask, dissolve in and dilute with Mobile phase to volume, and mix. [NOTE—Inject this solution promptly.]
Chromatographic system
(see
Chromatography 621)—The liquid chromatograph is equipped with a 230-nm detector and a 4-mm × 30-cm column that contains packing L1. The flow rate is about 2 mL per minute. Chromatograph the
Standard preparation, and record the responses as directed for
Procedure: the column efficiency is not less than 3500 theoretical plates; the tailing factor is not more than 1.5; and the relative standard deviation for replicate injections is not more than 2.0%.
Procedure—
Separately inject equal volumes (about 10 µL) of the
Standard preparation and the
Assay preparation into the chromatograph, record the chromatograms, and measure the areas for the major peaks. Calculate the quantity, in µg, of sulbactam (C
8H
11NO
5S) in each mg of Sulbactam Sodium taken by the formula:
100(CP / W)(rU / rS),
in which
C is the concentration, in mg per mL, of
USP Sulbactam RS in the
Standard preparation; P is the assigned sulbactam content, in µg per mg, of
USP Sulbactam RS;
W is the quantity, in mg, of Sulbactam Sodium taken to prepare the
Assay preparation; and
rU and
rS are the peak areas for sulbactam obtained from the
Assay preparation and the
Standard preparation, respectively.
;)
