Pyrogen 
151
—
Where the label states that it is sterile or must be subjected to further processing during the preparation of injectable dosage forms, it meets the requirements, the test dose being 1.0 mL per kg of a solution in pyrogen-free sodium carbonate solution (prepared by dissolving 14.0 g of sodium carbonate, previously heated at 170
for not less than 4 hours, in 1000 mL of sterile water for injection) containing 60 mg per mL.
Water, Method I 921:
not more than 1.5%, the
Test Preparation being prepared as directed for a hygroscopic specimen, except to use 20 mL of a mixture of formamide (previously dried over anhydrous sodium sulfate for 24 hours) and methanol (2:1), instead of methanol, to dissolve the specimen, to use two 5-mL portions of the same formamide and methanol mixture to rinse the container, and to determine the water content of the formamide and methanol mixture.
Assay—
pH 6.8 buffer—
Dissolve 6.4 g of monobasic potassium phosphate and 18.9 g of dibasic sodium phosphate in 750 mL of water, adjust with 1 N sodium hydroxide to a pH of 6.8 ± 0.1, dilute with water to 1000 mL, and mix.
Mobile phase—
Prepare a suitable mixture of water, acetonitrile, and glacial acetic acid (50:10:1). Filter through a suitable filter of 0.5 µm or finer porosity, and degas. Make adjustments if necessary (see
System Suitability under
Chromatography 621).
Internal standard solution—
Prepare a solution of phthalimide in methanol containing 1.5 mg per mL.
Standard preparation—
Transfer about 50 mg of
USP Cefmenoxime Hydrochloride RS, accurately weighed, to a 50-mL volumetric flask, add 10 mL of
pH 6.8 buffer, and dissolve by swirling. Dilute with
Mobile phase to volume, and mix. Transfer 4.0 mL of this solution to a second 50-mL volumetric flask, add 20.0 mL of
Internal standard solution, dilute with
Mobile phase to volume, and mix. This solution contains the equivalent of about 80 µg of cefmenoxime (C
16H
17N
9O
5S
3) per mL.
Assay preparation—
Transfer about 50 mg of Cefmenoxime Hydrochloride, accurately weighed, to a 50-mL volumetric flask, add 10 mL of pH 6.8 buffer, and dissolve by swirling. Dilute with Mobile phase to volume, and mix. Transfer 4.0 mL of this solution to a second 50-mL volumetric flask, add 20.0 mL of Internal standard solution, dilute with Mobile phase to volume, and mix.
Chromatographic system
(see
Chromatography 621)—The liquid chromatograph is equipped with a 254-nm detector and a 4-mm × 15-cm column that contains packing L1. The flow rate is about 1 mL per minute. Chromatograph the
Standard preparation, and record the peak responses as directed for
Procedure: the resolution,
R, between the phthalimide and the cefmenoxime peaks is not less than 2.3; the column efficiency, determined from the cefmenoxime peak, is not less than 1200 theoretical plates when calculated by the formula:
5.545(tr / Wh / 2)2,
the tailing factor for the cefmenoxime peak is not more than 1.6; and the relative standard deviation of replicate injections is not more than 2.0%.
Procedure—
[NOTE—Use peak areas where peak responses are indicated.
] Separately inject equal volumes (about 10 µL) of the
Standard preparation and the
Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity, in µg, of cefmenoxime (C
16H
17N
9O
5S
3) in each mg of the Cefmenoxime Hydrochloride taken by the formula:
(WS PS / WU)(RU / RS),
in which
WS is the weight, in mg, of
USP Cefmenoxime Hydrochloride RS taken to prepare the
Standard preparation;
PS is the designated cefmenoxime (C
16H
17N
9O
5S
3) content, in µg per mg, of
USP Cefmenoxime Hydrochloride RS;
WU is the weight, in mg, of Cefmenoxime Hydrochloride taken to prepare the
Assay preparation, and
RU and
RS are the peak response ratios of the cefmenoxime peak to the internal standard peak obtained from the
Assay preparation and the
Standard preparation, respectively.
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(Z)]]-.