Assay
pH 3.4 acetate buffer
Transfer 50 mL of 0.1 M sodium acetate to a 1000-mL volumetric flask, dilute with 0.1 N acetic acid to volume, and mix.
Mobile phase
Prepare a suitable mixture of pH 3.4 acetate buffer and acetonitrile (about 10:1). Filter through a membrane filter (1 µm or finer porosity), and degas.
Internal standard solution
Prepare a solution of orcinol in water containing 1.5 mg per mL.
Standard preparation
Dissolve a suitable quantity of
USP Cefuroxime Sodium RS, accurately weighed, in water to obtain a solution having a known concentration of about 1 mg of cefuroxime (C
16H
16N
4O
8S) per mL. Immediately transfer 5.0 mL of the resulting solution to a 100-mL volumetric flask, add 20.0 mL of
Internal standard solution, dilute with water to volume, and mix. This
Standard preparation contains about 0.05 mg of cefuroxime per mL.
Assay preparation
Using a suitable quantity of Cefuroxime Sodium, accurately weighed, proceed as directed in the first sentence under Standard preparation. Immediately transfer 5.0 mL of the resulting solution to a 100-mL volumetric flask, add 20.0 mL of Internal standard solution, dilute with water to volume, and mix.
Chromatographic system
(see
Chromatography 621)The liquid chromatograph is equipped with a 254-nm detector and a 4.6-mm × 15-cm column that contains 5-µm packing L15. The flow rate is about 2 mL per minute. Chromatograph the
Standard preparation, and record the peak responses as directed under
Procedure: the column efficiency determined from the analyte peak is not less than 1300 theoretical plates; the tailing factor for the analyte peak is not more than 2.0; the resolution,
R, between the analyte and internal standard peaks is not less than 3.5; 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 responses for the major peaks. The relative retention times are about 0.5 for cefuroxime and 1.0 for orcinol. Calculate the quantity, in µg, of cefuroxime per mg of the Cefuroxime Sodium taken by the formula:
1000(C/M)(RU / RS),
in which
C is the concentration, in mg of cefuroxime (C
16H
16N
4O
8S) per mL, in the
Standard preparation; M is the concentration, in mg per mL, in the
Assay preparation based on the weight of Cefuroxime Sodium taken and the extent of dilution; and
RU and
RS are the peak response ratios of the cefuroxime peak to the internal standard peak obtained from the
Assay preparation and the
Standard preparation, respectively.