Cephapirin Sodium
(sef a pye' rin soe' dee um).
Click to View Image
C17H16N3NaO6S2 445.45

5-Thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, 3-[(acetyl-oxy)methyl]-8-oxo-7-[[(4-pyridinylthio)acetyl]amino]-, monosodium salt, (6R-trans)-.
Monosodium (6R,7R)-3-(hydroxymethyl)-8-oxo-7-[2-(4-pyridylthio)acetamido]-5-thia-1-azabicyclo-[4.2.0]oct-2-ene-2-carboxylate acetate (ester)
[24356-60-3].
» Cephapirin Sodium has a potency equivalent to not less than 855 µg and not more than 1000 µg of cephapirin (C17H17N3O6S2) per mg.
Packaging and storage— Preserve in tight containers.
Labeling— Where it is intended for use in preparing injectable dosage forms, the label states that it is sterile or must be subjected to further processing during the preparation of injectable dosage forms.
USP Reference standards 11
USP Cephapirin Sodium RS Click to View Structure
USP Endotoxin RS
Identification—
B: It responds to the tests for Sodium 191.
Crystallinity 695: meets the requirements.
pH 791: between 6.5 and 8.5, in a solution containing 10 mg of cephapirin per mL.
Water, Method I 921: not more than 2.0%.
Other requirements— Where the label states that Cephapirin Sodium is sterile, it meets the requirements for Sterility and Bacterial endotoxins under Cephapirin for Injection. Where the label states that Cephapirin Sodium must be subjected to further processing during the preparation of injectable dosage forms, it meets the requirements for Bacterial endotoxins under Cephapirin for Injection.
Assay—
Solution A, Solution B, Mobile phase, Extraction solution, Dilution buffer, 10% Acetic acid solution, System suitability solution, Standard preparation, and Chromatographic system— Proceed as directed in the Assay under Cephapirin Benzathine.
Assay preparation— In duplicate, weigh about 50 mg of Cephapirin Sodium, and transfer into a 25-mL volumetric flask. Add about 2.5 mL of Extraction solution and 15.0 mL of Dilution buffer, and mix to dissolve. Add 7.0 mL of acetonitrile, and mix. Allow the flask to return to room temperature, and dilute with water to volume.
Procedure— Separately inject equal volumes (about 2 µL) of the duplicate Standard preparation and the duplicate Assay preparation into the chromatograph, record the chromatograms, and measure the areas for the major peaks. Calculate the quantity, in µg, of cephapirin (C17H17N3O6S2) in each mg of Cephapirin Sodium taken by the formula:
P(WS / WU)(VU / VS)(rU / rS)
in which P is the assigned potency, in µg of cephapirin per mg, of USP Cephapirin Sodium RS; WS and WU are the quantities of USP Cephapirin Sodium RS and Cephapirin Sodium, in mg, used to prepare the Standard preparation and the Assay preparation, respectively; VU and VS are the final volumes, in mL, of the Assay preparation and the Standard preparation, respectively; and rU and rS are the average peak areas of the cephapirin peaks obtained from the Assay preparation and the Standard preparation, respectively.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Morgan Puderbaugh, B.S.
Associate Scientific Liaison
1-301-998-6833
(SM32010) Monographs - Small Molecules 3
Reference Standards RS Technical Services
1-301-816-8129
rstech@usp.org
USP35–NF30 Page 2592
Pharmacopeial Forum: Volume No. 30(2) Page 471