Cephradine for Oral Suspension
» Cephradine for Oral Suspension is a dry mixture of Cephradine and one or more suitable buffers, colors, diluents, and flavors. It contains not less than 90.0 percent and not more than 125.0 percent of the labeled amount of cephradine, calculated as the sum of cephradine (C16H19N3O4S) and cephalexin (C16H17N3O4S).
Packaging and storage— Preserve in tight containers.
Identification— Constitute 1 container of Cephradine for Oral Suspension as directed in the labeling. Mix a portion of the resulting suspension with water to obtain a concentration of about 3 mg of cephradine per mL, and filter (test solution). Proceed as directed in the Identification test under Cephradine Capsules, beginning with “Place a suitable thin-layer chromatographic plate”: the RF value of the principal spot obtained from the test solution corresponds to that obtained from the Standard solution.
Uniformity of dosage units 905
For solid packaged in single-unit containers: meets the requirements.
Deliverable volume 698: meets the requirements.
pH 791: between 3.5 and 6.0, in the suspension constituted as directed in the labeling.
Water, Method I 921: not more than 1.5%.
Mobile phase, Standard preparation, Resolution solution, and Chromatographic system— Proceed as directed in the Assay under Cephradine.
Assay preparation— Constitute Cephradine for Oral Suspension as directed in the labeling. Dilute an accurately measured volume of the suspension so obtained, freshly mixed and free from air bubbles, quantitatively with Mobile phase to obtain a solution containing about 0.5 mg of cephradine per mL. Filter a portion of this mixture through a filter having a porosity of 0.5 µm or finer, discarding the first 5 mL of the filtrate. Use the filtrate as the Assay preparation.
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. Calculate the quantity, in mg, of cephradine (sum of cephradine and cephalexin) in each mL of constituted Oral Suspension taken by the formula:
(CP)(L / 1000D)(rU / rS)
in which C is the concentration, in mg per mL, of USP Cephradine RS in the Standard preparation; P is the designated potency, in µg per mg, of USP Cephradine RS; L is the labeled quantity, in mg of cephradine, in each mL of the constituted Oral Suspension; D is the concentration, in mg of cephradine per mL, of the Assay preparation, based on the labeled quantity of cephradine per mL of constituted Oral Suspension and the extent of dilution; and rU and rS are the sums of the cephradine and cephalexin peak responses 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 Ahalya Wise, M.S.
(MDANT05) Monograph Development-Antibiotics
Reference Standards Lili Wang, Technical Services Scientist
USP32–NF27 Page 1880