Cephradine Capsules
»Cephradine Capsules contain not less than 90.0percent and not more than 120.0percent of the labeled amount of cephradine,calculated as the sum of cephradine (C16H19N3O4S)and cephalexin (C16H17N3O4S).
Packaging and storage— Preserve in tight containers.
Labeling— The quantity of cephradine stated in the labeling is in terms of anhydrous cephradine (C16H19N3O4S).
Identification— Mix the contents of 1Capsule with water to obtain a solution having a concentration of about 3mg of cephradine per mL,and filter (test solution).Place a suitable thin-layer chromatographic plate (see Chromatography á621ñ)coated with a 0.25-mm layer of binder-free silica gel in a chamber containing a mixture of n-hexane and tetradecane (95:5)to a depth of about 1cm,allow the solvent front to move the length of the plate,remove the plate from the chamber,and allow the solvent to evaporate.On this plate apply 10µLeach of the test solution and a Standard solution containing 3mg of USP Cephradine RSper mL.Allow the spots to dry,and develop the chromatogram in a solvent system consisting of a mixture of 0.1Mcitric acid,0.1Mdibasic sodium phosphate,and a 1in 15solution of ninhydrin in acetone (60:40:1.5)until the solvent front has moved about three-fourths of the length of the plate.Remove the plate from the developing chamber,mark the solvent front,dry the plate for 10minutes at 110,and examine the chromatogram:the RFvalue of the principal spot obtained from thetest solutioncorresponds to that obtained from the Standard solution.
Dissolution á711ñ—
Medium: 0.12Nhydrochloric acid;900mL.
Apparatus 1: 100rpm.
Time: 45minutes.
Procedure— Determine the amount of C16H19N3O4Sdissolved from UVabsorbances at the wavelength of maximum absorbance at about 255nm of filtered portions of the solution under test,suitably diluted with Dissolution Medium,if necessary,in comparison with a Standard solution having a known concentration of USP Cephradine RSin the same medium.
Tolerances— Not less than 75%(Q)of the labeled amount of C16H19N3O4Sis dissolved in 45minutes.
Uniformity of dosage units á905ñ: meet the requirements.
Loss on drying á731ñ— Dry about 100mg,accurately weighed,of the mixed contents of 4Capsules in a capillary-stoppered bottle in vacuum at a pressure not exceeding 5mm of mercury at 60for 3hours:the Capsule contents lose not more than 7.0%of their weight.
Assay—
Mobile phase,Standard preparation,Resolution solution,and Chromatographic system— Proceed as directed in the Assayunder Cephradine.
Assay preparation— Transfer,as completely as possible,the contents of not less than 20Capsules to a suitable tared container,determine the average weight per Capsule,and mix the combined contents.Transfer an accurately weighed portion of the powder,equivalent to about 125mg of cephradine,to a 250-mLvolumetric flask,add 50mLof Mobile phase,sonicate for about 15minutes,and shake by mechanical means for about 10minutes.Dilute with Mobile phaseto volume,and mix.Filter a portion of this mixture through a filter having a porosity of 0.5µm or finer,discarding the first 5mLof the filtrate.Use the filtrate as the Assay preparation.
Procedure— Separately inject equal volumes (about 10µL)of the Standard cephradine preparationand the Assay preparationinto 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 the portion of Capsules taken by the formula:
0.25CP(rU/rS),
in which Cis the concentration,in mg per mL,of USP Cephradine RSin the Standard preparation,Pis the designated potency,in µg per mg,of USP Cephradine RS,and rUand rSare the sums of the cephradine and cephalexin peak responses obtained from the Assay preparationand the Standard preparation,respectively.
Auxiliary Information— Staff Liaison:William W.Wright,Ph.D.,Scientific Fellow
Expert Committee:(PA7)Pharmaceutical Analysis 7
USP28–NF23Page 421
Phone Number:1-301-816-8335