Cephapirin Benzathine Intramammary Infusion
»Cephapirin Benzathine Intramammary Infusion is a suspension of Cephapirin Benzathine in a suitable vegetable oil vehicle.It contains the equivalent of not less than 90.0percent and not more than 120.0percent of the labeled quantity of cephapirin (C17H17N3O6S2).It contains a suitable dispersing agent.
Packaging and storage— Preserve in well-closed unit-dose disposable syringes at controlled room temperature.
Labeling— Label Intramammary Infusion to indicate that it is for veterinary use only.
Identification,Infrared Absorption á197Kñ— Prepare the test specimen as follows.Transfer the contents of 1syringe of Intramammary Infusion to a 50-mLcentrifuge tube,add 25mLof toluene,mix for about 1minute,and centrifuge.Remove and discard the toluene layer without disturbing the residue in the centrifuge tube.Wash the residue with two 25-mLportions of toluene.Dry the residue in vacuum at 60,and use the dried residue as the test specimen.Mix the dried residue with 9parts of potassium bromide,and record the IRspectrum,using the diffuse reflectance technique:the IRabsorption spectrum so obtained corresponds to that of a similar dispersion of USP Cephapirin Benzathine RSin potassium bromide.
Water,Method Iá921ñ: not more than 1.0%,10mLof Intramammary Infusion being tested.
Change to read:
Assay—
Solution A,Solution B,Mobile phase,Extraction solution,Dilution buffer,10%Acetic acid solution,System suitability solution,Standard preparation,andChromatographic system— Proceed as directed in the Assay under Cephapirin Benzathine.
Assay preparation— Express the entire contents of a syringe of the Intramammary Infusion into a centrifuge tube.For each mLof Intramammary Infusion,add 1.0n-heptane and 1.5mLof Extraction solution,cap,and vortex at high speed for 5minutes.Centrifuge for 5minutes at a sufficient speed to break the emulsion.Remove the aqueous layer,and pass through a 0.45-µm nylon filter,discarding the first 0.5mL.Transfer 2.5mLof the filtered aqueous phase into a 25-mLvolumetric flask that contains a solution composed of 15.0mLof Dilution bufferand 7.0mLof acetonitrile.Add water to volume,and mix well to obtain a single phase.
Procedure— Separately inject equal volumes (about 2µL)of the duplicate Standard preparationand the Assay preparationinto the chromatograph,record the chromatograms,and measure the areas of the major peaks.Calculate the quantity,in mg,of cephapirin (C17H17N3O6S2)in each syringe of Intramammary Infusion taken by the formula:
15PW(VU/VS)(rU/rS),
in which Pis the assigned potency,in µg cephapirin per mg,of USP Cephapirin Sodium RS;Wis the quantity of USP Cephapirin Sodium RS,in mg,used to prepare the Standard preparation;VSis the final volume,in mL,of the Standard preparation;VUis the entire volume of Intramammary Infusion,in mL,in one syringe;and rUand rSare the peak area and the average peak area of the cephapirin peaks obtained from the Assay preparation and the Standard preparation,respectively.USP28
Auxiliary Information— Staff Liaison:Ian DeVeau,Ph.D.,Senior Scientist
Expert Committee:(VET)Veterinary Drugs
USP28–NF23Page 419
Pharmacopeial Forum:Volume No.30(2)Page 470
Phone Number:1-301-816-8178