Narasin Premix
»Narasin Premix contains Narasin Granular mixed with suitable diluents and inactive ingredients.It contains not less than 90percent and not more than 110percent of the labeled amount of narasin.
Packaging and storage— Preserve in well-closed containers.Avoid moisture and excessive heat.
Labeling— Label it to indicate that it is for animal use only.The label bears the statement,“Do not feed undiluted.”
Identification— The retention time of the major peak for narasin Ain the chromatogram of the Assay preparationcorresponds to that of the Standard preparation,as obtained in the Assay.
Loss on drying á731ñ— Dry it in vacuum at 60for 3hours:it loses not more than 12%of its weight.
Assay—
Mobile phase ,Neutralized methanol,Diluent,Derivatizing reagent,Standard preparations,Resolution solution,and Chromatographic system—Proceed as directed in the Assayunder Narasin Granular.
Assay preparation— Transfer about 5g of Narasin Premix,accurately weighed,to a suitable container,add 200.0mLof Diluent,and shake by mechanical means for 1hour.Allow the solids to settle,and dilute an accurately measured volume of the supernatant quantitatively with Diluentto obtain a solution containing about 20µg of narasin per mL.Pass a portion of this solution through a filter having a porosity of 0.5µm or less,and use the filtrate as the Assay preparation.
Procedure— Proceed as directed for Procedurein the Assayunder Narasin Granular.Calculate the biopotency,in mg per g,of the Narasin Premix taken to prepare the Assay preparationby the formula:
(CA+CD+IF)(VE/M),
in which Mis the weight,in g,of Premix taken to prepare the Assay preparation,and the other terms are as defined therein.
Auxiliary Information— Staff Liaison:Ian DeVeau,Ph.D.,Senior Scientist
Expert Committee:(VET)Veterinary Drugs
USP28–NF23Page 1339
Phone Number:1-301-816-8178