Packaging and storage— Preserve in tight containers.

Labeling— Label Boluses to indicate that they are for veterinary use only.

USP Reference standards á11ñ— USP Neomycin Sulfate RS.

Identification— Blend a Bolus with 250mLof water.Filter a portion of the suspension obtained.If necessary,dilute a portion of the filtrate with water to obtain a test solution containing about 2mg of neomycin per mL.Dissolve a quantity of USP Neomycin Sulfate RSin water to obtain a Standard solution containing about 2mg of neomycin per mL.Separately apply 1µLof each solution to a thin-layer chromatographic plate (see Chromatography á621ñ)coated with a 0.25-mm layer of chromatographic silica gel mixture.Develop the chromatogram in a solvent system consisting of a mixture of water,butyl alcohol,glacial acetic acid,and pyridine (35:30:22:6)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,and dry at about 110for about 5minutes.Spray the plate evenly with a solution of ninhydrin (2mg per mL),and dry the plate at about 100for about 5minutes.Locate the spots on the plate:the RFvalue of the principal spot in the chromatogram obtained from the test solution corresponds to that of the principal spot in the chromatogram obtained from the Standard solution.

Uniformity of dosage units á905ñ: meet the requirements for Weight Variation.

Disintegration á701ñ: 60minutes.

Assay— Proceed as directed for the assay of neomycin under Antibiotics—Microbial Assays á81ñ,the Test Dilutionbeing prepared as follows.Blend an accurately counted number of Boluses (not less than 2)at high speed in a blender jar with a sufficient accurately measured volume of Buffer No.3to obtain a stock solution having a convenient concentration.Dilute this stock solution quantitatively and stepwise with Buffer No.3to obtain a Test Dilutionhaving a concentration assumed to be equal to the median dose level of the Standard.

Expert Committee:(VET)Veterinary Drugs

USP28–NF23Page 1342

Phone Number:1-301-816-8178