Tetracycline Hydrochloride and Novobiocin Sodium Tablets »Tetracycline Hydrochloride and Novobiocin Sodium Tablets contain the equivalent of not less than 90.0percent and not more than 125.0percent of the labeled amounts of tetracycline hydrochloride (C22H24N2O8·HCl)and novobiocin (C31H36N2O11). Packaging and storage— Preserve in tight containers. Labeling— Label the Tablets to indicate that they are intended for veterinary use only. USP Reference standards á11ñ USP Tetracycline Hydrochloride RS.USP Novobiocin RS. Identification— Shake a suitable quantity of finely powdered Tablets with methanol to obtain a solution containing 1mg of tetracycline hydrochloride per mL,and filter.Using the filtrate as the Test Solution,proceed as directed under Identification—Tetracyclines á193ñ. Disintegration á701ñ: 60minutes,simulated gastric fluid TSbeing substituted for water in the test. Uniformity of dosage units á905ñ: meet the requirements for Weight Variationwith respect to tetracycline hydrochloride and to novobiocin sodium. Loss on drying á731ñ Dry about 100mg,accurately weighed,of finely powdered Tablets in a capillary-stoppered bottle in vacuum at a pressure not exceeding 5mm of mercury at 60for 3hours:it loses not more than 6.0%of its weight. Limit of 4-epianhydrotetracycline á226ñ To an accurately weighed quantity of finely powdered Tablets,equivalent to about 250mg of tetracycline hydrochloride,add 10mLof 0.1Nhydrochloric acid,and adjust with 6Nammonium hydroxide to a pHof 7.8.Transfer this solution with the aid of EDTA Bufferto a 50-mLvolumetric flask,dilute with EDTA Bufferto volume,and mix.Use this solution,without delay,as the Test Solution:not more than 2.0%is found. Assay for tetracycline hydrochloride— Proceed as directed for tetracycline under Antibiotics—Microbial Assays á81ñ,except to use Escherichia coliATCC10536as the test organism instead of Staphylococcus aureusATCC29737and an inoculum composition of about 0.2mLof stock suspension in each 100mLof Medium 3.Transfer not less than 5Tablets to a high-speed blender jar containing an accurately measured volume of 0.1Nhydrochloric acid,so that,after blending for about 3to 5minutes,the solution so obtained contains not less than 150µg of tetracycline hydrochloride per mL.Dilute an accurately measured volume of this solution quantitatively and stepwise with water to obtain a Test Dilutionhaving a concentration of tetracycline hydrochloride assumed to be equal to the median dose level of the Standard. Assay for novobiocin— Proceed as directed for novobiocin under Antibiotics—Microbial Assays á81ñ,blending not less than 5Tablets for 3to 5minutes in a high-speed glass blender jar containing 1.0mLof polysorbate 80and a sufficient accurately measured volume of Buffer No.3to provide a stock solution of convenient concentration.Dilute an accurately measured volume of this stock solution quantitatively and stepwise with Buffer No.6to obtain a Test Dilutionhaving a concentration of novobiocin assumed to be equal to the median dose level of the Standard. Auxiliary Information— Staff Liaison:Ian DeVeau,Ph.D.,Senior Scientist Expert Committee:(VET)Veterinary Drugs USP28–NF23Page 1891 Phone Number:1-301-816-8178