Tetracycline Hydrochloride Soluble Powder »Tetracycline Hydrochloride Soluble Powder contains not less than 90.0percent and not more than 125.0percent of the labeled amount of C22H24N2O8·HCl. Packaging and storage— Preserve in tight containers. Labeling— Label it to indicate that it is intended for veterinary use only. USP Reference standards á11ñ USP Tetracycline Hydrochloride RS. Identification— Shake a suitable quantity of Powder with methanol to obtain a solution containing the equivalent of 1mg of tetracycline hydrochloride per mL,and filter.Using the filtrate so obtained as the Test Solution,proceed as directed under Identification—Tetracyclines á193ñ. Loss on drying á731ñ Dry about 100mg,accurately weighed,in a capillary-stoppered bottle in vacuum at a pressure not exceeding 5mm of mercury at 60for 3hours:it loses not more than 2.0%of its weight. Assay— Transfer an accurately weighed quantity of Powder to a high-speed blender jar containing an accurately measured volume of 0.1Nhydrochloric acid,so that the solution so obtained contains not less than 150µg of tetracycline hydrochloride per mL,and blend for about 3to 5minutes.Proceed as directed for tetracycline under Antibiotics—Microbial Assays á81ñ,diluting an accurately measured volume of this solution quantitatively and stepwise with water to yield a Test Dilutionhaving a concentration 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 1888 Phone Number:1-301-816-8178