Packaging and storage— Preserve in well-closed containers.

Labeling— Label it to indicate that it is for veterinary use only.

USP Reference standards 11— USP Bacitracin Zinc RS.

pH 791: between 8.0 and 9.5, in a solution containing 25 mg of specimen per mL.

Loss on drying 731— Dry about 100 mg, accurately weighed, in a capillary-stoppered bottle in vacuum at a pressure not exceeding 5 mm of mercury at 60 for 3 hours: it loses not more than 8.5% of its weight.

Residual solvents 467: meets the requirements.

Assay— Transfer an accurately weighed quantity of Soluble Bacitracin Methylene Disalicylate to a high-speed glass blender jar. Add 99.0 mL of sodium bicarbonate solution (1 in 50) and 1.0 mL of polysorbate 80, and blend for about 3 minutes. Proceed as directed for bacitracin under Antibiotics—Microbial Assays 81, adding a sufficient volume of 0.01 N hydrochloric acid to an accurately measured volume of this solution so that the amount of hydrochloric acid in the Test Dilution will be the same as in the median dose level of the Standard, and quantitatively diluting with Buffer No. 1 to obtain a Test Dilution having a concentration of bacitracin assumed to be equal to the median dose level of the Standard.

Expert Committee : (VET05) Veterinary Drugs 05

USP29–NF24 Page 235

Phone Number : 1-301-816-8178