Packaging and storage— Preserve in well-closed disposable syringes.

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

USP Reference standards 11— USP Penicillin G Potassium RS. USP Penicillin G Procaine RS.

Identification— Transfer a portion of it, equivalent to about 100,000 Penicillin G Units, to a test tube, add 25 mL of methanol, and shake. Allow to separate, and use the methanol layer as the test solution. Prepare a Standard solution of USP Penicillin G Procaine RS in methanol containing about 4.5 mg per mL. Apply separately 10 µL of each solution to a thin-layer chromatographic plate (see Chromatography 621) coated with a 0.25-mm layer of chromatographic silica gel mixture. Allow the spots to dry, and develop the chromatogram in a solvent system consisting of a mixture of butanol, isopropyl alcohol, acetone, and water (4:4:2:2) 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 allow the solvent to evaporate. Expose the plate to iodine vapors in a closed chamber for about 15 minutes, and locate the spots: the RF values and colors of the two principal spots obtained from the test solution correspond to those obtained from the Standard solution.

Water, Method I 921: not more than 1.4%, 20 mL of a mixture of toluene and methanol (7:3) being used in place of methanol in the titration vessel.

Residual solvents 467: meets the requirements.

Assay— Proceed as directed under Antibiotics—Microbial Assays 81, expelling the contents of 1 syringe of Intramammary Infusion into a high-speed glass blender jar containing 499.0 mL of Buffer No. 1 and 1.0 mL of polysorbate 80, and blending for 3 to 5 minutes. Allow to stand for about 10 minutes, and dilute an accurately measured volume of the aqueous phase quantitatively and stepwise with Buffer No. 1 to obtain a Test Dilution having a concentration assumed to be equal to the median dose level of the Standard.

Expert Committee : (VET05) Veterinary Drugs 05

USP29–NF24 Page 1661

Phone Number : 1-301-816-8178