Penicillin G Procaine and Dihydrostreptomycin Sulfate Intramammary Infusion
»Penicillin G Procaine and Dihydrostreptomycin Sulfate Intramammary Infusion is a suspension of Penicillin G Procaine and Dihydrostreptomycin Sulfate in a suitable vegetable oil vehicle.It may contain suitable gelling and thickening agents.It contains not less than 90.0percent and not more than 120.0percent of the labeled amounts of Penicillin G Units and of dihydrostreptomycin (C21H41N7O12).
Packaging and storage— Preserve in well-closed,disposable syringes.
Labeling— Label it to indicate that it is intended for veterinary use only.
Identification—
B: Place a portion of it,equivalent to about 100mg of dihydrostreptomycin,in a separator,add 20mLof chloroform and 20mLof water,and shake by mechanical means for 15minutes.Allow to separate,and discard the lower chloroform layer.Repeat the extraction with a 20-mLportion of chloroform,discarding the chloroform layer.Use the aqueous layer as the test solution.Prepare a Standard solution of USP Dihydrostreptomycin Sulfate RSin water containing 6.5mg per mL.Apply separately 30µLof each solution to a thin-layer chromatographic plate (see Chromatography á621ñ)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 n-propyl alcohol,water,pyridine,and glacial acetic acid (15:12:10:2)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.Spray the plate with a reagent prepared by dissolving 2g of ninhydrin in 100mLof alcohol and adding 20mLof glacial acetic acid,heat the plate at 110for 10minutes,and examine the chromatograms:the RFvalue and color of the principal spot obtained from the test solution correspond to those obtained from the Standard solution.
Water,Method Iá921ñ: not more than 1.4%,20mLof a mixture of toluene and methanol (7:3)being used in the titration vessel in place of methanol.
Assay for penicillin G— Proceed as directed for penicillin Gunder Antibiotics—Microbial Assays á81ñ,expelling the contents of 1syringe of Intramammary Infusion into a high-speed glass blender jar containing 499.0mLof Buffer No.1and 1.0mLof polysorbate 80,and blending for 3to 5minutes.Allow to stand for about 10minutes,and dilute an accurately measured volume of the aqueous phase quantitatively and stepwise with Buffer No.1to obtain a Test Dilutionhaving a concentration of penicillin Gassumed to be equal to the median dose level of the Standard.
Assay for dihydrostreptomycin— Proceed as directed for the cylinder-plate assay for dihydrostreptomycin under Antibiotics—Microbial Assays á81ñ,expelling the contents of 1syringe of Intramammary Infusion into a high-speed glass blender jar containing 499.0mLof Buffer No.3and 1.0mLof polysorbate 80,and blending for 3to 5minutes.Allow to stand for about 10minutes,and to an accurately measured volume of the aqueous phase add an accurately measured volume of penicillinase sufficient to inactivate the penicillin Gcontained therein.Dilute this solution quantitatively with Buffer No.3to obtain a Test Dilutionhaving a concentration of dihydrostreptomycin assumed to be equal to the median dose level of the Standard,and store at 37for 30minutes before filling the cylinders.
Auxiliary Information— Staff Liaison:Ian DeVeau,Ph.D.,Senior Scientist
Expert Committee:(VET)Veterinary Drugs
USP28–NF23Page 1492
Phone Number:1-301-816-8178
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