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921
:
not more than 1.0%, 20 mL of a mixture of toluene and methanol (7:3) being used in place of methanol in the titration vessel.
467:
meets the requirements.
81, except to use Staphylococcus aureus ATCC No. 12692 as the test organism. Prepare the inoculum by growing the organism at 32
to 35 for 24 hours on Medium 1 to which has been added a solution of novobiocin sodium, containing the equivalent of 2.5 mg of novobiocin per mL that has been filtered through a membrane filter having a 0.2-µm porosity, so that the medium contains the equivalent of 10 µg of novobiocin per mL. Use an inoculum composition of about 5 mL of stock suspension in each 100 mL of Medium 1. Expel the contents of a syringe of Intramammary Infusion into a high-speed glass blender jar containing 1.0 mL of polysorbate 80 and 499.0 mL of Buffer No. 1, and blend for 3 to 5 minutes. Allow to stand for 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 of penicillin G assumed to be equal to the median dose level of the Standard.
81, expelling the contents of a syringe of Intramammary Infusion into a high-speed blender jar containing 1.0 mL of polysorbate 80 and 499.0 mL of Buffer No. 3, and blend for 3 to 5 minutes. Allow to stand for 10 minutes. To an accurately measured volume of the aqueous phase add sufficient penicillinase to inactivate the penicillin G therein, and dilute quantitatively and stepwise with Buffer No. 6 to obtain a Test Dilution having a concentration of novobiocin assumed to be equal to the median dose level of the Standard. [NOTE—Store this Test Dilution at 37 for 30 minutes and allow to cool before using it to fill the cylinders on the plates.]