Assay preparation 1 (where it is packaged for dispensing)—Constitute Neomycin for Injection as directed in the labeling.Withdraw all of the withdrawable contents,using a suitable hypodermic needle and syringe,and dilute quantitatively with Buffer No.3to obtain a solution having a convenient concentration.

Assay preparation 2 (where it is packaged for dispensing and where the labeling states the quantity of neomycin in a given volume of constituted solution)—Constitute Neomycin for Injection as directed in the labeling.Dilute an accurately measured volume of the constituted solution quantitatively with Buffer No.3to obtain a solution having a convenient concentration.

Procedure— Proceed as directed for neomycin under Antibiotics—Microbial Assays á81ñ,using an accurately measured volume of Assay preparationdiluted quantitatively and stepwise with Buffer No.3to yield a Test Dilution having a concentration assumed to be equal to the median dose level of the Standard.