Assay
Acetic acid solution
,
0.05M Sodium acetate,Diluent,Mobile phase,Standard preparation,Resolution solution,and
Chromatographic systemProceed as directed in the
Assayunder
Nafcillin Sodium.
Assay preparation 1
(where it is represented as being in a single-dose container)Constitute Nafcillin for Injection in a volume of water,accurately measured,corresponding to the volume of solvent specified in the labeling.Withdraw all of the withdrawable contents,using a suitable hypodermic needle and syringe,and dilute quantitatively with Diluentto obtain a solution having a concentration of about 0.4mg of nafcillin (C21H22N2O5S)per mL.
Assay preparation 2
(where the label states the quantity of nafcillin in a given volume of constituted solution)Constitute Nafcillin for Injection in a volume of water,accurately measured,corresponding to the volume of solvent specified in the labeling.Dilute an accurately measured volume of the constituted solution quantitatively with Diluentto obtain a solution having a concentration of about 0.4mg of nafcillin (C21H22N2O5S)per mL.
Procedure
Proceed as directed for
Procedurein the
Assayunder
Nafcillin Sodium.Calculate the quantity,in mg,of nafcillin (C
21H
22N
2O
5S)in the portion of constituted Nafcillin for Injection taken by the formula:
(C/1000)(L/D)(rU/rS),
in which
Lis the labeled quantity,in mg,of nafcillin in the portion of Nafcillin for Injection taken;
Dis the concentration,in mg per mL,of nafcillin in
Assay preparation 1or
Assay preparation 2,as appropriate,based on the volume of constituted Nafcillin for Injection taken and the extent of dilution;and the other terms are as defined therein.
Perform the above procedure on 10containers where it is represented as being in a single-dose container and,if necessary,on 10containers where the label states the quantity of nafcillin in a given volume of constituted solution.Use the individual results to determine the
Uniformity of dosage unitsand the average thereof as the
Assayvalue.