Procedure
Proceed as directed for 
Procedure in the 
Assay under 
Aztreonam for Injection. Calculate the quantity, in mg, of aztreonam (C
13H
17N
5O
8S
2) in the volume of Injection taken by the formula: 
(CS PS L / 1000D)(rU / rS),
in which 
CS is the concentration, in mg per mL, of 
USP Aztreonam RS in the 
Standard preparation; PS is the assigned purity, in µg per mg, of 
USP Aztreonam RS;
 L is the labeled quantity, in mg, of aztreonam (C
13H
17N
5O
8S
2) in the volume of Injection taken; 
D is the concentration, in mg of aztreonam per mL, based on the labeled quantity in the volume of Injection taken; and 
rU and 
rS are the aztreonam peak responses obtained from the 
Assay preparation and the 
Standard preparation, respectively.