Zinc Sulfate Injection »Zinc Sulfate Injection is a sterile solution of Zinc Sulfate in Water for Injection.It contains not less than 90.0percent and not more than 110.0percent of the labeled amount of zinc (Zn). Packaging and storage— Preserve in single-dose or multiple-dose containers. Labeling— Label the Injection in terms of its content of anhydrous zinc sulfate (ZnSO4)and in terms of its content of elemental zinc.Label it to state that it is not intended for direct injection but is to be added to other intravenous solutions. USP Reference standards á11ñ USP Endotoxin RS. Identification— It responds to the tests for Zinc á191ñand for Sulfate á191ñ. Bacterial endotoxins á85ñ It contains not more than 25.0USP Endotoxin Units per mg of zinc. pHá791ñ: between 2.0and 4.0. Particulate matter á788ñ: meets the requirements for small-volume injections. Other requirements— It meets the requirements under Injections á1ñ. Assay— [NOTE—The Standard preparations and the Assay preparation may be diluted quantitatively with water,if necessary,to yield solutions of suitable concentrations adaptable to the linear or working range of the instrument.] Standard preparations and Assay preparation—Proceed as directed in the Assayunder Zinc Chloride Injection. Procedure— Concomitantly determine the absorbances of the Standard preparationsand the Assay preparationat the zinc emission line of 213.8nm with a suitable atomic absorption spectrophotometer (see Spectrophotometry and Light-scattering á851ñ)equipped with a zinc hollow-cathode lamp and an air–acetylene flame,using water as the blank.Plot the absorbances of the Standard preparationsversus concentration,in µg per mL,of zinc,and draw the straight line best fitting the three plotted points.From the graph so obtained,determine the concentration,in µg per mL,of zinc in the Assay preparation.Determine the concentration,in mg per mL,of Zn in the Injection taken by the formula: 5C/V, in which Cis the concentration,in µg per mL,of zinc in the Assay preparation;and Vis the volume,in mL,of Injection taken. Auxiliary Information— Staff Liaison:Lawrence Evans,III,Ph.D.,Scientist Expert Committee:(PA6)Pharmaceutical Analysis 6 USP28–NF23Page 2056 Phone Number:1-301-816-8389