Zinc Chloride Injection »Zinc Chloride Injection is a sterile solution of Zinc Chloride 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,preferably of Type Ior Type IIglass. Labeling— Label the Injection to indicate that it is to be diluted with Water for Injection or other suitable fluid to appropriate strength prior to administration. USP Reference standards á11ñ USP Endotoxin RS. Identification— The Assay preparationprepared as directed in the Assayexhibits an absorption maximum at about 213.8nm,when determined as directed in the Assay. Bacterial endotoxins á85ñ It contains not more than 25.0USP Endotoxin Units per mg of zinc. pHá791ñ: between 1.5and 2.5. 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 obtain solutions of suitable concentrations adaptable to the linear or working range of the instrument.] Sodium chloride solution— Dissolve 450mg of sodium chloride in water,dilute with water to 500mL,and mix. Standard preparations— Transfer 3.11g of zinc oxide,accurately weighed,to a 250-mLvolumetric flask,add 80mLof 1Nsulfuric acid,warm to dissolve,cool,dilute with water to volume,and mix.This stock solution contains 10.0mg of zinc per mL.Dilute an accurately measured volume of this solution quantitatively with water to obtain a solution containing 125µg of zinc per mL.Transfer 2.0,3.0,and 4.0mL,respectively,of this solution to three separate 500-mLvolumetric flasks,each containing 5mLof Sodium chloride solution,dilute the contents of each flask with water to volume,and mix.These Standard preparationscontain,respectively,0.50,0.75,and 1.0µg of zinc per mL. Assay preparation— Transfer an accurately measured volume of Injection,equivalent to about 5mg of zinc,to a 500-mLvolumetric flask,dilute with water to volume,and mix.Transfer 10.0mLof this solution to a 100-mLvolumetric flask.From the labeled amount of sodium chloride,if any,in the Injection,calculate the amount,in mg,of sodium chloride in the 10.0-mLportion and add sufficient Sodium chloride solutionto bring the total sodium chloride content of the 100-mLvolumetric flask to 9mg.Dilute with water to volume,and mix. Procedure— Concomitantly determine the absorbances of the Standard preparationsand the Assay preparationat the zinc emission line at 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.Calculate the quantity,in mg,of zinc in each mLof 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 2053 Phone Number:1-301-816-8389