Thiopental Sodium for Injection »Thiopental Sodium for Injection is a sterile mixture of Thiopental Sodium and anhydrous Sodium Carbonate as a buffer.It contains not less than 93.0percent and not more than 107.0percent of the labeled amount of C11H17N2NaO2S. Packaging and storage— Preserve in Containers for Sterile Solidsas described under Injections á1ñ,preferably of Type IIIglass. USP Reference standards á11ñ USP Thiopental RS.USP Endotoxin RS. Completeness of solution á641ñ Mix 800mg with 10mLof carbon dioxide-free water:after 1minute,the solution is clear and free from undissolved solid. Constituted solution— At the time of use,it meets the requirements for Constituted Solutionsunder Injections á1ñ. Bacterial endotoxins á85ñ It contains not more than 1.0USP Endotoxin Unit per mg of thiopental sodium. pHá791ñ: between 10.2and 11.2,in the solution prepared in the test for Completeness of solution. Other requirements— It responds to the Identificationtests and meets the requirements of the test for Heavy metalsunder Thiopental Sodium.It meets also the requirements for Sterility Tests á71ñ,Uniformity of Dosage Units á905ñ,and for Labelingunder Injections á1ñ. Assay— Dissolve the contents of 10containers of Thiopental Sodium for Injection in sufficient water,diluting to an accurately measured volume,to obtain a solution containing about 50mg of thiopental sodium per mL.Dilute this solution quantitatively and stepwise with sodium hydroxide solution (1in 250)to obtain a solution having a concentration of about 5µg of thiopental sodium per mL.Proceed as directed in the Assayunder Thiopental Sodium,beginning with “Dissolve an accurately weighed quantity of USP Thiopental RS.”Calculate the average quantity,in mg,of C11H17N2NaO2Sin each container of Thiopental Sodium for Injection taken by the formula: VC(1.091AU/AS), in which Vis the volume,in mL,of the solution prepared to contain about 50mg of thiopental sodium per mL,Cis the concentration,in µg per mL,of USP Thiopental RSin the Standard solution,1.091is the ratio of the molecular weight of thiopental sodium to that of thiopental,and AUand ASare the absorbances of the solution of Thiopental Sodium for Injection and the Standard solution,respectively. Auxiliary Information— Staff Liaison:Karen A Russo,Ph.D.,Scientist Expert Committee:(PA1)Pharmaceutical Analysis 1 USP28–NF23Page 1915 Phone Number:1-301-816-8379