Barium Sulfate for Suspension
»Barium Sulfate for Suspension is a dry mixture of Barium Sulfate and one or more suitable dispersing and/or suspending agents.It contains not less than 90.0percent and not more than 110.0percent of the labeled amount of barium sulfate (BaSO4).It may contain one or more suitable colors,flavors,fluidizing agents,and preservatives.
Packaging and storage— Preserve in well-closed containers.
Identification— Ignite a 1-g portion to constant weight:the ignited residue meets the requirements for IdentificationtestsAandBunderBarium Sulfate.
pHá791ñ: between 3.5and 10.0,in a 60%(w/w)aqueous suspension,or constituted for its intended use as directed in the labeling.
Loss on drying á731ñ— Dry it at 105for 4hours:it loses not more than 1.0%of its weight.
Assay— Weigh accurately a quantity of Barium Sulfate for Suspension,equivalent to about 0.60g of barium sulfate (BaSO4),in a tared platinum crucible,and ignite over a low flame until any organic matter is thoroughly carbonized.Cool,cautiously add 0.5mLof nitric acid and 0.5mLof sulfuric acid,and continue the ignition over a low flame until the residue becomes gray in color,then ignite over the full heat of a blast burner.Allow the contents of the crucible to cool to room temperature.
NOTE1—If the specimen contains a silicate,such as bentonite,proceed as follows.Add 10mLof water and 1mLof sulfuric acid to the residue in the crucible,mix,and add 10mLof hydrofluoric acid.Heat gently over a low flame until fumes of sulfur trioxide appear.Add 5mLmore of hydrofluoric acid,heat again over a low flame to the appearance of dense fumes,and continue heating until the sulfuric acid has been completely volatilized.Allow the contents of the crucible to cool.
NOTE2—If the specimen does not contain a silicate,omit the treatment of the specimen with hydrofluoric and sulfuric acids.
Add to the treated or untreated specimen in the platinum crucible 10g of anhydrous sodium carbonate,fuse over a blast burner until a clear melt is obtained,and heat for an additional 30minutes.Proceed as directed in theAssayunderBarium Sulfate,beginning with “Cool,place the crucible in a 400-mLbeaker.”
Auxiliary Information— Staff Liaison:Andrzej Wilk,Ph.D.,Senior Scientific Associate
Expert Committee:(RMI)Radiopharmaceuticals and Medical Imaging Agents
USP28–NF23Page 220
Pharmacopeial Forum:Volume No.28(1)Page 39
Phone Number:1-301-816-8305