Bismuth Subsalicylate Magma
»Bismuth Subsalicylate Magma is a suspension of Bismuth Subsalicylate in water that contains not less than 90.0percent and not more than 110.0percent of the labeled amount of C7H5O4Bi.Bismuth Subsalicylate is a basic salt that when dried at 105
for 3hours contains not less than 56.0percent and not more than 59.4percent bismuth and not less than 36.5percent and not more than 39.3percent of total salicylates.
for 3hours contains not less than 56.0percent and not more than 59.4percent bismuth and not less than 36.5percent and not more than 39.3percent of total salicylates.
NOTE—Dry at 105ºfor 3hours to determine the solids content and,after determining the solids content,perform all tests on a portion of the dried magma.
Packaging and storage—
Preserve in tight containers.
Labeling—
The label states that this article is not intended for direct administration to humans or animals.
Identification—
A:
Infrared Absorption á197Mñ.
B:
It meets the requirements of the tests for Bismuth á191ñ.
Other requirements—
It meets the requirements for Limit of nitrate,Limit of free salicylic acid,Limit of copper,lead,and silver,and Limit of soluble bismuthunder Bismuth Subsalicylate.
Assay for bismuth—
Using a quantity of dried Magma,equivalent to about 300mg of bismuth subsalicylate,proceed as directed in the Assay for bismuthunder Bismuth Subsalicylate.
Assay for total salicylates—
Ferric ammonium sulfate solution,Standard stock solution,Standard preparation,and Blank—
Proceed as directed in the Assay for total salicylatesunder Bismuth Subsalicylate.
Assay preparation—
Using a quantity of dried Magma,equivalent to about 52mg of bismuth subsalicylate,proceed as directed for the Assay preparationin the Assay for total salicylatesunder Bismuth Subsalicylate.
Procedure—
Proceed as directed in the Assay for total salicylatesunder Bismuth Subsalicylate.Calculate the percentage of total salicylates in the portion of dried Magma taken by the formula:
10,000(C/W)[(AUr–AUu–B)/(ASr–ASu–B)],
in which Wis the weight,in mg,of dried Magma taken to prepare the Assay preparation;AUris the absorbance of the Reacted assay preparation;AUuis the absorbance of the Unreacted assay preparation;ASris the absorbance of the Reacted standard preparation;ASuis the absorbance of the Unreacted standard preparation;and Bis the difference in the absorption of the Reacted blank solutionand the absorption of the Unreacted blank solution.
Auxiliary Information—
Staff Liaison:Clydewyn M.Anthony,Ph.D.,Scientist
Expert Committee:(PA2)Pharmaceutical Analysis 2
USP28–NF23Page 268
Pharmacopeial Forum:Volume No.28(1)Page 43
Phone Number:1-301-816-8139