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Bismuth Subsalicylate Magma
» Bismuth Subsalicylate Magma is a suspension of Bismuth Subsalicylate in water that contains not less than 90.0 percent and not more than 110.0 percent of the labeled amount of C7H5O4Bi. Bismuth Subsalicylate is a basic salt that when dried at 105 for 3 hours contains not less than 56.0 percent and not more than 59.4 percent bismuth and not less than 36.5 percent and not more than 39.3 percent of total salicylates.
NOTE—Dry at 105º for 3 hours 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 197M.
B: It meets the requirements of the tests for Bismuth 191.
Residual solvents 467: meets the requirements.
(Official January 1, 2007)
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 bismuth under Bismuth Subsalicylate.
Assay for bismuth— Using a quantity of dried Magma, equivalent to about 300 mg of bismuth subsalicylate, proceed as directed in the Assay for bismuth under 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 salicylates under Bismuth Subsalicylate.
Assay preparation— Using a quantity of dried Magma, equivalent to about 52 mg of bismuth subsalicylate, proceed as directed for the Assay preparation in the Assay for total salicylates under Bismuth Subsalicylate.
Procedure— Proceed as directed in the Assay for total salicylates under 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 W is the weight, in mg, of dried Magma taken to prepare the Assay preparation; AUr is the absorbance of the Reacted assay preparation; AUu is the absorbance of the Unreacted assay preparation; ASr is the absorbance of the Reacted standard preparation; ASu is the absorbance of the Unreacted standard preparation; and B is the difference in the absorption of the Reacted blank solution and the absorption of the Unreacted blank solution.
Auxiliary Information— Staff Liaison : Clydewyn M. Anthony, Ph.D., Scientist
Expert Committee : (MDCCA05) Monograph Development-Cough Cold and Analgesics
USP29–NF24 Page 292
Pharmacopeial Forum : Volume No. 28(1) Page 43
Phone Number : 1-301-816-8139