Bismuth Subsalicylate Tablets
» Bismuth Subsalicylate Tablets contain not less than 90.0 percent and not more than 110.0 percent of the labeled amount of bismuth subsalicylate (C7H5BiO4).
Packaging and storage Preserve in tight containers. Avoid excessive heat (over 40).
Labeling Label chewable Tablets to indicate that they are to be chewed before swallowing.
A: It meets the requirements of the tests for Bismuth 191.
Disintegration 701: 10 minutes. [noteThis test does not apply for Tablets labeled as chewable.]
Standard preparation Transfer about 500 mg of bismuth, accurately weighed, to a 200-mL volumetric flask, dissolve in 12 mL of nitric acid, and dilute with 0.01 N nitric acid to volume. Transfer 10.0 mL of the solution so obtained into a 500-mL volumetric flask, and dilute with 1 N nitric acid to volume to obtain a concentration of 50 µg of bismuth per mL.
Assay preparation Transfer an accurately weighed portion of finely powdered Tablets, equivalent to about 90 mg of bismuth subsalicylate, to a 200-mL volumetric flask, add about 150 mL of 1 N nitric acid, and sonicate for 2 minutes. Dilute with 1 N nitric acid to volume. Transfer 20.0 mL of the solution so obtained to a 100-mL volumetric flask, and dilute with 1 N nitric acid to volume. Centrifuge a portion at 4500 rpm for at least 10 minutes.
Procedure Transfer 10.0 mL, accurately measured, of the Assay preparation and the Standard preparation to separate 50.0-mL volumetric flasks. Add 10.0 mL of 10% ascorbic acid solution and 25.0 mL of 20% potassium iodide solution into each volumetric flask, and dilute with 1 N nitric acid to volume. Concomitantly determine the absorbance of the solutions at the wavelength of maximum absorbance at about 463 nm with a suitable spectrophotometer using the combined reagent solutions as the blank. Calculate the quantity, in mg, of bismuth subsalicylate (C7H5BiO4) in the portion of Tablets taken by the formula:
(362.09/208.98)(CD)(AU / AS)in which, 362.09 and 208.98 are the molecular weights of bismuth subsalicylate and bismuth, respectively; C is the concentration, in mg per mL, of bismuth in the Standard preparation; D is the dilution factor of the Assay preparation; and AU and AS are the absorbances of the solutions from the Assay preparation and the Standard preparation, respectively.
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USP32NF27 Page 1689Pharmacopeial Forum: Volume No. 32(5) Page 1440