Bismuth Subgallate
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Gallic acid bismuth basic salt [99-26-3].
»Bismuth Subgallate is a basic salt which,when dried at 105
for 3hours,contains the equivalent of not less than 52.0percent and not more than 57.0percent of Bi2O3.
for 3hours,contains the equivalent of not less than 52.0percent and not more than 57.0percent of Bi2O3.
Packaging and storage—
Preserve in tight,light-resistant containers.
Identification—
A:
When heated to redness,it at first chars,leaving finally a yellow residue.This residue responds to the tests for Bismuth á191ñ.
B:
Agitate thoroughly about 100mg with an excess of hydrogen sulfide TS,filter,and boil the filtrate to expel the dissolved gas.Cool,and add 1drop of ferric chloride TS:a purplish blue mixture is produced.
Loss on drying á731ñ—
Dry it at 105for 3hours.It loses not more than 7.0%of its weight.
for 3hours.It loses not more than 7.0%of its weight.
Limit of nitrate—
Mix about 100mg with 5mLof 2Nsulfuric acid and 5mLof ferrous sulfate TS,filter the mixture,and carefully superimpose the filtrate,without mixing,on 5mLof sulfuric acid,in a test tube:no reddish brown color appears at the zone of contact of the two liquids.
Arsenic—
Triturate 400mg with an equal weight of calcium hydroxide,and ignite.Dissolve the residue in 5mLof 3Nhydrochloric acid:the solution without further treatment meets the requirements of the test for Arsenic á211ñ(7.5ppm).
Copper,Lead,and Silver—
Ignite 3g in a porcelain crucible,cool,and cautiously add,dropwise,just sufficient nitric acid to dissolve the residue upon warming.Evaporate the solution to dryness,again ignite,and cool.Cautiously dissolve the residue in just sufficient nitric acid with the aid of gentle heat,concentrate the solution to about 4mL,pour it into 100mLof water,filter,evaporate the filtrate on a steam bath to 20mL,again filter,and divide this filtrate into portions of 5mLeach.Using these several portions as the test liquid,proceed as directed for Copper,Lead,and Silverunder Bismuth Subnitrate.The specified results are obtained.
Limit of alkalies and alkaline earths—
Boil 1.0g with 20mLof a mixture of equal volumes of 6Nacetic acid and water,cool,and filter.Precipitate the bismuth from the filtrate by the addition of hydrogen sulfide,boil the mixture,and filter.Add 5drops of sulfuric acid to the filtrate,evaporate to dryness,and ignite to constant weight:the weight of the residue does not exceed 5mg (0.5%).
Free gallic acid—
Shake 1.0g with 20mLof alcohol for 1minute,filter and evaporate the filtrate to dryness on a steam bath,and dry the residue at 105for 1hour:the weight of the residue does not exceed 5mg (0.5%).
for 1hour:the weight of the residue does not exceed 5mg (0.5%).
Assay—
Dry about 1g of Bismuth Subgallate at 105for 3hours,then weigh accurately and ignite in a porcelain crucible.Allow it to cool and add nitric acid to the residue,dropwise,warming until complete solution has been effected.Evaporate the solution to dryness and carefully ignite the residue to constant weight.From the weight of the residue so obtained,determine the percentage of Bi2O3in the portion of Bismuth Subgallate taken.
for 3hours,then weigh accurately and ignite in a porcelain crucible.Allow it to cool and add nitric acid to the residue,dropwise,warming until complete solution has been effected.Evaporate the solution to dryness and carefully ignite the residue to constant weight.From the weight of the residue so obtained,determine the percentage of Bi2O3in the portion of Bismuth Subgallate taken.
Auxiliary Information—
Staff Liaison:Lawrence Evans,III,Ph.D.,Scientist
Expert Committee:(PA6)Pharmaceutical Analysis 6
USP28–NF23Page 266
Phone Number:1-301-816-8389