Aluminum Sulfate and Calcium Acetate Tablets for Topical Solution
»Aluminum Sulfate and Calcium Acetate Tablets for Topical Solution contain not less than 90.0percent and not more than 110.0percent of the labeled amounts of aluminum sulfate tetradecahydrate [Al2(SO4)3·14H2O]and calcium acetate monohydrate (C4H6CaO4·H2O).
Packaging and storage— Preserve in tight containers,and avoid excessive heat.
Identification—
A: Suspend 2g of ground Tablet powder in 50mLof water,and filter.Mix 2mLof the filtrate with 2mLof water and 2drops of 3Nhydrochloric acid:the solution responds to the ammonium hydroxide test for Aluminum á191ñ.[NOTE—Retain the remaining filtrate for Identification test B.]
B: Aportion of the filtrate retained from Identificationtest Aresponds to the tests for Sulfate á191ñand for Calcium á191ñ.
Uniformity of dosage units á905ñ: meet the requirements for Weight Variation.
pHá791ñ: between 4.0and 4.8,in a solution (2g of ground Tablet powder in 500mLof water).
Loss on drying á731ñ— Dry ground Tablet powder at 150for 15minutes:it loses not more than 18%of its weight.
Assay for aluminum sulfate—
Assay preparation— Finely powder and mix not fewer than 20Tablets.Weigh accurately a portion of the powder,equivalent to about 2.8g of aluminum sulfate,and transfer to a 1000-mLvolumetric flask.Add 100mLof 1.2Nhydrochloric acid and 100mLof water,and heat on a steam bath,with occasional swirling,to dissolve the powder.Allow the solution to cool,dilute with water to volume,and mix.[NOTE—Retain a portion of this Assay preparation for the Assay for calcium acetate.]
Procedure— Transfer 25.0mLof the Assay preparationto a 250-mLconical flask.Add 40.0mLof 0.01Medetate disodium VSand 20mLof acetic acid–ammonium acetate buffer TS,and mix by swirling.Add 50mLof alcohol and 2mLof dithizone TS,and titrate with 0.02Mzinc sulfate VSuntil the color changes from green-violet to a clear rose-pink.Perform a blank determination,substituting 25mLof water for the Assay preparation,and make any necessary correction.Each mLof 0.01Medetate disodium is equivalent to 2.972mg of Al2(SO4)3·14H2O.
Assay for calcium acetate— Transfer 20.0mLof the Assay preparationretained from the Assay for aluminum sulfateto a 125-mLconical flask.With constant stirring,add in the order named,about 0.5mLof trolamine,10mLof ammonia–ammonium chloride buffer TS,and 3drops of a solution prepared by dissolving 500mg of eriochrome black Ttrituration in 10mLof methanol,and titrate with 0.01Medetate disodium VSto a violet endpoint.Each mLof 0.01Medetate disodium is equivalent to 1.762mg of C4H6CaO4·H2O.
Auxiliary Information— Staff Liaison:Behnam Davani,Ph.D.,MBA,Senior Scientist
Expert Committee:(PA7)Pharmaceutical Analysis 7
USP28–NF23Page 97
Phone Number:1-301-816-8394