Sodium Salicylate Tablets
»Sodium Salicylate Tablets contain not less than 95.0percent and not more than 105.0percent of the labeled amount of C7H5NaO3.
Packaging and storage—
Preserve in well-closed containers.
Identification—
A:
Digest a quantity of powdered Tablets,equivalent to about 1g of sodium salicylate,with 20mLof water,and filter:the filtrate responds to the flame test for Sodium á191ñand to the tests for Salicylate á191ñ.
B:
To 10mLof the filtrate obtained in Identificationtest Aadd a slight excess of 3Nhydrochloric acid,collect the precipitate on a filter,wash it with small portions of cold water until the last washing is free from chloride,and dry at about 105
for 1hour:the salicylic acid so obtained melts between 158and 161(see Melting Range or Temperature á741ñ).
for 1hour:the salicylic acid so obtained melts between 158and 161(see Melting Range or Temperature á741ñ).
Dissolution á711ñ—
Medium:
water;900mL.
Apparatus 1:
100rpm.
Time:
45minutes.
Procedure—
Determine the amount of C7H5NaO3dissolved from UVabsorbances at the wavelength of maximum absorbance at about 266nm,using filtered portions of the solution under test,diluted with water,if necessary,in comparison with a Standard solution having a known concentration of Sodium Salicylate in the same medium.
Tolerances—
Not less than 75%(Q)of the labeled amount of C7H5NaO3is dissolved in 45minutes.
Uniformity of dosage units á905ñ:
meet the requirements.
Assay—
Place not less than 20Tablets in a 200-mLvolumetric flask,add 100mLof water,and allow to stand,with frequent agitation,until the tablets disintegrate completely.Dilute with water to volume,and mix.Filter through a dry filter into a dry flask,discarding the first 10mLof the filtrate.Transfer an accurately measured volume of the subsequent filtrate,equivalent to about 500mg of sodium salicylate,to a separator,and dilute with water,if necessary,to make about 25mL.Add 75mLof ether and 10drops of bromophenol blue TS,and titrate with 0.1Nhydrochloric acid VS,mixing the water and ether layers by vigorous shaking until a permanent,pale green color is produced in the water layer.Draw off the water layer into a small flask,wash the ether layer once with 5mLof water,and add this to the water layer.Add 20mLof ether to the combined water solutions,and mix.Continue the titration with vigorous shaking until a permanent,pale green color is produced in the water layer.Each mLof 0.1Nhydrochloric acid is equivalent to 16.01mg of C7H5NaO3.
Auxiliary Information—
Staff Liaison:Daniel K.Bempong,Ph.D.,Scientist
Expert Committee:(PA2)Pharmaceutical Analysis 2
USP28–NF23Page 1794
Phone Number:1-301-816-8143