Probenecid Tablets
»Probenecid Tablets contain not less than 93.0percent and not more than 107.0percent of the labeled amount of C13H19NO4S.
Packaging and storage—
Preserve in well-closed containers.
Identification—
B:
Finely powder a quantity of Tablets,equivalent to about 500mg of probenecid,triturate the powder with alcohol,and filter.Evaporate the filtrate to about 20mL,cool,acidify with hydrochloric acid until acid to litmus,remove the crystals by filtration,and recrystallize from diluted alcohol:the probenecid so obtained melts between 196
and 200,as determined by the method for Class Iaunder Melting Range or Temperature á741ñ,and responds to Identificationtest Aunder Probenecid.
and 200,as determined by the method for Class Iaunder Melting Range or Temperature á741ñ,and responds to Identificationtest Aunder Probenecid.
Dissolution á711ñ—
Medium:
simulated intestinal fluid TS,prepared without pancreatin,pH7.5±0.1;900mL.
Apparatus 2:
75rpm.
Time:
30minutes.
Procedure—
Determine the amount of C13H19NO4Sdissolved by employing UVabsorption at the wavelength of maximum absorbance at about 244nm on filtered portions of the solution under test,suitably diluted with 0.1Nsodium hydroxide,if necessary,in comparison with a Standard solution having a known concentration of USP Probenecid RS.
Tolerances—
Not less than 80%(Q)of the labeled amount of C13H19NO4Sis dissolved in 30minutes.
Uniformity of dosage units á905ñ:
meet the requirements.
Assay—
Weigh and finely powder not less than 20Tablets.Weigh accurately a portion of the powder,equivalent to about 100mg of probenecid,and transfer to a 250-mLvolumetric flask.Add chloroform to volume,and mix.Filter a portion of the chloroform solution,discarding the first 20to 25mLof the filtrate,and pipet 5mLof the filtrate into a 125-mLseparator containing 10mLof chloroform.Extract the chloroform layer with four 15-mLportions of sodium carbonate solution (1in 100).Render the combined extracts distinctly acid with 5Nhydrochloric acid,and extract with four 20-mLportions of chloroform,filtering each extract through a small pledget of cotton into a 100-mLvolumetric flask.Wash the cotton filter with 10mLof chloroform,add chloroform to volume,and mix.Dissolve an accurately weighed quantity of USP Probenecid RSin chloroform,and dilute quantitatively and stepwise with chloroform to obtain a Standard solution having a known concentration of about 20µg per mL.Concomitantly determine the absorbances of both solutions in 1-cm cells at the wavelength of maximum absorbance at about 257nm,with a suitable spectrophotometer,using chloroform as the blank.Calculate the quantity,in mg,of C13H19NO4Sin the portion of Tablets taken by the formula:
5C(AU/AS),
in which Cis the concentration,in µg per mL,of USP Probenecid RSin the Standard solution;and AUand ASare the absorbances of the solution from the Tablets and the Standard solution,respectively.
Auxiliary Information—
Staff Liaison:Elena Gonikberg,Ph.D.,Scientist
Expert Committee:(PA4)Pharmaceutical Analysis 4
USP28–NF23Page 1621
Pharmacopeial Forum:Volume No.28(2)Page 347
Phone Number:1-301-816-8251