Ethionamide Tablets
»Ethionamide Tablets contain not less than 95.0percent and not more than 110.0percent of the labeled amount of C8H10N2S.
Packaging and storage— Preserve in tight containers.
Identification—
A: The solution of Tablets employed for measurement of absorbance in the Assayexhibits an absorbance maximum at 290±2nm.
B: Digest a quantity of powdered Tablets,equivalent to about 1g of ethionamide,with 50mLof methanol,and filter through a medium-porosity,sintered-glass funnel.Evaporate the filtrate on a steam bath to dryness:the residue so obtained melts between 155and 164.
Dissolution á711ñ—
Medium: 0.1Nhydrochloric acid;900mL.
Apparatus 1: 100rpm.
Time: 45minutes.
Procedure— Determine the amount of C8H10N2Sdissolved by employing UVabsorption at the wavelength of maximum absorbance at about 274nm on filtered portions of the solution under test,suitably diluted with Medium,if necessary,in comparison with a Standard solution having a known concentration of USP Ethionamide RSin the same Medium.
Tolerances— Not less than 75%(Q)of the labeled amount of C8H10N2Sis dissolved in 45minutes.
Uniformity of dosage units á905ñ: meet the requirements.
Assay— Weigh and finely powder not less than 20Tablets.Transfer an accurately weighed portion of the powder,equivalent to about 100mg of ethionamide,to a medium-porosity,sintered-glass funnel that is fitted into a 250-mLsuction flask.Extract the specimen by stirring it with successive 10-mLportions of methanol,using a total of about 100mLof solvent,drawing off each portion of liquid with gentle suction before adding the next portion.Transfer the combined methanol extracts to a 250-mLvolumetric flask,dilute with methanol to volume,and mix.Proceed as directed in the Assayunder Ethionamide,beginning with “Transfer a 5-mLaliquot.”Calculate the quantity,in mg,of C8H10N2Sin the portion of Tablets taken by the formula:
10C(AU/AS),
in which Cis the concentration,in µg per mL,of USP Ethionamide RSin the Standard solution,calculated on the anhydrous basis,and AUand ASare the absorbances of the solution of Ethionamide Tablets and the Standard solution,respectively.
Auxiliary Information— Staff Liaison:Behnam Davani,Ph.D.,MBA,Senior Scientist
Expert Committee:(PA7)Pharmaceutical Analysis 7
USP28–NF23Page 791
Phone Number:1-301-816-8394