Azathioprine Tablets
»Azathioprine Tablets contain not less than 93.0percent and not more than 107.0percent of the labeled amount of azathioprine (C9H7N7O2S).
Packaging and storage— Protect from light.
Identification— Tablets meet the requirement of the Thin-layer Chromatographic Identification Test á201ñ,the test solution being the filtrate obtained by shaking a quantity of powdered Tablets,equivalent to about 200mg of azathioprine,with 10mLof 6Nammonium hydroxide,the Standard solution being a solution of USP Azathioprine RSin 6Nammonium hydroxide containing 20mg per mL,and 5-µLportions of each solution being spotted on a thin-layer chromatographic plate coated with a 0.25-mm layer of microcrystalline cellulose,and butyl alcohol,previously saturated with 6Nammonium hydroxide,being used for developing.
Dissolution á711ñ—
Medium: water;900mL.
Apparatus 2: 50rpm.
Time: 30minutes.
Procedure— Determine the amount of C9H7N7O2Sdissolved from UVabsorbances at the wavelength of maximum absorbance at about 280nm of 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 Azathioprine RSin the same medium.
Tolerances— Not less than 75%(Q)of the labeled amount of C9H7N7O2Sis dissolved in 30minutes.
Uniformity of dosage units á905ñ: meet the requirements.
Assay—
Mobile phase— Dissolve 1.1g of sodium 1-heptanesulfonate in 700mLof water,add 300mLof methanol,and mix.Adjust the solution with 1Nhydrochloric acid to a pHof 3.5.Filter the solution through a 0.8-µm solvent-resistant membrane,and degas,making adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).
Standard preparation— Transfer about 25mg of USP Azathioprine RS,accurately weighed,to a 50-mLvolumetric flask.Add about 15mLof methanol and 0.5mLof ammonium hydroxide to the flask,swirl,and sonicate for 2minutes.Dilute with methanol to volume,and mix.Transfer 10.0mLof this solution to a 50-mLvolumetric flask,dilute with water to volume,and mix.
Assay preparation— Weigh and finely powder not fewer than 20Tablets.Accurately weigh a portion of the powder,equivalent to about 50mg of azathioprine,and transfer to a 100-mLvolumetric flask.Add 25mLof methanol and 1.0mLof ammonium hydroxide to the flask,swirl,and sonicate for 2minutes.Dilute with methanol to volume,and mix.Allow the excipients to settle,transfer 10.0mLof the supernatant to a 50-mLvolumetric flask,dilute with water to volume,and mix.
Chromatographic system (see Chromatography á621ñ)—The liquid chromatograph is equipped with a 254-nm detector and a 4-mm ×30-cm column that contains packing L1.The flow rate is about 2mLper minute.Chromatograph the Standard preparation,and record the peak responses as directed for Procedure:the column efficiency is not less than 800theoretical plates,the tailing factor for the azathioprine peak is not more than 1.5,and the relative standard deviation for replicate injections is not more than 2.0%.
Procedure— Separately inject equal volumes (about 10µL)of the Standard preparationand the Assay preparationinto the chromatograph,record the chromatograms,and measure the responses for the major peaks.Calculate the quantity,in mg,of azathioprine (C9H7N7O2S)in the portion of Tablets taken by the formula:
500(C)(rU/rS),
in which Cis the concentration,in mg per mL,of USP Azathioprine RSin the Standard preparation,and rUand rSare the peak responses for azathioprine obtained from the Assay preparationand the Standard preparation,respectively.
Auxiliary Information— Staff Liaison:Lawrence Evans,III,Ph.D.,Scientist
Expert Committee:(PA6)Pharmaceutical Analysis 6
USP28–NF23Page 207
Phone Number:1-301-816-8389