Disintegration á701ñ
Place 1Tablet in each of the six tubes of the basket,and if the Tablet has a soluble external coating,immerse the basket in water at room temperature for 5minutes.Operate the apparatus,using simulated gastric fluid TSmaintained at 37±2

as the immersion fluid.After 30minutes of operation in simulated gastric fluid TS,lift the basket from the fluid,and observe the Tablets.If the Tablets have not disintegrated completely,substitute simulated intestinal fluid TSmaintained at 37±2

as the immersion fluid,and continue the test for a total period of time,including previous exposure to water and simulated gastric fluid TS,equal to 45minutes.Lift the basket from the fluid,and observe the Tablets:all of the Tablets have disintegrated completely.If 1or 2Tablets fail to disintegrate completely,repeat the test on 12additional Tablets:not less than 16of the total of 18Tablets tested disintegrate completely.
Assay
Internal standard solution
Transfer about 20mg of
USP Propylparaben RSto a 50-mLvolumetric flask,dissolve in and dilute with alcohol to volume,and mix.
Standard preparation
Dissolve in alcohol a suitable quantity of
USP Chlorambucil RS,accurately weighed,and prepare,by quantitative dilution,a solution in alcohol having a known concentration of about 1mg per mL.Transfer 2.0mLof the solution to a 100-mLvolumetric flask containing about 50mLof alcohol and,while gently swirling,add 5.0mLof 0.1Nhydrochloric acid and 2.0mLof
Internal standard solution.Dilute with alcohol to volume,and mix.
Assay preparation
Weigh and finely powder not less than 20Tablets.Transfer an accurately weighed portion of the powder,equivalent to about 2mg of chlorambucil,to a 100-mLvolumetric flask containing about 50mLof alcohol and,while gently swirling,add 5.0mLof 0.1Nhydrochloric acid and 2.0mLof Internal standard solution.Sonicate for 5minutes,dilute with alcohol to volume,and mix.Filter through a medium-porosity,sintered-glass filtering funnel,maintaining reduced pressure for the minimum necessary time in order to avoid solvent loss of evaporation.
Mobile phase
Mix 500mLof alcohol with 1.0mLof glacial acetic acid in a 1-liter volumetric flask,dilute with water to volume,and mix.The alcohol concentration may be varied to meet system suitability requirements and to provide a suitable elution time for chlorambucil.Degas the solution at a pressure of approximately 250mm of mercury for 2minutes.
Chromatographic system
Typically,a high-pressure liquid chromatograph,operated at room temperature,is fitted with a 25-or 30-cm ×2-mm stainless steel column packed with spherical silica microbeads,5µm to 10µm in diameter,to which is bonded a nominal 10%or 20%(w/w)octadecyl silane.The mobile phase is maintained at a flow rate capable of giving the required resolution (see System suitability test)and a suitable elution time.An UVdetector that monitors absorption at the 254-nm wavelength is used.
System suitability test
Chromatograph 6to 10injections of the
Standard preparation,and measure the peak responses as directed under
Procedure.Calculate the response factor,
PS,and the resolution factor,
R(see
Chromatography á621ñ).The response factor for 6to 8injections does not vary by more than 2.0%relative standard deviation and the resolution factor is not less than 2.0.
Procedure
Introduce equal volumes (10to 12µL)of the
Standard preparationand the
Assay preparationinto the high-pressure liquid chromatograph by means of a suitable sampling valve or high-pressure microsyringe,and measure the peak responses at identical retention times obtained with each preparation.Calculate the quantity,in mg,of C
14H
19Cl
2NO
2in the portion of Tablets taken by the formula:
0.1C(PU/PS),
in which
Cis the concentration,in µg per mL,of
USP Chlorambucil RSin the
Standard preparation,and
PUand
PSare the response factors of the
Assay preparationand the
Standard preparation,respectively.