Internal standard solution— Dissolve 100mg of n-octacosane in 200mLof chloroform.

Standard preparation— Transfer about 50mg of USP Oxandrolone RS,accurately weighed,to a 100-mLvolumetric flask,dissolve in Internal standard solution,dilute with Internal standard solutionto volume,and mix.

Assay preparation— Weigh and finely powder not less than 20Tablets.Transfer an accurately weighed portion of the powder,equivalent to about 5mg of oxandrolone,to a suitable container,add 10.0mLof Internal standard solution,and shake by mechanical means for 30minutes.Filter through Whatman No.2filter paper,or equivalent,discarding the first 5mLof the filtrate.

Procedure— Inject separately 2-µLportions of the Standard preparationand the Assay preparationinto a suitable gas chromatograph equipped with a flame-ionization detector (see Chromatography á621ñ)and a 2-m ×4-mm glass column,packed with 3percent methylsilicone oil on 80-to 100-mesh acid-,base-,and water-washed,flux-calcined,silanized siliceous earth.The column is maintained at about 250,the injection port is maintained at about 290,and the detector block is maintained at about 300;helium is used as the carrier gas at a flow rate of about 60mLper minute.Calculate the quantity,in mg,of C19H30O3in the portion of Tablets taken by the formula: in which Cis the concentration,in mg per mL,of USP Oxandrolone RSin the Standard preparation,and RUand RSare the ratios of the peak heights of the oxandrolone peak and the internal standard peak from the Assay preparationand the Standard preparation,respectively.