Test solution: 20mg per mL,in chloroform.

Solvent— Use dimethyl sulfoxide.

Internal standard solution— Dissolve 80mg of USP Cholesteryl Caprylate RSin a mixture of methanol and chloroform (4:1)in a 100-mLvolumetric flask,then add the same solvent mixture to volume.

Standard preparation— Weigh accurately about 10mg of USP Testosterone Cypionate RSinto a suitable vial,add by pipet 10mLof Internal standard solution,and mix.

Assay preparation— Prepare as directed for Standard preparation,using an accurately weighed portion of about 10mg of Testosterone Cypionate instead of the Reference Standard.

Procedure— Inject 1µLof the Assay preparationand the Standard preparation,successively,into a suitable gas chromatograph fitted with a flame-ionization detector.Under typical conditions,the instrument contains a 3-mm ×1.2-m glass column packed with 1%(w/w)phase G6on packing S1AB.The column temperature is maintained at 260and the helium carrier gas flows at 50mLper minute.In a suitable chromatogram,the resolution factor,R(see Chromatography á621ñ),is not less than 3between the internal standard and testosterone cypionate peaks,and five replicate injections of a single Standard preparationshow a coefficient of variation of not more than 2%in the peak area ratio of testosterone cypionate to internal standard.Measure the areas under the peaks for testosterone cypionate and cholesteryl caprylate in each chromatogram.Calculate the ratio,RU,of the area of the testosterone cypionate peak to the area of the internal standard peak in the chromatogram from the Assay preparation,and similarly calculate the ratio,RS,in the chromatogram from the Standard preparation.Calculate the quantity,in mg,of C27H40O3in the portion of Testosterone Cypionate taken by the formula: in which Wis the weight,in mg,of USP Testosterone Cypionate RSin the Standard preparation,and the other terms are as defined therein.