Test solution: 20 mg per mL, in chloroform.

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

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

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

Procedure— Inject 1 µL of the Assay preparation and 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 G6 on packing S1AB. The column temperature is maintained at 260 and the helium carrier gas flows at 50 mL per minute. In a suitable chromatogram, the resolution factor, R (see Chromatography 621), is not less than 3 between the internal standard and testosterone cypionate peaks, and five replicate injections of a single Standard preparation show 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 C27H40O3 in the portion of Testosterone Cypionate taken by the formula: in which W is the weight, in mg, of USP Testosterone Cypionate RS in the Standard preparation, and the other terms are as defined therein.