Identification
Dilute a suitable volume of Injection with chloroform to obtain a solution having a concentration of about 400µg of testosterone cypionate per mL.Prepare a 20-×20-cm thin-layer chromatographic plate (see
Chromatography á621ñ),coated with a 0.25-mm layer of chromatographic siliceous earth,by placing it in a developing chamber containing and equilibrated with a mixture of chloroform and corn oil (90:10),and allowing the solvent front to move about three-fourths of the length of the plate.Remove the plate,and allow the chloroform to evaporate.Apply 10µLeach of the solution under test and of a solution of
USP Testosterone Cypionate RSin chloroform containing about 400µg per mLon the plate,on a line about 2.5cm from the bottom edge and about 1.5cm apart.Place the plate in a developing chamber that contains and has been equilibrated with a mixture of methanol and water (90:10)previously saturated with corn oil.Develop the chromatogram until the solvent front has moved to about 10cm above the line of application.Remove the plate,and heat in an oven at 105

for a few minutes.Spray the plate with a mixture of alcohol and sulfuric acid (3:1),and heat in an oven at 105

for 1to 2minutes.Observe the plate under long-wavelength UVlight:the
RFvalue of the principal spot obtained from the solution under test corresponds to that obtained from the Standard solution.
Assay
Assay preparation
Transfer 1mLof Injection,accurately measured,into a glass-stoppered,50-mLcentrifuge tube.Add 30mLof a mixture of methanol and water (9:1),insert the stopper,and shake for 15minutes.Centrifuge,remove the dilute methanol layer without disturbing the oil,and transfer it to a 200-mLvolumetric flask.Repeat the extraction with three additional 30-mLportions of the dilute methanol,collecting the combined extracts in the volumetric flask.Dilute the combined extracts with the dilute methanol to volume,mix,and chill the contents of the flask to
-8

.Remove the flask from the freezer,and immediately filter a portion of the contents.Allow the filtrate to reach room temperature,transfer a portion of it,equivalent to about 3mg of testosterone cypionate,to a suitable vial,and evaporate to dryness.Add by pipet 3mLof
Internal standard solution,and shake vigorously to dissolve the residue.
Procedure
Proceed as directed for
Procedurein the
Assayunder
Testosterone Cypionate.Calculate the quantity,in mg,of C
27H
40O
3in the portion of Injection taken by the formula:
600(C/V)(RU/RS),
in which
Cis the concentration,in mg per mL,of
USP Testosterone Cypionate RSin the
Standard preparation;and
Vis the volume,in mL,of the filtrate used in the
Assay preparation.