Testosterone Cypionate Injection »Testosterone Cypionate Injection is a sterile solution of Testosterone Cypionate in a suitable vegetable oil.It contains not less than 90.0percent and not more than 110.0percent of the labeled amount of C27H40O3.It may contain a suitable solubilizing agent. Packaging and storage— Preserve in single-dose or multiple-dose containers,preferably of Type Iglass,protected from light. USP Reference standards á11ñ USP Cholesteryl Caprylate RS.USP Testosterone Cypionate RS. 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 105for a few minutes.Spray the plate with a mixture of alcohol and sulfuric acid (3:1),and heat in an oven at 105for 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. Other requirements— It meets the requirements under Injections á1ñ. Assay— Internal standard solution and Standard preparation—Prepare as directed in the Assayunder Testosterone Cypionate. 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 C27H40O3in 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. Auxiliary Information— Staff Liaison:Clydewyn M.Anthony,Ph.D.,Scientist Expert Committee:(PA1)Pharmaceutical Analysis 1 USP28–NF23Page 1876 Phone Number:1-301-816-8139