Testosterone Enanthate Injection »Testosterone Enanthate Injection is a sterile solution of Testosterone Enanthate in a suitable vegetable oil.It contains not less than 90.0percent and not more than 110.0percent of the labeled amount of C26H40O3. Packaging and storage— Preserve in single-dose or multiple-dose containers,preferably of Type Iglass. USP Reference standards á11ñ USP Testosterone Enanthate RS. Identification— Dilute a suitable volume of Injection with chloroform to obtain a solution having a concentration of about 400µg of testosterone enanthate per mL.Proceed as directed in the Identificationtest under Testosterone Cypionate Injection,beginning with “Prepare a 20-×20-cm thin-layer chromatographic plate,”but using USP Testosterone Enanthate RS.The RFvalue of the principal spot obtained from the solution under test corresponds to that obtained from the Reference Standard solution. Other requirements— It meets the requirements under Injections á1ñ. Assay— Chromatographic solvent— Equilibrate,by shaking in a separator,95mLof alcohol,5mLof water,and 50mLof chromatographic n-heptane.Allow the layers to separate. Isoniazid reagent— Dissolve 375mg of isoniazid and 0.47mLof hydrochloric acid in 500mLof methanol. Standard preparation— Dissolve a suitable quantity of USP Testosterone Enanthate RS,accurately weighed,in methanol,and dilute quantitatively and stepwise with methanol to obtain a solution having a known concentration of about 40µg per mL. Assay preparation— Transfer to a 10-mLvolumetric flask an accurately measured volume of Injection,equivalent to about 100mg of testosterone enanthate,add chromatographic n-heptane to volume,and mix.Pipet 5mLof this solution into a 100-mLvolumetric flask,add chromatographic n-heptane to volume,and mix. Procedure— Mix in a beaker 3g of silanized chromatographic siliceous earth and 3mLof the upper layer of the Chromatographic solvent.Pack the mixture into a 250-×25-mm chromatographic tube that contains a small pledget of glass wool above the stem constriction.Mix in a beaker 3g of silanized chromatographic siliceous earth and 2.0mLof Assay preparation,transfer the mixture to the tube,and pack.Dry-wash the beaker with 1g of silanized chromatographic siliceous earth,and transfer to the tube.Place a small pad of glass wool above the column packing.Pass 35mLof the lower layer of the Chromatographic solventthrough the column,and collect the eluate in a 50-mLvolumetric flask.Add alcohol to volume,and mix.Pipet 10mLof the resulting solution into a glass-stoppered,50-mLconical flask,and evaporate on a water bath to dryness.Pipet 5mLof methanol into the flask,and swirl to dissolve the residue.Pipet 5mLof Standard preparationinto a similar flask.To each flask add 10.0mLof Isoniazid reagent,mix,and allow to stand for about 45minutes.Concomitantly determine the absorbances of both solutions at the wavelength of maximum absorbance at about 380nm,with a suitable spectrophotometer,using as a blank 5mLof methanol that has been treated similarly with Isoniazid reagent.Calculate the quantity,in mg,of C26H40O3in each mLof the Injection taken by the formula: 2.5(C/V)(AU/AS), in which Cis the concentration,in µg per mL,of USP Testosterone Enanthate RSin the Standard preparation;Vis the volume,in mL,of Injection taken;and AUand ASare the absorbances of the solutions from the Assay preparationand the Standard preparation,respectively. Auxiliary Information— Staff Liaison:Clydewyn M.Anthony,Ph.D.,Scientist Expert Committee:(PA1)Pharmaceutical Analysis 1 USP28–NF23Page 1877 Phone Number:1-301-816-8139