Stanozolol Tablets, chemical structure, molecular formula, Reference Standards

Stanozolol Tablets

»Stanozolol Tablets contain not less than 90.0percent and not more than 110.0percent of the labeled amount of stanozolol (C21H32N2O).

Packaging and storage— Preserve in tight,light-resistant containers.

USP Reference standards á11ñ— USP Stanozolol RS.

Identification— Boil an amount of powdered Tablets,equivalent to about 2mg of stanozolol,with 5mLof benzene,filter,and evaporate on a steam bath to dryness.Add 3mLof p-dimethylaminobenzaldehyde TSto the residue:a yellow color develops,which exhibits a green fluorescence under long-wavelength UVlight.

Dissolution á711ñ—

Medium: 0.1Nhydrochloric acid;500mL.

Apparatus 2: 50rpm.

Time: 45minutes.

Determine the amount of C21H32N2Odissolved by employing the following method.

Bromocresol purple solution— Mix 1.0g of bromocresol purple with 1000mLof dilute glacial acetic acid (1in 50),and filter if necessary to obtain a clear solution.

Standard preparations— [NOTE—PrepareStandard preparations on the day of use.]Transfer about 50mg of USP Stanozolol RS,accurately weighed,to a 50-mLvolumetric flask,add 15.0mLof methanol,and mix to dissolve.Add 5.0mLof 1.0Nhydrochloric acid,dilute with water to volume,and mix.Transfer 5.0mLof the resulting solution to a 200-mLvolumetric flask,dilute withDissolution Medium to volume,and mix.Separately pipet 2-mL,4-mL,and 6-mLportions of the solution into three 60-mLseparators,add accurately measured volumes ofDissolution Medium to adjust the volumes in each to 25.0mL,and pipet 25mLofDissolution Medium into a fourth 60-mLseparator.

Procedure— Pipet 25mLof a filtered portion of the solution under test into a 60-mLseparator.To this separator and to each of the four separators containingStandard preparations add 1.0mLofBromocresol purple solution and 10.0mLof chloroform.Insert the stopper in each,shake gently for 1minute,allow the phases to separate,and swirl if necessary to break up emulsions.Transfer the lower chloroform layers to separate 50-mLcentrifuge tubes,insert the glass stoppers,and centrifuge for 5minutes to clarify the solutions.Concomitantly determine the absorbances of the solutions obtained from the solution under test and from theStandard preparation in 1-cm cells,at the wavelength of maximum absorbance at about 420nm,with a suitable spectrophotometer,using chloroform as the blank.Construct a standard plot of absorbances versus the concentrations of the solutions from theStandard preparations.From the plot so obtained,determine the amount of C21H32N2Odissolved in the solution from the solution under test.

Tolerances— Not less than 75%(Q)of the labeled amount of C21H32N2Ois dissolved in 45minutes.

Uniformity of dosage units á905ñ— [NOTE—Maintain the acid concentration at a uniform level in the solutions being compared spectrophotometrically;the same acidic alcohol solution is to be used throughout this procedure.Also,take precautions throughout this procedure to minimize evaporation.]Transfer 1Tablet to a 25-mLvolumetric flask,add 0.5mLof water,and shake to disintegrate.Add about 20mLof alcohol,heat on a steam bath,with occasional swirling,for 10to 15minutes,then cool,dilute with alcohol to volume,and mix.Filter through medium-porosity filter paper,taking precautions to minimize evaporation,discard the first 5mLof the filtrate,and proceed as directed forAssay preparations in theAssay,beginning with “Transfer 5.0mLof the filtrate.”

Assay— [NOTE—Maintain the acid concentration at a uniform level in the solutions being compared spectrophotometrically;the same acidic alcohol solution is to be used throughout this procedure.]

Standard preparations— Dissolve a suitable quantity of USP Stanozolol RS,accurately weighed,in alcohol,and dilute quantitatively and stepwise with alcohol,if necessary,to obtain a stock solution having a known concentration of about 80µg per mL.Transfer 5.0mLof this stock solution to a 10-mLvolumetric flask,dilute with alcohol to volume,and mix to prepare theNeutral standard preparation.Transfer another 5.0-mLportion of the stock solution to a second 10-mLvolumetric flask,dilute with acidic alcohol (1.5mLof hydrochloric acid in 100mLof alcohol)to volume,and mix to prepare theAcidic standard preparation.The concentration of USP Stanozolol RSin theStandard preparations is about 40µg per mL.

Assay preparations— Weigh and finely powder not less than 20Tablets.Transfer an accurately weighed portion of the powder,equivalent to about 4mg of stanozolol,to a 50-mLvolumetric flask,add about 25mLof alcohol,and heat on a steam bath,with frequent swirling,for 15minutes.Cool,dilute with alcohol to volume,mix,filter through medium-porosity filter paper,taking precautions to minimize evaporation,and discard the first 10mLof the filtrate.Transfer 5.0mLof the filtrate to a 10-mLvolumetric flask,dilute with alcohol to volume,and mix to prepare theNeutral assay preparation.Transfer another 5.0-mLportion of the filtrate to a second 10-mLvolumetric flask,dilute with acidic alcohol (1.5mLof hydrochloric acid in 100mLof alcohol)to volume,and mix to prepare theAcidic assay preparation.

Procedure— Concomitantly determine the absorbances of the acidic alcohol solution,theAcidic standard preparation,and theAcidic assay preparation in 1-cm cells at the wavelength of maximum absorbance at about 235nm,with a suitable spectrophotometer,using alcohol,theNeutral standard preparation,and theNeutral assay preparation,respectively,as the blanks.Calculate the quantity,in mg,of C21H32N2Oin the portion of Tablets taken by the formula:

0.1C(AU-AO)/(AS-AO),

in whichCis the concentration,in µg per mL,of USP Stanozolol RSin theStandard preparations;andAU,AS,andAOare the absorbances of theAcidic assay preparation,theAcidic standard preparation,and the acidic alcohol solution,respectively.

Auxiliary Information— Staff Liaison:Clydewyn M.Anthony,Ph.D.,Scientist

Expert Committee:(PA1)Pharmaceutical Analysis 1

USP28–NF23Page 1803

Pharmacopeial Forum:Volume No.28(2)Page 367

Phone Number:1-301-816-8139