Standard solution: 5 mg per mL in chloroform.

Test solution— Transfer a portion of finely powdered Tablets, equivalent to about 20 mg of oxandrolone, to a 50-mL stoppered centrifuge tube, add 4 mL of chloroform, shake by mechanical means for 10 minutes, centrifuge for about 15 minutes, and filter a portion of the chloroform layer.

Application volume: 10 µL.

Developing solvent system: a mixture of chloroform and methanol (19:1).

Procedure— Locate the spots on the plate by lightly spraying with dilute sulfuric acid (1 in 2) and heating on a hot plate or under a lamp until spots appear: the RF value of the principal spot obtained from the Test solution corresponds to that obtained from the Standard solution.

Medium: a solution of water and isopropanol (7:3); 500 mL.

Apparatus 2: 100 rpm.

Time: 60 minutes.

Internal standard solution— Dissolve accurately weighed quantities of 17-methyltestosterone, and dilute quantitatively, and stepwise if necessary, with acetonitrile to obtain a solution having a concentration of about 0.2 mg per mL (for Tablets with a 2.5-mg label claim) and about 0.8 mg per mL (for Tablets with a 10-mg label claim).

Standard solution— Dissolve an accurately weighed quantity of USP Oxandrolone RS, and dilute quantitatively, and stepwise if necessary, with acetonitrile to obtain a solution having a concentration of about 1 mg per mL.

Working standard solution— For Tablets labeled to contain 2.5 mg: combine 100 µL of the Standard solution, 400 µL of the Internal standard solution, and 1500 µL of acetonitrile. For Tablets labeled to contain 10 mg: combine 100 µL of the Standard solution, 100 µL of the Internal standard solution, and 1800 µL of acetonitrile.

Test solution— Withdraw 25 mL of the solution under test from the vessel. Pass through a 0.45-µm polytef filter. Transfer 20 mL of the filtrate to a separatory funnel, add 400 µL of the Internal standard solution, 40 mL of a 10% potassium chloride solution, and 8 mL of chloroform. In separate separatory funnels, prepare an extraction blank and an internal standard blank in a similar manner using 20 mL of filtered Medium in place of the solution under test and excluding the Internal standard solution from the extraction blank. Shake each funnel, and allow the layers to separate. Collect the lower chloroform layer. Repeat the extraction procedure one more time. Evaporate the solvents under a stream of nitrogen at 45 until just dry. Reconstitute the dried residue with 2 mL of acetonitrile (for Tablets with a 2.5-mg label claim) or with 8 mL of acetonitrile (for Tablets with a 10-mg label claim), and sonicate for 10 minutes.

Chromatographic system (see Chromatography 621)— The gas chromatograph is equipped with a flame-ionization detector and a 0.53-mm × 30-m column coated with a 0.5-µm phase G27. The carrier gas is helium, flowing at a rate of about 16.8 mL per minute. The injection port and detector temperatures are maintained at 190 and 320, respectively. The chromatograph is programmed as follows. Upon injection, the column temperature is increased at a rate of 25 per minute to 280, and maintained at 280 for 3 minutes. Then the column temperature is increased at a rate of 10 per minute to 320, and maintained at 320 for 3 minutes. Chromatograph the acetonitrile, the extraction blank, and the internal standard blank, and record the peak responses as directed for Procedure: the tailing factor is not more than 1.5. Make two injections of the Working standard solution, and record the peak responses. The average oxandrolone/Internal standard solution peak area percent comparison is between 98.0% and 102.0%. The resolution, R, between the oxandrolone peak and the nearest eluting peak is equal to or greater than 1.5.

Procedure— Separately inject equal volumes (0.5 µL) of the Working standard solution and the Test solution into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the percentage of C19H30O3 released by the formula: in which CS is the concentration, in mg per mL, of oxandrolone in the Standard solution; sample ratio is the area ratio of oxandrolone to 17-methyltestosterone in the sample injection for each Test solution; VUF is the final volume, in mL, of the sample after reconstitution of the dry residue; 500 is the volume, in mL, of Medium; 100 is the conversion factor to percentage; standard ratio is the mean area ratio of oxandrolone to 17-methyltestosterone in all injections of the Standard solution; VUI is the initial sample volume, in mL, used in the extraction; and LC is the Tablet label claim, in mg.

Tolerances— Not less than 75% (Q) of the labeled amount of oxandrolone (C19H30O3) is dissolved in 60 minutes.

Medium: 1% polysorbate 80 in water; 500 mL, deaerated.

Apparatus 2: 100 rpm.

Time: 120 minutes.

Mobile phase— Prepare a filtered and degassed mixture of water and acetonitrile (55:45). Make adjustments if necessary (see System Suitability under Chromatography 621).

Standard stock solution— Transfer about 20 mg of USP Oxandrolone RS, accurately weighed, to a 200-mL volumetric flask. Add about 20 mL of acetonitrile, and sonicate to dissolve. Dilute with Medium to volume, and mix.

Working standard solution— Quantitatively dilute the Standard stock solution with Medium to obtain a solution having a final concentration of about 5 µg per mL for Tablets with a label claim of 2.5 mg, or a final concentration of about 20 µg per mL for Tablets with a label claim of 10 mg.

Test solution— Withdraw about 10 mL of the solution under test from the vessel. Centrifuge in a glass tube at 2000 rpm for 10 minutes.

Chromatographic system (see Chromatography 621)— The liquid chromatograph is equipped with a refractive index detector and a 4.6-mm × 25-cm column that contains 5-µm packing L1. The column is maintained at 30, and the detector is maintained at 50. The flow rate is about 1.5 mL per minute. Chromatograph the Working standard solution, and record the peak responses as directed for Procedure: the tailing factor is not more than 2.0; the column efficiency is not less than 4000 theoretical plates; and the relative standard deviation for replicate injections is not more than 5.0%.

Procedure— Separately inject equal volumes (about 100 µL) of the Working standard solution and the Test solution into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the percentage of C19H30O3 released by the formula: in which rU and rS are the peak responses obtained from the Test solution and Working standard solution, respectively; CS is the concentration, in mg per mL, of the Working standard solution; D is the dilution factor of the Test solution; 500 is the volume, in mL, of Medium; 100 is the conversion factor to percentage; and LC is the Tablet label claim, in mg.

Tolerances— Not less than 65% (Q) of the labeled amount of C19H30O3 is dissolved in 120 minutes.

Medium: 0.1 N hydrochloric acid containing 0.75% of sodium lauryl sulfate; 500 mL for Tablets labeled to contain 2.5 mg, 900 mL for Tablets labeled to contain 10 mg, deaerated with helium.

Apparatus 2: 75 rpm.

Time: 90 minutes.

Mobile phase— Prepare a filtered and degassed mixture of water and acetonitrile (65:35). Make adjustments if necessary (see System Suitability under Chromatography 621).

Standard stock solution— Transfer about 20 mg, accurately weighed, of USP Oxandrolone RS to a 100-mL volumetric flask. Dissolve in approximately 5 mL of acetonitrile, and sonicate for 10 minutes. Dilute with Medium to volume, and mix.

Working standard solution— Transfer 8.0 mL of the Standard stock solution to a 200-mL volumetric flask, dilute with Medium to volume, and mix.

Test solution— Pass the solution under test through a suitable filter having a porosity of 0.45 µm.

Chromatographic system— The liquid chromatograph is equipped with a refractive index detector and a 4.6-mm × 30-cm column that contains 5-µm packing L1. The flow rate is about 1.0 mL per minute. The temperatures of the detector and the column are both maintained at 35. Chromatograph the Working standard solution, and record the peak responses as directed for Procedure: the tailing factor is not more than 2.0; and the relative standard deviation for replicate injections is not more than 5.0%.

Procedure— Separately inject equal volumes (about 200 µL) of the Working standard solution and the Test solution into the chromatograph, record the chromatograms, and measure the peak responses. Calculate the percentage of C19H30O3 dissolved by the formula: in which rU and rS are the peak responses for the Test solution and the Working standard solution, respectively; CS is the concentration, in mg per mL, of oxandrolone in the Working standard solution; 500 is the volume, in mL, of Medium; 100 is the conversion factor to percentage; and LC is the Tablet label claim, in mg.

Tolerances— Not less than 75% (Q) of the labeled amount of C19H30O3 is dissolved in 90 minutes.

100(CS / CU)(rU / rS)