A: Powder finely a number of Tablets.To a portion of the powder,equivalent to about 1mg of levorphanol tartrate,add 1mLof water,1drop of 3Nhydrochloric acid,and 2drops of ferric chloride TS,and heat to boiling.To the hot solution add 1mLof potassium ferricyanide solution (1in 200):a bluish color develops.

B: Powder a number of Tablets,equivalent to about 60mg of levorphanol tartrate,and transfer the mixture to a small separator.Add 10mLof water,dissolve as much of the powder as possible,add about 400mg of sodium bicarbonate,and extract with a 50-mLportion of chloroform.Evaporate the filtered chloroform extract on a steam bath to a small volume,dilute with chloroform to 10mL,and determine the angular rotation:the solution is levorotatory (see Optical Rotation á781ñ).

Medium: water;500mL.

Apparatus 2: 50rpm.

Time: 30minutes.

Procedure— Determine the amount of C17H23NO·C4H6O6·2H2Odissolved from UVabsorbances at the wavelength of maximum absorbance at about 279nm on filtered portions of the solution under test,suitably diluted with water,in comparison with a Standard solution having a known concentration of USP Levorphanol Tartrate RSin the same medium.

Tolerances— Not less than 75%(Q)of the labeled amount of C17H23NO·C4H6O6·2H2Ois dissolved in 30minutes.

Procedure for content uniformity— Transfer 1Tablet to a glass-stoppered flask,add 25.0mLof 0.1Nhydrochloric acid,and allow the Tablet to disintegrate.Shake well,and filter through a small filter paper,discarding the first portion of the filtrate.Dilute a portion of the filtrate quantitatively and stepwise,if necessary,to provide a solution containing about 80µg of levorphanol tartrate per mL.Concomitantly determine the absorbances of this solution and of a solution of USP Levorphanol Tartrate RSin the same medium having a known concentration of about 80µg of anhydrous levorphanol tartrate per mL,in 1-cm cells at the wavelength of maximum absorbance at about 279nm,with a suitable spectrophotometer,using 0.1Nhydrochloric acid as the blank.Calculate the quantity,in mg,of C17H23NO·C4H6O6·2H2Oin the Tablet taken by the formula: in which 443.49and 407.47are the molecular weights of the hydrated and anhydrous forms of levorphanol tartrate,respectively;Tis the labeled quantity,in mg,of levorphanol tartrate in the Tablet;Cis the concentration,in µg per mL,of USP Levorphanol Tartrate RS,on the anhydrous basis,in the Standard solution;Dis the concentration,in µg per mL,of levorphanol tartrate in the solution from the Tablet,based on the labeled quantity per Tablet and the extent of dilution;and AUand ASare the absorbances of the solution from the Tablet and the Standard solution,respectively.