Procedure
Transfer 20.0 mL each of the
Standard preparation and the
Assay preparation to separate 50-mL volumetric flasks. To each flask add, with mixing, 1.0 mL of hydrochloric acid and 1.0 mL of sodium nitrite solution (1 in 20). Insert the stoppers, allow to stand for 40 to 45 minutes, with occasional swirling, then add 2 mL of ammonium hydroxide, and mix. Allow to stand for 2 minutes, then dilute with water to volume, and mix. Concomitantly determine the absorbances of the solutions in 1-cm cells at the wavelength of maximum absorbance at about 440 nm, with a suitable spectrophotometer, using water as the blank. Calculate the quantity, in mg, of hydromorphone hydrochloride (C
17H
19NO
3·HCl) in each mL of the Injection taken by the formula:
(VA / VI)(C)(AU / AS),
in which
VA is the volume, in mL, of the
Assay preparation;
VI is the volume, in mL, of Injection taken to prepare the
Assay preparation;
C is the concentration, in mg per mL, of
USP Hydromorphone Hydrochloride RS in the
Standard preparation; and
AU and
AS are the absorbances of the solutions from the
Assay preparation and the
Standard preparation, respectively.