Procedure
Proceed as directed for
Procedure under
Single-Steroid Assay 511, using a solvent system consisting of chloroform, methanol, and water (180:15:1), through the fourth sentence of the second paragraph under
Procedure. Then centrifuge the tubes for 5 minutes, and determine the absorbances of the supernatants in 1-cm cells at the wavelength of maximum absorbance at about 238 nm, with a suitable spectrophotometer, against the blank. Calculate the quantity, in mg, of C
22H
28O
5 in the portion of Meprednisone taken by the formula:
10C(AU / AS),
in which
C is the concentration, in mg per mL, of
USP Meprednisone RS in the
Standard preparation; and
AU and
AS are the absorbances of the solutions from the
Assay preparation and the
Standard preparation, respectively.