Medium: water; 900 mL.

Apparatus 2 : 50 rpm.

Time: 30 minutes.

Procedure— Measure the UV absorption of filtered aliquots removed from the Dissolution Medium and suitably diluted, if necessary, in 1-cm cells at 246 nm, with a suitable spectrophotometer, using water as the blank and utilizing a standard curve, representing the absorbance versus concentration of USP Methylprednisolone RS. [NOTE—Dissolve about 20 mg of USP Methylprednisolone RS, accurately weighed, in 1 mL of alcohol, dilute in a 1000-mL volumetric flask with water to volume, and mix. Prepare quantitative dilutions of this solution for the development of a standard curve.]

Tolerances— Not less than 70% (Q) of the labeled amount of C22H30O5 is dissolved in 30 minutes.

PROCEDURE FOR CONTENT UNIFORMITY—

Mobile phase, Internal standard solution, Standard preparation, and Chromatographic system— Proceed as directed in the Assay under Methylprednisolone.

Test preparation— Place 1 Tablet in a suitable container. For tablet labeled strengths of 10 mg or less, add 0.5 mL of water. For tablet labeled strengths greater than 10 mg, add 1.0 mL of water. Allow the tablet to stand for about 2 minutes, then swirl the container to disperse the tablet. Add 5.0 mL of Internal standard solution for each mg of labeled tablet strength, shake for 15 minutes, and filter or centrifuge a portion of the test specimen. Analyze the clear solution as directed under Procedure.

Procedure— Proceed as directed for Procedure in the Assay under Methylprednisolone. Calculate the quantity, in mg, of C22H30O5 in the Tablet taken by the formula: in which F is the ratio of the volume of Internal standard preparation, in mL, in the Test preparation to the volume, in mL, of the Internal standard preparation in the Standard preparation; WS is the weight, in mg, of USP Methylprednisolone RS taken for the Standard preparation; and the other terms are as defined for Procedure in the Assay under Methylprednisolone.

(Official January 1, 2007)

Mobile phase, Internal standard solution, Standard preparation, and Chromatographic system— Proceed as directed in the Assay under Methylprednisolone.

Assay preparation— Accurately weigh 20 Tablets, and grind to a fine powder in a mortar and pestle. Accurately weigh a portion of the powder, equivalent to about 10 mg of methylprednisolone, and transfer to a suitable container. Add 2.5 mL of water to the ground tablet material and swirl to form a fine slurry. Add 50.0 mL of Internal standard solution, and shake for 15 minutes. Filter or centrifuge a portion of the liquid so obtained, if necessary, and analyze the clear solution as directed under Procedure.

Procedure— Proceed as directed for Procedure in the Assay under Methylprednisolone. Calculate the quantity, in mg, of C22H30O5 in the portion of Tablets taken by the formula: in which the terms are as defined therein.