A: Thin-Layer Chromatographic Identification Test 201—

B: The retention times of the peaks for silydianin, silychristin, silybin A, silybin B, isosilybin A, and isosilybin B in the chromatogram of the Test solution correspond to those in the chromatogram of Milk thistle standard solution, as obtained in the test for Content of silymarin.

Solution A, Solution B, Mobile phase, Silybin standard solutions, and Chromatographic system— Proceed as directed in the test for Content of silymarin under Milk Thistle.

Milk thistle standard solution— Prepare as directed for Milk thistle standard solution in the test for Content of silymarin under Powdered Milk Thistle Extract.

Test solution— Weigh and finely powder not fewer than 20 Tablets. Transfer an accurately weighed quantity of the powder, equivalent to about 100 mg of silymarin, to a 100-mL volumetric flask, add 90 mL of methanol, and sonicate for 20 minutes with occasional shaking. Cool to 20, and dilute with methanol to volume. Filter through a membrane having a 0.45-µm or finer porosity.

Procedure— Proceed as directed in the test for Content of silymarin under Milk Thistle, except to separately calculate the amount, in mg, of each relevant component of silymarin as silybin (C25H22O10) in the portion of Tablets taken by the formula: in which the term, C, is as defined therein. Calculate the amount of silymarin, in mg, in the portion of Tablets taken by adding the individual amounts obtained.