Assay for cascarosides—
[N
OTE 1—Perform all extractions by shaking vigorously, and allow all phases to separate completely before transferring. Entrainment of aglycones into the aqueous phase, as indicated by a value of less than 2.7 for the ratio of the absorbance of the final solution at 515 nm to that at 440 nm, may lead to false results. N
OTE 2—Throughout this assay, use 1 N sodium hydroxide that is prepared without added barium ions as directed for
Volumetric Solutions under
Reagents,
Indicators,
and Solutions.]
Ferric chloride solution—
Dissolve 100 g of ferric chloride in water to make 100 mL.
Assay solution—
Weigh and finely powder not less than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 1.0 g of Cascara Sagrada Extract, to a 100-mL volumetric flask. Add about 60 mL of 70% alcohol, swirl and/or sonicate for 15 to 20 minutes, several times, allow to stand overnight, sonicate or swirl for 10 to 15 minutes, dilute with 70% alcohol to volume, mix, and filter through suitable filter paper.
Assay preparation—
Prepare as directed in the Assay for cascarosides under Cascara Sagrada.
Procedure—
Pipet 20 mL of
Assay preparation into a flask containing 2 mL of
Ferric chloride solution and 12 mL of hydrochloric acid. Proceed as directed for
Procedure in the
Assay for cascarosides under
Cascara Sagrada, beginning with “Attach a condenser arranged for refluxing, and heat for 3 hours,” except to evaporate a 15.0-mL portion of the methylene chloride solution instead of 20.0 mL. Calculate the quantity, in mg, of cascarosides in the portion of Tablets taken by the formula:
103.5AU,
in which
AU is the absorbance of the solution from the
Assay preparation.
Assay for total hydroxyanthracene derivatives—
[N
OTE 1—Perform all extractions by shaking vigorously, and allow all phases to separate completely before transferring. Entrainment of aglycones into the aqueous phase, as indicated by a value of less than 2.6 for the ratio of the absorbance of the final solution at 515 nm to that at 440 nm, may lead to false results. N
OTE 2—Throughout this assay, use 1 N sodium hydroxide that is prepared without added barium ions as directed for
Volumetric Solutions in the section
Reagents,
Indicators,
and Solutions.]
Procedure—
Pipet 10 mL of
Assay preparation into a flask containing 2 mL of
Ferric chloride solution and 12 mL of hydrochloric acid. Proceed as directed for
Procedure in the
Assay for cascarosides under
Cascara Sagrada, beginning with “Attach a condenser arranged for refluxing, and heat for 3 hours,” except to evaporate a 15.0-mL portion of the methylene chloride solution instead of 20.0 mL. Calculate the quantity, in mg, of total hydroxyanthracene derivatives in the portion of Tablets taken by the formula:
206.9AU,
in which
AU is the absorbance of the solution from the
Assay preparation.
701
:
60 minutes.