Dissolution 
711
—
Medium:
water; 900 mL.
Apparatus 2:
50 rpm.
Time:
45 minutes.
Procedure—
Determine the amount of C
17H
20N
4O
6 dissolved, employing the procedure set forth in the
Assay for niacin or niacinamide, pyridoxine hydrochloride, riboflavin, and thiamine under
Water-soluble Vitamins Tablets using filtered portions of the solution under test, suitably diluted with
Dissolution Medium if necessary, in comparison with a Standard solution having a known concentration of
USP Riboflavin RS in the same medium.
Tolerances—
Not less than 75% (Q) of the labeled amount of C17H20N4O6 is dissolved in 45 minutes.
Assay—
Weigh and finely powder not fewer than 20 Tablets. Weigh accurately a portion of the powder, equivalent to about 20 mg of riboflavin, transfer to a 250-mL flask, and add 150 mL of 0.1 N hydrochloric acid. Shake vigorously, and wash down the sides of the flask with sufficient 0.1 N hydrochloric acid to ensure that the pH remains below 1.5 during the subsequent period of heating. Heat the mixture on a steam bath, with frequent agitation, until the riboflavin has dissolved, or in an autoclave at 121
for 30 minutes. Cool, adjust the mixture, with vigorous agitation, to a pH of 5 to 6 with 1 N sodium hydroxide, transfer to a 1000-mL volumetric flask, dilute with water to volume, and mix. If the solution is not clear, filter through paper known not to adsorb riboflavin. Dilute an aliquot of the clear solution quantitatively and stepwise with water to make a final measured volume that contains approximately 0.1 µg of riboflavin per mL. Using this as the
Assay Preparation, proceed as directed under
Riboflavin Assay 481. Calculate the quantity, in mg, of C
17H
20N
4O
6 in the portion of powdered Tablets taken by the formula:
200,000C / W,
in which
C is the concentration, in mg per mL, of C
17H
20N
4O
6 obtained for the
Assay Preparation, and
W is the weight, in mg, of powdered Tablets. Calculate the quantity, in mg, of C
17H
20N
4O
6 in each Tablet.
