A: Transfer a quantity of Oral Solution, equivalent to about 1.25 mg of hyoscyamine sulfate, to a separator. Render alkaline with 6 N ammonium hydroxide, and extract with 10 mL of methylene chloride, filtering the extract into a beaker. Evaporate to dryness. Add 2 drops of nitric acid to the dry residue, and evaporate on a steam bath to dryness. Add a few drops of alcoholic potassium hydroxide TS: a violet color is produced.

B: Transfer a quantity of Oral Solution, equivalent to about 2.5 mg of hyoscyamine sulfate, to a separator. Render the solution acidic with 3 N sulfuric acid, and extract with methylene chloride. Discard the extract. Render the solution alkaline with 6 N ammonium hydroxide, and extract with methylene chloride, filtering the extract into a beaker. Evaporate to dryness. Dissolve the residue in a small amount of 0.1 N hydrochloric acid, and add gold chloride TS, with shaking, until a definite precipitate separates. Slowly heat until the precipitate dissolves, and allow the solution to cool: lustrous golden yellow scales are formed.

FOR ORAL SOLUTION PACKAGED IN SINGLE-UNIT CONTAINERS: meets the requirements.

FOR ORAL SOLUTION PACKAGED IN MULTIPLE-UNIT CONTAINERS: meets the requirements.

(Official January 1, 2007)

Diluent, Mobile phase, Standard preparation, and Chromatographic system— Proceed as directed in the Assay under Hyoscyamine Sulfate Injection.

Assay preparation— Transfer an accurately measured volume of Oral Solution, equivalent to about 0.5 mg of hyoscyamine sulfate, to a 100-mL volumetric flask, dilute with Diluent to volume, and mix. Pass an aliquot through a 0.45-µm filter, discarding the first 5 mL of the filtrate.

Procedure— Separately inject equal volumes (about 50 µL) of the Standard preparation and the Assay preparation into the chromatograph, record the chromatograms, and measure the area responses for the major peaks. Calculate the quantity, in mg, of hyoscyamine sulfate [(C17H23NO3)2·H2SO4·2H2O] in each mL of the Oral Solution taken by the formula: in which 1.053 is the ratio of the molecular weight of hydrated hyoscyamine sulfate to that of anhydrous hyoscyamine sulfate; C is defined under Standard preparation; V is the volume, in mL, of Oral Solution taken; and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.