Packaging and storage
Preserve in tight containers.
Labeling
Label Oral Solution to state both the content of oxtriphylline and the content of anhydrous theophylline.
Identification
A:
The retention time exhibited by theophylline in the chromatogram of the
Assay preparation corresponds to that of theophylline in the chromatogram of the
Standard preparation, as obtained in the
Assay.
B:
Place a volume of Oral Solution, equivalent to about 100 mg of oxtriphylline, in a 60-mL separator containing 1 mL of glacial acetic acid and 40 mL of chloroform. Shake for 1 minute, allow the phases to separate, and filter the lower phase through dry cotton into a 100-mL beaker. Transfer a portion of the chloroform solution, equivalent to about 10 mg of oxtriphylline, to a porcelain dish, and evaporate on a steam bath with the aid of a current of dry air to dryness. Add 1 mL of hydrochloric acid and 100 mg of potassium chlorate, evaporate on a steam bath to dryness, and invert the dish over a vessel containing a few drops of 6 N ammonium hydroxide: the residue acquires a purple color.
Assay
Assay preparation
Transfer an accurately measured volume of Oral Solution, equivalent to about 100 mg of oxtriphylline, to a 1000-mL volumetric flask, dilute with water to volume, and mix.
Procedure
Proceed as directed for
Procedure in the
Assay under
Oxtriphylline Delayed-release Tablets. Calculate the quantity, in mg, of C
7H
8N
4O
2 in each mL of the Oral Solution taken by the formula:
(180.17 / 283.33)(C / V)(rU / rS),
in which
V is the volume, in mL, of Oral Solution taken to prepare the
Assay preparation, and the other terms are as defined therein.