Oxtriphylline Oral Solution
» Oxtriphylline Oral Solution contains an amount of oxtriphylline equivalent to not less than 90.0 percent and not more than 110.0 percent of the labeled amount of anhydrous theophylline (C7H8N4O2).
Packaging and storage— Preserve in tight containers.
Labeling— Label Oral Solution to state both the content of oxtriphylline and the content of anhydrous theophylline.
USP Reference standards 11
USP Oxtriphylline RS Click to View Structure
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.
pH 791: between 6.4 and 9.0.
Alcohol content (if present), Method I 611: between 90.0% and 115.0% of the labeled amount, the labeled amount being not more than 20.0% of C2H5OH.
Assay—
Mobile phase, Standard preparation, System suitability preparation, and Chromatographic system— Prepare as directed in the Assay under Oxtriphylline Delayed-release Tablets.
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 C7H8N4O2 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.
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USP35–NF30 Page 4161