(dye' fi lin).
1H-Purine-2,6-dione, 7-(2,3-dihydroxypropyl)-3,7-dihydro-1,3-dimethyl-, (±)-.
» Dyphylline contains not less than 98.0 percent and not more than 102.0 percent of C10H14N4O4, calculated on the dried basis.
Packaging and storage Preserve in tight containers.
USP Reference standards 11
Solution: 10 µg per mL.
Melting range 741: between 160 and 164.
pH 791: between 5.0 and 7.5, in a solution (1 in 100).
Loss on drying 731 Dry about 1 g, accurately weighed, at 105 for 3 hours: it loses not more than 0.5% of its weight.
Residue on ignition 281: not more than 0.15%.
Chloride 221: A 1.0-g portion shows no more chloride than corresponds to 0.50 mL of 0.020 N hydrochloric acid (0.035%).
Sulfate 221: A 1.0-g portion shows no more sulfate than corresponds to 0.10 mL of 0.020 N sulfuric acid (0.010%).
Heavy metals, Method I 231: 0.002%.
Limit of theophylline Dissolve 2.0 g in 10 mL of hot water. Cool, add 10 drops of bromothymol blue TS and 5.0 mL of silver nitrate TS, and mix. Not more than 0.50 mL of 0.10 N sodium hydroxide is required to change the color of the solution to blue (0.5%).
Related compounds Dissolve about 200 mg in a mixture of 30 volumes of methanol and 20 volumes of water in a 10-mL volumetric flask, dilute with the same mixture to volume, and mix (Test solution). Dilute 1 mL of the Test solution with methanol to 100 mL (Diluted test solution). Separately apply 10 µL of each solution to a suitable thin-layer chromatographic plate (see Chromatography 621) coated with a 0.25-mm layer of binder-free chromatographic silica gel mixture. Develop the plate in a suitable chamber containing a mixture of chloroform, dehydrated alcohol, and ammonium hydroxide (90:10:1) until the solvent front has moved about 15 cm. Remove the plate, air-dry at room temperature, and examine under short-wavelength UV light: no spot in the chromatogram of the Test solution other than the principal spot is larger or more intense than the principal spot from the Diluted test solution (1.0%).
Assay Dissolve about 200 mg of Dyphylline, accurately weighed, in 2 mL of formic acid, and carefully add, with stirring, 50 mL of acetic anhydride. Add 0.2 mL of Sudan IV TS, and titrate with 0.1 N perchloric acid VS to a deep violet endpoint. Perform a blank determination, and make any necessary correction. Each mL of 0.1 N perchloric acid is equivalent to 25.42 mg of C10H14N4O4.
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USP35NF30 Page 2999Pharmacopeial Forum: Volume No. 29(5) Page 1473