Dyphylline
;)
1H-Purine-2,6-dione,7-(2,3-dihydroxypropyl)-3,7-dihydro-1,3-dimethyl-,(±)-.
(±)-7-(2,3-Dihydroxypropyl)theophylline [479-18-5].
»Dyphylline contains not less than 98.0percent and not more than 102.0percent of C10H14N4O4,calculated on the dried basis.
Packaging and storage—
Preserve in tight containers.
Identification—
A:
Infrared Absorption á197Kñ.
Solution:
10µg per mL.
Medium:
water.
pHá791ñ:
between 5.0and 7.5,in a solution (1in 100).
Loss on drying á731ñ—
Dry about 1g,accurately weighed,at 105
for 3hours:it loses not more than 0.5%of its weight.
for 3hours:it loses not more than 0.5%of its weight.
Residue on ignition á281ñ:
not more than 0.15%.
Chloride á221ñ:
A1.0-g portion shows no more chloride than corresponds to 0.50mLof 0.020Nhydrochloric acid (0.035%).
Sulfate á221ñ:
A1.0-g portion shows no more sulfate than corresponds to 0.10mLof 0.020Nsulfuric acid (0.010%).
Heavy metals,Method Iá231ñ:
0.002%.
Limit of theophylline—
Dissolve 2.0g in 10mLof hot water.Cool,add 10drops of bromothymol blue TSand 5.0mLof silver nitrate TS,and mix.Not more than 0.50mLof 0.10Nsodium hydroxide is required to change the color of the solution to blue (0.5%).
Related compounds—
Dissolve about 200mg in a mixture of 30volumes of methanol and 20volumes of water in a 10-mLvolumetric flask,dilute with the same mixture to volume,and mix (Test solution).Dilute 1mLof the Test solutionwith methanol to 100mL(Diluted test solution).Separately apply 10µLof each solution to a suitable thin-layer chromatographic plate (see Chromatography á621ñ)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 15cm.Remove the plate,air-dry at room temperature,and examine under short-wavelength UVlight:no spot in the chromatogram of the Test solutionother than the principal spot is larger or more intense than the principal spot from the Diluted test solution(1.0%).
Organic volatile impurities,Method Iá467ñ:
meets the requirements.
Assay—
Dissolve about 200mg of Dyphylline,accurately weighed,in 2mLof formic acid,and carefully add,with stirring,50mLof acetic anhydride.Add 0.2mLof Sudan IV TS,and titrate with 0.1Nperchloric acid VSto a deep violet endpoint.Perform a blank determination,and make any necessary correction.Each mLof 0.1Nperchloric acid is equivalent to 25.42mg of C10H14N4O4.
Auxiliary Information—
Staff Liaison:Karen A Russo,Ph.D.,Scientist
Expert Committee:(PA1)Pharmaceutical Analysis 1
USP28–NF23Page 708
Pharmacopeial Forum:Volume No.29(5)Page 1473
Phone Number:1-301-816-8379