(dye'' pir id' a mole).
» Dipyridamole contains not less than 98.0 percent and not more than 102.0 percent of C24H40N8O4, calculated on the dried basis.
Packaging and storage Preserve in tight, light-resistant containers. Store at room temperature.
USP Reference standards 11
Melting range 741: between 162 and 168, but the range between beginning and end of melting does not exceed 2.
Loss on drying 731 Dry it at 105 for 3 hours: it loses not more than 0.2% of its weight.
Chloride Dissolve 500 mg in 5 mL of alcohol and 2 mL of 2 N nitric acid, and add 1 mL of silver nitrate TS: no turbidity or precipitate is produced.
Residue on ignition 281: not more than 0.1%.
Heavy metals, Method II 231: 0.001%.
Mobile phase and Chromatographic system Prepare as directed in the Assay under Dipyridamole Tablets.
Test preparation A Prepare a solution of Dipyridamole in methanol having a known concentration of 1 mg per mL.
Test preparation B Dilute 1.0 mL of Test preparation A with methanol to 100 mL, and mix.
Procedure Inject 10 µL of Test preparation B into the chromatograph by means of a sampling valve, adjusting the operating parameters so that the response of the main peak (retention time about 6.5 minutes) obtained is about 5% full scale. Inject 10 µL of Test preparation A, and run the chromatograph for 10 minutes: the sum of responses of all secondary peaks obtained from Test preparation A is not greater than the response of the main peak obtained from Test preparation B (1.0%).
Assay Transfer about 450 mg of Dipyridamole, accurately weighed, to a 250-mL beaker, and dissolve in 50 mL of glacial acetic acid. Stir for 30 minutes. Add 75 mL of acetone, and stir for an additional 15 minutes. Titrate with 0.1 N perchloric acid VS, determining the endpoint potentiometrically, using a glass electrode and a silver-silver chloride reference electrode system. Perform a blank titration, and make any necessary correction. Each mL of 0.1 N perchloric acid is equivalent to 50.46 mg of C24H40N8O4.
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USP35NF30 Page 2938Pharmacopeial Forum: Volume No. 29(5) Page 1467