(dye'' pir id' a mole).
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C24H40N8O4 504.63

Ethanol, 2,2¢,2¢¢,2¢¢¢-[4,8-di-1-piperidinylpyrimido[5,4-d]pyrimidine-2,6-diyl)dinitrilo]tetrakis-.
2,2¢,2¢¢,2¢¢¢-[4,8-Dipiperidinopyrimido[5,4-d]pyrimidine-2,6-diyl)dinitrilo]tetraethanol [58-32-2].
» 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
USP Dipyridamole RS Click to View Structure
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%.
Chromatographic purity—
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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Monograph Sujatha Ramakrishna, Ph.D.
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(SM22010) Monographs - Small Molecules 2
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