Dipyridamole Tablets

General Notices

Action and use

Adenosine reuptake inhibitor; inhibitor of platelet aggregation.

Definition

Dipyridamole Tablets contain Dipyridamole. They are coated.

The tablets comply with the requirements stated under Tablets and with the following requirements.

Content of dipyridamole, C₂₄H₄₀N₈O₄

95.0 to 105.0% of the stated amount.

Identification

Shake a quantity of the powdered tablets containing 50 mg of Dipyridamole with 20 mL of dichloromethane, filter and evaporate to dryness. The infrared absorption spectrum of the residue, Appendix II A, is concordant with the reference spectrum of dipyridamole (RS 108).

TESTS

Related substances

Carry out the method for liquid chromatography, Appendix III D, using the following solutions in amber glassware and protected from light.

(1) Shake a quantity of the powdered tablets containing 50 mg of Dipyridamole with 100 mL of methanol (60%) for 15 minutes, filter (Whatman GF/C filter is suitable) and use the filtrate.

(2) Dilute 1 mL of solution (1) to 200 mL with methanol (60%).

(3) Dissolve the contents of a vial of dipyridamole for peak identification EPCRS (dipyridamole and impurities A to F) in 1 mL of methanol (60%).

(4) Dilute 1 mL of solution (2) to 10 mL with methanol (60%).

chromatographic conditions

(a) Use a stainless steel column (10 cm × 4.0 mm) packed with end-capped octadecylsilyl silica gel for chromatography (5 µm) (Inertsil ODS2 is suitable).

(b) Use gradient elution and the mobile phase described below.

(d) Use a column temperature of 45°.

(e) Use a detection wavelength of 290 nm.

(f) Inject 5 µL of each solution.

mobile phase

Mobile phase ADissolve 1.0 g of potassium dihydrogen orthophosphate in 900 mL of water, adjust to pH 7.0 with 0.5m sodium hydroxide and dilute to 1000 mL with water.

Mobile phase Bmethanol.

system suitability

The test is not valid unless the chromatogram obtained with solution (3) closely resembles the chromatogram supplied with dipyridamole for peak identification EPCRS;

the resolution factor between impurity D and dipyridamole is at least 2.0.

limits

In the chromatogram obtained with solution (1):

identify any peak corresponding to impurity B and multiply the area of this peak by a correction factor of 1.7;

the area of any peak corresponding to impurity A, B, C, D or E is not greater than the area of the principal peak in the chromatogram obtained with solution (2) (0.5%);

the area of any other secondary peak not greater than 0.4 times the area of the principal peak in the chromatogram obtained with solution (2) (0.2%);

the sum of the areas of any such peaks is not greater than twice the area of the principal peak in the chromatogram obtained with solution (2) (1%).

Disregard any peak with an area less than the principal peak in the chromatogram obtained with solution (4) (0.05%).

Assay

Weigh and powder 20 tablets. Carry out the method for liquid chromatography, Appendix III D, using the following solutions in amber glassware and protected from light.

(1) Shake a quantity of the powdered tablets containing 50 mg of Dipyridamole with 100 mL of methanol (60%) for 15 minutes and filter (Whatman GF/C is suitable). Dilute 1 mL of the filtrate to 10 mL with methanol (60%).

(2) 0.005% w/v of dipyridamole BPCRS in methanol (60%).