Pharmacokinetics of dipyridamole-beta-cyclodextrin complex in dogs.

Plasma concentrations and urinary and fecal excretion of intact dipyridamole were followed in dogs after oral administration of dipyridamole-beta-cyclodextrin complex (dip-beta-CD) (capsules containing 37.5 and 75 mg of active principle), of commercial dipyridamole and of dipyridamole. HCl (tablets and capsules of 75 mg of active principle, respectively), according to a crossover design. Dip-beta-CD afforded significantly shorter lag-times, higher Cmax, smaller interindividual variations of plasma concentrations and greater urinary excretion than the other two preparations, as a consequence of a better bioavailability of the former one. This amelioration seems to be due not only to an increased wettability and water solubility of the product, but also to a finer molecular dispersion in the gastrointestinal fluids which favors the contact of dipyridamole with a greater absorption surface.