[Biological availability of Ossin, a sodium-fluoride dragee for osteoporosis therapy].

The bioavailability of Ossin, a drug for the treatment of osteoporosis, containing 40 mg of NaF, was investigated. Because of the enteric coating of the tablet, intestinal absorption occurs when the tablet leaves the stomach. The sustained release of the F--in the intestine results in a slow F-- -absorption. Maximal F-- -serum concentrations are reached more than 4 hours after absorption has begun. In contrast to non-sustained release NaF tablets the slow absorption of Ossin leads to lower, and less variable F-- -serum concentrations. Following administration of 1 tablet Ossii b.i.d., the steady state concentrations were between 130 and 220 ng/ml. The absorption was at least 86%. As calculated by the renal F-- -elimination, the therapeutically important F-- -retention in bone amounted to more than 50%. The enteric coating of the Ossin tablets, the low and relatively steady F-- -serum concentrations and the high F-- -retention in bone, are expected to contribute to an improvement in tolerance and therapeutic efficacy in the treatment of osteoporosis.