Techniques were developed for kinetic studies in unanesthetized, unrestrained minipigs weighing less than 45.4 kg (100 Ib). By using 3%-heparin and 3H-heparin, the disappearance from the plasma of different amounts of heparin injected intravenously into the minipig was determined. Serial plasma samples were assayed for radioactivity, and the resulting plasma radioactivity-time curves were analyzed .for calculation of half-lives of disappearance ( t l , z ) and volume of distribution (Vd). The plasma radioactivity followed a monoexponential decay. Over the 1-50mg heparin range, an increase in t l 1 2 from 3.4 to 39 min was observed. Essentially no differences in the V, were observed among the various doses. This volume was approximately 1.5 times the estimated plasma volume. The observed kinetics are consistent with previous suggestions that the reticuloendothelial system may be involved in the disposition of heparin.
Keyphrases 0 Heparin-kinetics of removal from circulation of minipig Minipig-kinetics of heparin removal from circulation, suitability as test animal 0 Anticoagulants-kinetics of heparin removal from circulation of minipig 0 Pharmacokinetics-heparin removal from circulation of minipig