Plasma kinetics of tritiated d-alpha-tocopherol in sheep given intravenously in emulsion or ethanol.

Thirteen crossbred wethers were given intravenously tritiated d-alpha-tocopherol (2 microCi/kg of bw) dissolved in emulsion or ethanol. Kinetic evaluation of the plasma specific activity versus time data was performed using either the 2- or 3-compartment model. The disappearance of the radiolabelled alpha-tocopherol from the plasma pool was affected by the nature of the vehicle administered. Radiotocopherol was cleared from plasma much faster when it was dissolved in ethanol than in emulsion; when radiotocopherol was injected as an emulsion concentration time curves were best described as a 2-compartment open model and in ethanol the kinetic data fitted a sum of three exponentials. The data showed higher bioavailability of the intravenously injected vitamin E in emulsion over ethanol.