Pharmacokinetics and tissue uptake of D-alpha-tocopherol in sheep following a single intraperitoneal injection.

D-alpha-Tocopherol in an emulsible base was administered i.p. to four groups of five sheep each at doses of 0, 1250, 2500, and 5000 IU. Blood was sampled regularly until slaughter at 7 d after administration. Plasma and tissue concentrations of D-alpha-tocopherol were measured by HPLC. Pharmacokinetic analysis of plasma concentrations, for the three tested doses, showed an absence of significant difference for lag time to absorption (.9 to 2.5 h), half-time of absorption (15 to 30 h), plasma half-life (31 to 42 h), and time of maximal concentration (18 to 31 h). In contrast, dose had a significant effect on area under the tocopherol plasma curve and on the maximal concentration. For both parameters, statistical evidence indicated nonlinearity for disposition of D-alpha-tocopherol, but without biological significance; by 7 d after dosing, amounts of residue of tocopherol were highest in the pancreas and adrenal glands (approximately 65 and 47 micrograms/g, respectively, for the 5000 IU dose) and lowest in neck muscle (approximately 4 micrograms/g for the 5000 IU dose). Kidney had an intermediate level of tocopherol. The intraperitoneal route is an efficient route for tocopherol administration in sheep.