Plasma alpha-tocopherol profiles in sheep after oral administration of dl-alpha-tocopheryl acetate and d-alpha-tocopheryl succinate.

The purpose of this study was to compare the bioavailability of dl-alpha-tocopheryl acetate and d-alpha-tocopheryl succinate when administered to sheep in a single oral dose weekly. The sheep, five per treatment, were given a basal diet without vitamin E supplement (control) or basal diet with weekly administration of 2225 IU of dl-alpha-tocopheryl acetate, 2225 IU of d-alpha-tocopheryl succinate, or 6675 IU of d-alpha-tocopheryl succinate. Increases in plasma alpha-tocopherol concentration levels over the 3-wk period of study were determined and compared. The greater availability of dl-alpha-tocopheryl acetate was indicated by the significantly higher peak plasma alpha-tocopherol concentrations and the greater area under the curve produced by administration of the acetate than the succinate esters at the same dosage. Reported data on plasma alpha-tocopherol concentrations suggest that bioavailability in sheep of d-alpha-tocopheryl succinate versus dl-alpha-tocopheryl acetate is 3:1.