Biokinetics in Humans of RRR-alpha-tocopherol: The Free Phenol, Acetate Ester, and Succinate Ester Forms of Vitamin E

Free Radic Biol Med. 1995 Nov;19(5):591-8. doi: 10.1016/0891-5849(95)00083-a.

Abstract

The bioavailability of RRR-alpha-tocopherol from the oral administration of RRR-alpha-tocopherol itself and its acetate and succinate esters was determined in healthy human subjects. Venous blood samples were withdrawn periodically over a 51-h period following oral administration of a gelatin capsule containing an equimolar mixture of RRR-alpha-tocopherol and RRR-alpha-tocopheryl acetate. In a second study, subjects received a capsule containing an equimolar mixture of RRR-alpha-tocopheryl acetate and RRR-alpha-tocopheryl succinate. In Study 1, RRR-alpha-tocopherol was absorbed at similar rates from both the free phenol, and the acetate ester and maximum plasma levels occurred at 12 h in most subjects. The extent of absorption of RRR-alpha-tocopherol varied considerably between subjects in absolute terms, but the relative absorption from the two forms was remarkably consistent, and a ratio of 1.0 was found for parameters of relative bioavailability in plasma. The concentration of RRR-alpha-tocopherol from each form was maximal at approximately 27 h in red blood cells and, as seen with the plasma data, there was a large interindividual variability. In Study 2, there was no significant difference in the extent of absorption of RRR-alpha-tocopherol from the acetate ester and the succinate ester, although there was an apparently higher initial rate of absorption from the acetate ester.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Oral
  • Antioxidants / administration & dosage
  • Antioxidants / pharmacokinetics*
  • Biological Availability
  • Confidence Intervals
  • Gas Chromatography-Mass Spectrometry
  • Humans
  • Intestinal Absorption
  • Kinetics
  • Metabolic Clearance Rate
  • Reference Values
  • Stereoisomerism
  • Time Factors
  • Tocopherols
  • Vitamin E / administration & dosage
  • Vitamin E / analogs & derivatives
  • Vitamin E / blood
  • Vitamin E / pharmacokinetics*
  • alpha-Tocopherol* / analogs & derivatives*

Substances

  • Antioxidants
  • Vitamin E
  • alpha-Tocopherol
  • Tocopherols