Plasma kinetics of parenteral tocopherol in premature infants.
The potential use of alpha-tocopherol (alpha-T) in the prevention of retrolental fibroplasia led to a study of the plasma kinetics of alpha-T. A dose of 20 mg alpha-tocopherol acetate (alpha-T-Ac) was injected subcutaneously in 5 premature newborns. alpha-T-Ac and alpha-T were assayed by high-pressure liquid chromatography. The maximum plasma concentration of alpha-T-Ac was 2.0 +/- 0.60 mg/dl (mean +/- SEM). alpha-T concentrations remained above 0.5 mg/dl from 8 to 168 h with a mean peak plasma concentration of 2.15 +/- 0.45 mg/dl. alpha-T-Ac absorption and elimination half-lives were 7.0 +/- 0.7 and 23.2 +/- 9.0 h, respectively; alpha-T appearance and elimination half-lives were 12.8 +/- 3.1 and 80.6 +/- 21.0 h. The proposed dosage to keep a plasma level higher than 0.5 mg/dl is 20 mg of alpha-T-Ac every 5 days.
D000042:Absorption; D006207:Half-Life; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000097:blood / Q000378:metabolism*; D007279:Injections, Subcutaneous; D007700:Kinetics; D024505:Tocopherols; D014810:Vitamin E / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000097:blood / Q000378:metabolism*; D024502:alpha-Tocopherol / Q000031:analogs & derivatives*
D014810:Vitamin E; D024502:alpha-Tocopherol; D024505:Tocopherols