VITAMIN E PHARMACOKINETICS: COMPARISON OF 1 VERSUS 8 HOUR INFUSION

Premature infants are vitamin E deficient at birth. Vitamin E administration by infusion is preferable to intramuscular injection because of the small muscle mass of very low blrthweight infants and the irritating nature of free tocopherol. Pharmacokinetics of intravenous vitamin E (IV) was evaluated in 9 preterm infants. 4 infants (Group 1, BW 990 ± 84 gms, GA = 29.2 ± 1.1 wks) were given a single dose of 10 mg/kg of dl-α tocopherol (Hoffmann LaRoche) by 1 hour infusion. The same dose was given to 5 infants (Group 2, BW 1138 ± 133.6 gms, GA = 28.4 ± 1.3 wks) by 8 hour infusion. Blood samples were obtained from central line immediately prior to (zero time) and at 2, 4, 6, 8, 10, 12, 15, 18, 24, 36, 48, 72 hours after vitamin E infusion. Pharmacokinetic parameters were obtained by model independent analysis of the serum vitamin E concentration time profile. Mean ± SD values for harmonic half life (T 1/2, hrs), volume of distribution (VD, liter/kg), serum clearance (SC ml/hr/kg) and selected serum vitamin E levels (E, mg/dl) for the two groups are: Infusion of vitamin E over 1 hour results in a significantly higher peak but similar steady state values as compared to 8 hours. These data can be used for dosing recommendation.