COMPARISON OF ALPHA-TOCOPHEROL ACETATE PREPARATIONS GIVEN AS SINGLE INTRAPERITONEAL OR SUBCUTANEOUS DOSES FOR INCREASING PLASMA AND LIVER ALPHA-TOCOPHEROL IN SHEEP FED A LOW VITAMIN-E DIET

This experiment examined the efficacy of a single dose of a-tocopherol acetate (2000 TU) in either an aqueous or oily formulation, given as an intraperitoneal (i.p.) or subcutaneous (s.c.) injection or orally a s an aqueous formulation, at raising a-tocopherol concentrations in bl ood plasma and liver of young sheep with low vitamin E. Maximum plasma concentrations (C-max) were greatest in sheep supplemented by the s.c .-aqueous method or orally (4.83 and 3.49 mg/L respectively). These va lues were 3.0-5.7 times the C-max values of the other treatment max (T -max) was far shorter in these 2 treatments than in the other treatmen ts (T-max values were 0.70 and 0.65 days respectively). T-max values w ere greatest for the oily formulation (42 and 73 days for the i.p. and s.c. injections, respectively). The area under the plasma a-tocophero l concentration-time curve (AUC((0-85d))), was greatest for the s.c.-a queous group (median of 2066 mg.h/L). Six of the sheep in the i.p.-aqu eous values similar to the controls group had AUC((0-85d)) whereas the rest were similar to the s.c.-aqueous group. Plasma alpha-tocopherol acetate was only consistently detected in sheep in the s.c.-aqueous gr oup (C-max of 25.25 +/- 3.14 mg/L and T-max of 0.24 +/- 0.03 days). Ph armacokinetic modelling of the plasma data obtained from sheep in the s.c.-aqueous group was helpful in understanding the factors which cont rolled the appearance and disappearance rates of plasma a-tocopherol i n this group. In contrast to plasma data, liver concentrations of alph a-tocopherol at days 24 and 57 were greatest in sheep supplemented by the i.p.-oily method. The s.c.-aqueous was the second most effective m ethod at raising concentrations in the liver. The results suggest that supplementation by s.c. injection of an aqueous formulation may be an effective means of administering vitamin E to sheep.