Pharmacokinetics of orally administered DL-α-lipoic acid in dogs.

OBJECTIVE To determine the pharmacokinetics of DL-α-lipoic acid in dogs when administered at 3 dosages via 3 methods of delivery. ANIMALS 27 clinically normal Beagles. PROCEDURES In a 3 × 3 factorial Latin square design, 3 dosages (2.5, 12.5, and 25 mg/kg) of DL-α-lipoic acid were administered orally in a capsule form and provided without a meal, in a capsule form and provided with a meal, and as an ingredient included in an extruded dog food. Food was withheld for 12 hours prior to DL-α-lipoic acid administration. Blood samples were collected before (0 minutes) and at 15, 30, 45, 60, and 120 minutes after administration. Plasma concentrations of DL-α-lipoic acid were determined via high-performance liquid chromatography. A generalized linear models procedure was used to evaluate the effects of method of delivery and dosage. Noncompartmental analysis was used to determine pharmacokinetic parameters of DL-α-lipoic acid. Nonparametric tests were used to detect significant differences between pharmacokinetic parameters among treatment groups. RESULTS A significant effect of dosage was observed regardless of delivery method. Method of delivery also significantly affected plasma concentrations of DL-α-lipoic acid, with extruded foods resulting in lowest concentration for each dosage administered. Maximum plasma concentration was significantly affected by method of delivery at each dosage administered. Other significant changes in pharmacokinetic parameters were variable and dependent on dosage and method of delivery. CONCLUSIONS AND CLINICAL RELEVANCE Values for pharmacokinetic parameters of orally administered DL-α-lipoic acid may differ significantly when there are changes in dosage, method of administration, and fed status.