Abstract
Pharmacokinetics of S-1108 were investigated in the elderly. The serum Concentrations of S-1006 were determined after oral administration of 100mg and 150mg of S-1108 to ten aged subjects (mean age=76.5±7.4 years). In the 100mg dose group, the maximal serum concentration was attained 2 to 6 hours after administration, and the mean value ranged from 0.56 to 2.16μg/ml (mean=1.12±0.61μg/ml). In the 150 mg dose group, the maximal serum concentration was attained 2 to 6 hours after administration, and the mean value ranged from 0.56 to 2.23μg/ml (mean=1.47±0.65μg/ml). Urinary recovery of S-1108 within 24 hours in the 100mg dose group and in the 150mg dose group was 22.2% and 25.4%, respectively. Thus, the maximal serum concentration of S-1006 in the elderly was nearly equal to that in the adult. However, the half life of S-1006 in the elderly was slightly longer than in the adult. This indicates that the administration intervals of the drug should be longer in the elderly than those in the young.
With regard to carnitine (CRN) metabolism, urinary recovery of CRN within 4 hours in the 100mg dose group and in the 150mg dose group was 35.7μ mol and 226 μ mol, respectively. Serum concentration of CRN 4 hours after administration of 100mg S-1108 and 150mg S-1108 were 63.9±1.9 nmol/ml and 60.4±24.6 nmol/ml, respectively. Additionally, the ratio of acyl CRN to free CRN in serum in the 100mg dose group and the150mg dose group was 0.38 and 0.27, respectively. It therefore appears that CRN body stores are little influenced by S-1108 administration even in the elderly. Moreover, no adverse reactions were observed in any ot the subjects.
