Pharmacokinetics

Absorption

The branched-chain amino acids administered to rats were rapidly absorbed, reaching a peak concentration in plasma and in whole blood 4 hours after dosing, followed by a slow decline. It was also demonstrated that the absorption was not significantly affected by repetitive dosing. In liver disorder model rats, absorption of the branched-chain amino acids administered proceeded slower than that in normal rats.

Distribution

The branched-chain amino acids administered and transferred to plasma were promptly utilized for plasma protein synthesis. The branched-chain amino acids absorbed were distributed extensively to the whole body, conspicuously to tissues with active protein synthesis. It was also demonstrated that their distribution was not significantly affected by repetitive dosing.

In liver disorder model rats, their transition to plasma protein and distribution were essentially comparable with those seen in normal rats.

Metabolism

No information

Excretion

During a 168-hour period after dosing, the branched-chain amino acids administered was excreted in urine and feces, and in expired air, 4% and 41%, respectively. It indicated that the branched-chain amino acids administered were utilized in part as a source of energy. It was also demonstrated that their excretion was not significantly affected by repetitive dosing.

In liver disorder model rats, their excretion in urine and feces were essentially comparable with those seen in normal rats. It was thus indicated that the branched-chain amino acids administered were effectively utilized as substrates for protein synthesis in liver disorder model rats as well. Compared with normal rats, the excretion in expired air was greater in liver disorder model rats, in which the branched-chain amino acids administered were thus more efficiently utilized as a source of energy.