Plasma and urine pharmacokinetics of free and of short-chain carnitine after administration of carnitine in man.
To 6 healthy volunteers 30 mg/kg of L-carnitine (1,3-hydroxy-4-N-trimethylamino-butyrate) were injected intravenously and plasma levels (mumol/l) of free and short-chain carnitine were determined at different times between 0.033 and 24 h. The urinary excretion of L-carnitine and short-chain carnitine in 24 h was also measured. After a period of wash-out the subjects received 100 mg/kg of L-carnitine orally and plasma levels were determined between 0.5 and 24 h. The urinary excretion of L-carnitine was measured for a period of 18.5-33 h after treatment. 3 of the volunteers also received 30 mg/kg of L-carnitine orally. Carnitine plasma levels were determined at different times between 0.5 and 18 h, while the urinary excretion of L-carnitine was measured for 48 h following the treatment. The results could indicate the presence of saturation phenomena in the absorption process for the oral doses used; specific research is required to ascertain this phenomena. The transfer of carnitine from central to extravascular volume is relatively rapid, as is its urinary excretion. The short half-life of carnitine and acetyl-carnitine can suggest the use of new forms of administration (slow-release).
Segre
G
G
Institute of Pharmacology, University of Siena, Italy.
Bianchi
E
E
Corsi
M
M
D'Iddio
S
S
Ghirardi
O
O
Maccari
F
F
D000284:Administration, Oral; D000328:Adult; D002331:Carnitine / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D008954:Models, Biological
D002331:Carnitine