Comparison of pharmacokinetics of L-carnitine, Acetyl-L-carnitine and Propionyl-Lcarnitine after single oral administration of L-carnitine in healthy volunteers

摘要

Purpose: To investigate the pharmacokinetics of Lcarnitine (LC) and its analogues, acetyl-L-carnitine (ALC) and propionyl -L-carnitine (PLC) in healthy volunteers after single L-carnitine administration. Methods: Liquid L-carnitine (2.0 g) was administered orally as a single dose in 12 healthy subjects. Plasma and urine concentrations of L-carnitine, ALC and PLC were detected by HPLC. Results: The maximum plasma concentration (Cmax) and area under the curve (AUC_(0-propor. to)) of L-carnitine was 84.7+-25.2 mumolcentre dot L-1centre dot h and 2676.4+-708.3 mumolcentre dot L-1centre dot h, respectively. The elimination half-life of L-carnitine and the time required to reach the Cmax (Tmax) was 60.3+-15.0 and 3.4+-0.46 h, respectively. The Cmax of ALC (12.9+-5.5 mumolcentre dot L-1) and PLC (5.08+-3.08 mumolcentre dot L-1) was lower than Lcarnitine (P<0.01), so as the AUC_(0-propor. to) (166.2+-77.4 and 155.6+-264.2mumolcentre dot L-1centre dot h, respectively, P<0.01). The half-life of ALC (35.9+-28.9h) and PLC (25.7+-30.3 h) was also shorter than L-carnitine (P<0.01). The 24h accumulated urinary excretion of L-carnitine, ALC and PLC were 613.5+-161.7, 368.3+-134.8 and 61.3+-37.8mumol, respectively. Conclusion: L-carnitine has a greater maximum plasma concentration than ALC and PLC. L-carnitine also has a longer half-life than ALC and PLC. These data may have important implications in the designing of dosing regimens for L-carnitine or its analogues, such as ALC or PLC.