Pharmacokinetics and organ distribution of liposome-encapsulated L-carnitine in rats.

The pharmacokinetics and organ distribution of 3H-L-carnitine (CAS 541-15-1) were investigated in rats following direct intravenous administration of the drug substance and administration of the drug encapsulated in liposomes, respectively. The retention in the blood system of carnitine in liposomes, was significantly higher, namely up to 300% as compared to the standard administration. The half-life of distribution t1/2 alpha to 0.68 h (+154%), the terminal half-life t1/2 beta to 7.94 h (+140%), whereas the total clearance decreased by 400% as compared with the standard carnitine administration. Carnitine, in the novel dosage form, accumulated to a higher extent in the liver (156%) and spleen (336%), while the concentration in lung (52%), heart (55%) and muscle tissue (54%) decreased markedly relative to the standard. The novel dosage form is stable in vitro (t1/2 4 degree C = 187 days) as well as in vivo and, thus, may be successfully used in the therapy of carnitine deficiency, for instance in patients with renal failure or liver disease.