School of Pharmacy, Tokyo University of Pharmacy and Life Science, 1432-1 Horinouchi, Hachioji, Tokyo 192-03, Japan
Abstract:
A high-performance liquid chromatographic procedure has been developed for the determination of [d-Ala2, d-Leu5]enkephalin (DADLE) and the fragments containing d-leucine in rat blood. The procedure was applied to the determination of blood levels of [3H-d-Leu5]DADLE and the C-terminal fragments after intravenous administration of [3H-d-Leu5]DADLE to a rat. Unlabelled DADLE and the C-terminal fragments were spiked as carriers to rat blood samples and the blood samples were extracted with 1% trifluoroacetic acid in methanol. The recoveries from rat blood were quantitative for all compounds. DADLE and the C-terminal four fragments were well separated on a reversed-phase column with gradient elution using a mobile phase composed of 0.14% HClO4 and acetonitrile.