Interactions between magnetic resonance imaging contrast agents and phospholipid monolayers

The adsorption of gadolinium chelated compounds as gadolinate (2(-)), (4RS) -[4-carboxy-5,8,11-tris(carboxymethyl)-1-phenyl-2-oxa-5,8,11triazatridecan- 13-oato (5(-))], dihydrogen compound with 1-deoxy-1(methylamino)-D-glucitol (1:2), Gd-BOPTA/dimeg, diethylene-triaminepentaacetate of gadolinium, Gd-D TPA, (4RS)-[4-carboxy-5,8,11-tris(carboxymethyl)-1-phenyl-2-oxa-5,8,11-tria zatridecan-13-oato(5)] gadolinato-disodium salt, Gd-BOPTA/disodium, (4s)-4- (4-ethoxybenzyl)-3,6,9-tris(carboxylatomethyl)3,6,9-triazaun decandioate ga dolinato, dimeglumine salt, Gd-EOB-DTPA and 3,3'-(4,5,6,7-tetrabromo-3-oxo- 1(3 H)-isobenzofuranylidene) bis[6-hydroxy-benzenesulfonic acid] disodium s alt, BSP, in self-assembled monolayers of phosphatidylcholine deposited on a mercury electrode was estimated by measuring the time dependence of the c harge which flows as a consequence of potential steps which should cause th e ion translocation across the monolayer, if these anionic compounds were a ble to freely diffuse across such a lipidic environment. In the time scale of our experimental measurements, namely 100 ms, no evidence of translocati on or significant perturbation of the lipid monolayers has been observed ex cept for the case of BSP. ils Gd-BOPTA and Gd-DPTPA are hepatobiliary contr ast agents these results seem to claim the hypothesis of the presence of a specific transport system which allows them to enter hepatocytes as it is t o be excluded a free diffusion of the complexes through the lipidic aggrega te. (C) 1998 Elsevier Science S.A. All rights reserved.