Interactions Between Aminoglycosides and Phospholipids Using Liposomes: A Possible Mechanism of Nephrotoxicity

Interactions of aminoglycosides with phospholipids were estimated by the increase in turbidity of liposomes consisting of various phospholipids. The turbidity of liposomes containing negatively charged phospholipids was increased by gentamicin, the highest increase in turbidity being observed for phosphatidylinositol-4,5-diphosphate-containing liposomes. The extent of turbidity was dependent on the concentration of acidic phospholipid in the liposomal membrane as well as the number of amino groups of the aminoglycosides. The release of glucose from glucose-entrapped liposomes depended on the concentration of gentamicin. The turbidity of liposomes containing lipids extracted from rat renal cortex was also increased by aminoglycosides depending on the number of amino groups. From electron microscopic observations, the increase in turbidity of liposome suspensions was caused by liposome fusion.