Inhibitory effect of dexamethasone palmitate-low density lipoprotein complex on low density lipoprotein-induced macrophage foam cell formation.

We used low density lipoprotein (LDL) as a carrier of site-specific delivery of drugs to atherosclerotic lesions, prepared a dexamethasone palmitate (DP)-LDL complex, and examined the effect of the DP-LDL complex on foam cell formation of macrophages in vitro. LDL was isolated from human plasma and the DP-LDL complex was prepared by incubation in the presence of Celite 545. The complex contained about 50 mol of DP in 1 mol of LDL. When macrophages were incubated with LDL for 48 h, cholesterol ester was accumulated in the macrophages, indicating foam cell formation. This accumulation of cholesterol ester was significantly inhibited by incubation with the DP-LDL complex. The potency of the DP-LDL complex was similar to that of dexamethasone alone. The DP-LDL complex also significantly attenuated the accumulation of cholesterol ester induced by incubation with LDL prior to the incubation with the DP-LDL complex. These findings indicated that the DP-LDL complex showed similar characteristics to LDL, and the DP-LDL complex inhibited the foam cell formation of macrophages in in vitro experiments. This DP-LDL complex has a possibility as a drug-carrier complex for use in atherosclerosis.