Effect of cholesterol on the partitioning of amitriptyline into lipid membranes

Abstract

In this study, the effect of cholesterol on the partitioning of amitriptyline, a tricyclic antidepressant, into lipid bilayers composed of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), 1-stearoyl-2-oleoyl-sn-glycero-3-phosphocholine (SOPC), or 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) was examined using second derivative spectrophotometric method. As the results revealed, amitriptyline preferred to partition into the unsaturated DOPC followed by the mixed chain (SOPC) and the saturated (DSPC). The presence of 28 mol% cholesterol facilitated the partitioning of amitriptyline into the saturated and mixed chain lipids (DSPC and SOPC) but decreased the drug partitioning into the unsaturated lipid (DOPC). The study showed a significant role of cholesterol on the partitioning of a drug into the lipid membranes. Keywords: Amitriptyline, Cholesterol, Liposomes, Second Derivative Spectrophotometer