BEHAVIORAL-EFFECTS OF VEHICLES - DMSO, ETHANOL, TWEEN-20, TWEEN-80, AND EMULPHOR-620

Experimental drugs and compounds that do not easily dissolve in water or saline are frequently combined with vehicles like solvents, deterge nts, or vegetable oils. Yet very little has been reported on the behav ioral effects of vehicles. In this study, we assessed the effects of a vegetable oil (emulphor-620), two detergents (Tween-20 and Tween-80), and two solvents [dimethyl sulphoxide (DMSO) and ethanol] on the loco motor activity in CD2F1 male mice. Locomotor activity was monitored fo r 12 h after vehicle administration (IF). The concentrations for each vehicle were expressed as percent of vehicle in saline (v/v). Emulphor -620 did not affect locomotor activity at any concentration tested (2% , 4%, 8%, 16%, and 32%). Tween-20 significantly decreased locomotor ac tivity at a concentration of 16% and Tween-80 at 32%. DMSO significant ly decreased locomotor activity at concentrations of 32% and 64%. In c ontrast, ethanol produced a biphasic behavioral response: increased ac tivity at a concentration of 16% and decreased activity at a concentra tion of 32%. These results will facilitate the selection and concentra tion of vehicles to be used in combination with experimental drugs or test agents.