Abstract
Viscous ethyl oleate (VEO) was prepared as an oily drug carrier by the addition of alminum stearate or ethyl cellulose. Since the rate of shear of VEO containing aluminum stearate was greatly and nonlinearly changed against the shearing stress compared to that containing ethyl cellulose, the latter was used for subsequent microvascular and organ distribution experiments in rats and hamsters. For infusion into the carotid artery in hamsters, neat ethyl oleate (EO, 4cP) or VEOs of various apparent viscosities (40, 80, 120cP-VEOs) embolized the vascular system in the cheek pouch, although arrival time to the site where the embolization was observed and the embolization period differed depending on the type of oily drug carrier. For infusion into the hepatic artery in rats, however, only 120cP-VEO embolized the vascular system in the liver. After infusion of the oily drug carrier containing 3H-oleic acid into the artery of hamster cheek pouch and rat liver, 30-50% of the radioactivity was gradually eliminated within 48h, whereas about 80% of the dose was rapidly eliminated after infusion to rat stomach and kidney. In addition, the amount of 120cP-VEO remaining in each organ 48h after infusion was higher than those of EO and 40 and 80cP-VEOs. Histological observation after infusion in rat liver revealed that 120cP-VEO slowly migrated from the artery or arteriole to the sinusoidal capillary region. These results suggest that 120cP-VEO can be used as a drug carrier because of its function of vascular embolization and high retention in a targeted tissue.
