Toshiyuki Sakakibara

Liposomal modification with uronate, which endows liposomes with long circulation in vivo, reduces the uptake of liposomes by J774 cells in vitro

For overcoming rapid removal of liposomes from the bloodstream, we developed reticuloendothelial system (RES)-avoiding liposomes modified with a uronic acid derivative, palmityl-D-glucuronide (PGlcUA). In this current study, we examined the in vitro interaction of PGlcUA-liposomes with J774 cells derived from mouse macrophages. Liposomal association with J774 cells at 37 degrees C did not increase compared with the binding at 4 degrees C when liposomes were modified with PGlcUA. RES-avoiding ability was not specifically endowed by glucuronate but by uronates in general, since palmityl-D-galacturonide showed a similar effect on liposomal clearance in vivo and liposomal uptake in vitro. These facts indicate that modification of the liposomal surface with uronic acid derivatives endows liposomes with a long circulation time in the bloodstream by reducing their uptake by macrophages.

Preparation of Liposome Using Instantaneous Vacuum-Dried Lipid Mixture

A new method was developed for preparing liposomes using an instananeous vacuum-dried lipid mixture. White lipid powder for preparing liposomes was easily obtained by spraying an organic solution of lipids into a vacuum at a temperature exceeding the boiling point of the organic solvent. The lipid mixture thus obtained could be quite easily hydrated and converted to liposomes possessing excellent trapping efficiency and trapped volume. The liposomes thus obtained was superior to that prepared by the freeze-dry or spray-dry method. The present method showed thus be readily applicable to industrial-scale production of liposomes.