Fig. 2.

Schematic presentation of remote loading of bortezomib. Remote loading of bortezomib in PEGylated liposomes is depicted. Higher inside/lower outside pH gradient is created to facilitate bortezomib permeation into the liposome. Once inside, bortezomib encounters an entrapping agent (mannitol in this example), forming a boronate ester of bortezomib. The reaction is favored by basic pH inside the liposome.