Although iodixanol gradients have been used widely since 1996 for the fractionation of these subcellular membrane compartments from mammalian cells, their application to the membranes from Drosophila has only been realized relatively recently (mainly since 2004). 

The methodology described in this OptiPrep™ Application Sheet employs a pre-formed 10%, 20%, 30% (w/v) iodixanol discontinuous gradient in a near-vertical rotor [1]. A crude membrane fraction was incorporated into each iodixanol solution and in this respect the method is similar to that devised by Yeaman et al [2] for MDCK cells. 

A more or less linear continuous gradient will from, partly by self-generation in the centrifugal field and partly by diffusion. Membranes are separated on the basis of buoyant density. It is quite likely that other iodixanol gradients, developed for mammalian cells would also be applicable, but this can only be verified by experimentation.