Layer-by-layer deposition of shortened nanotubes or polyethylene glycol-derivatized nanotubes on liposomes: A tool for increasing liposome stability

A simple strategy for preparing potential drug delivery systems is presented which appears to be a good alternative to stealth liposomes in terms of stability in buffered aqueous solutions. Microcapsules have been prepared by deposition of shortened and polyethylene glycol-derivatized nanotubes onto positively charged multilamellar vesicles using the layer-by-layer technique. The stability of microcapsules has been determined turbidimetrically by measuring the rate of microcapsule breakdown induced by addition of a destabilizing agent such as the nonionic surfactant octaethyleneglycol mono-n-dodecyl ether. The investigated microcapsules have proven to be more stable than both pure liposomes and stealth liposomes. (C) 2007 Elsevier Ltd. All rights reserved.