(80c) Rapid Synthesis of Unilamellar Liposomes

Liposomes present as a versatile drug carrying vehicle, capable of loading hydrophobic and hydrophilic drugs, bio-compatibility, long-circulation, wide mono-disperse size range (from 10 nm to 10s of microns), and targeting specific tissues. Several methods of liposome synthesis are being employed that result in production of unilamellar vesicles in a laboratory time scale of minutes. These fast methods employ external driving to achieve a monodisperse population.  We present an alternate method of mono-disperse unilamellar liposome synthesis that results from spontaneous self-assembly of lipids in a solution  (and therefore does not require external driving), and which is rapid.  The lipids self-assemble when the solvent in which they are dissolved is rapidly replaced by a non-solvent (water) in a stationary phase interdiffusion.  There has also been no attempt to resonably compare the synthesis times for various methods of liposome production. We provide estimates of the time of synthesis of a single liposome for various methods known in the literature, and show that the present method is among the fastest of all the methods, and is much faster than earlier methods of spontaneous assembly.  The method is presently carried out in a batch mode, and requires device and process design to make it semi-batch or continuous.