Hexosomes: a novel drug delivery system

Polar lipids and various surfactants exhibit rich phase behavior depending on the composition of the lipids and the physicochemical conditions. Lamellar (L(alpha)), hexagonal (Inverted [H(II)]) and normal or inverted cubic (bicontinuous or micellar) structures are some of the most common lyotropic liquid crystalline phases. Hexosomes are the reverse hexagonal phases comprised of hexagonally close-packed infinite water layers covered by surfactants monolayer. Hexosomes (dispersed HII phases) due to their special structural properties have potential to be used as alternative delivery vehicle for pharmaceuticals. Biologically active molecules can either be accommodated within the aqueous domains or can be directly coupled to the lipid hydrophobic moieties oriented radially outwards from the centre of the water rods. Due to these special properties of hexosomes, they are used to improve solubility of poorly water soluble drugs and to transport therapeutic peptides and proteins by oral, transdermal, and parenteral routes. This article includes various methods of preparation of hexosomes and their application in drug delivery through various routes.