Novasome microvesicles are paucilamellar vesicles that can be formed from many bio-compatible, single-tailed amphiphiles, as well as phopholipids. Novasome microvesicles have up to seven bilayer membranes, each composed of these amphiphilic molecules, surrounding a large amorphous core. The core accounts for most of the Novasome vesicle volume, providing a high capacity for water soluble and water immiscible substances, as well as some small solid particles. Because of these unique traits, Novasome microvesicles have many advantages over other liposomes.
Novasome® microvesicles are generally 200-700 nanometers in size, depending upon a wide variety of membrane constituents individually chosen for each particular purpose. Their size distribution is very uniform, and encapsulation efficiency can be nearly 100% for lipid cargo and 85% for aqueous materials. Finely divided insoluble particles (ie. titanium dioxide, diamonds, insoluble pharmaceuticals) can also be encapsulated. Novasome® microvesicles are inherently stable, and can be tailored to be stable at pH ranges from 2-13, and temperature ranges from liquid nitrogen to above the boiling point of water.
THE NOVASOME MICROVESICLE DELIVERY PROCESS
Lipid vesicle freeze fracture electron micrograph. A chip has been broken off the structure clearly showing membrane bilayers surrounding a lipid-filled cargo space.
Novasome® microvesicles can be made to have no net surface, a net negative or a net positive charge. A net positive charge is desired for adherence of microvesicles to the negatively charged skin, hair or mucous membranes. Thus, it is at times desirable to make Novasome® microvesicle walls with a composition close to that of stratum corneum lipids to deliver such lipids into the skin.
A non-phosphid outer membrane of the Novasome® microvesicle is composed of 5 to 7 lipid bilayers (A) and the inner cargo hold (B).
Particles of the active substances (C) pass from the bilayer (D) to bilayer through the aqueous suspension (E) separating the layers. This process provides a continuous release of the cargo.
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