A new method of producing paucilamellar lipid vesicles has been developed. The vesicles are made of non-phospholipid surfactants. The paucilamellar lipid vesicles have 2-8 lipid bilayers surrounding a central cavity which may be filled with either an aqueous-based solution or an oil or wax.

Micro-Pak, Inc.

Paucilamellar lipid vesicles

A triggered release liposomal delivery system is disclosed that selectively releases its contents in response to illumination or reduction in pH. The liposomes contain an amphipathic lipid, such as a phospholipid, having two chains derived from fatty acid that allow the lipid to pack into a bilayer structure. One or both of the alkyl chains contains a vinyl ether functionality that is cleaved by reactive oxygen species (ROS) or acid. A photosensitizer is incorporated into the liposomal cavity or membrane, and produces ROS or acid when illuminated to cleave the vinyl ether functionality and disrupt the liposomal membrane to release the vesicle contents. The lipid is preferably a plasmalogen, for example ##STR1## wherein R.sub.1 and R.sub.2 are each long chain hydrocarbons containing 12-24 carbons.

Liposomal delivery system with photoactivatable triggered release

Biocompatible fluorocarbon emulsions having fluorocarbon in concentrations of from 75% weight per volume to 125% weight per volume have small, biocompatible particle size stability through heat sterilization with one emulsifying agent, including phospholipids, in concentrations of from 3% to 7% weight per volume. The single emulsifying agent can be hydrogenated lecithins and synthesized lecithins. Fluorocarbon emulsions having fluorocarbon in concentrations of from 40% weight per volume to 125% weight per volume have stability of partial pressure of oxygen and of partial pressure of carbon dioxide through heat sterilization and storage for extended periods of time after having been oxygenated with dissolved oxygen. A method of preparing biocompatible fluorocarbon emulsions includes preparing a mixture of an emulsifying agent, osmotic agent, buffering agent, aqueous phase and fluorocarbon, forcing the mixture under high pressure into a cavity, against a surface and around a lip to cause turbulence and possibly cavitation to form high fluorocarbon concentration emulsions that are stable through heat sterilization; and, even when oxygenated, maintain substantially stable partial pressures of oxygen and of carbon dioxide, and substantially stable pH. A method of oxygenating high fluorocarbon concentration emuslions includes placing a measured amount of the emulsion in a container and causing the emulsion to form a thin film around the inner surface of the container when the oxygen is injected. An alternative method of oxygenating the high fluorocarbon concentration emulsion includes a two container system where one container, permeable to the to be dissolved gas, is formed within the other, and the emulsion is injected in one container and the to be dissolved gas is injected into the other container.

phospholipid/karies

Paucilamellar lipid vesicles

Paucilamellar lipid vesicles

Paucilamellar lipid vesicles

Liposomal delivery system with photoactivatable triggered release

Dissolution of gas in a fluorocarbon liquid

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