Liposomal delivery system with photoactivatable triggered release
First Claim
1. A liposome comprising:
- a liposomal membrane consisting essentially of plasmalogens having a phospholipid with a vinyl ether functional group sufficiently close to an interface between the membrane and its environment or core that, when the vinyl ether functional group is cleaved to produce a product that forms a micelle in the membrane, pores are formed in the membrane through which the contents of the liposome may leave the liposome; and
a lysogenic substance that, in response to photoillumination or pH reduction, produces reactive oxygen species or hydrogen ions which cleave the vinyl ether functional group of the plasmalogen in response to photoillumination or pH reduction and form the pores in the membrane.
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Accused Products
Abstract
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 R1 and R2 are each long chain hydrocarbons containing 12-24 carbons.
80 Citations
27 Claims
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1. A liposome comprising:
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a liposomal membrane consisting essentially of plasmalogens having a phospholipid with a vinyl ether functional group sufficiently close to an interface between the membrane and its environment or core that, when the vinyl ether functional group is cleaved to produce a product that forms a micelle in the membrane, pores are formed in the membrane through which the contents of the liposome may leave the liposome; and a lysogenic substance that, in response to photoillumination or pH reduction, produces reactive oxygen species or hydrogen ions which cleave the vinyl ether functional group of the plasmalogen in response to photoillumination or pH reduction and form the pores in the membrane. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 23, 24, 25, 26, 27)
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20. A liposome, comprising:
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a liposomal membrane consisting essentially of a plasmalogen lipid that contains a vinyl ether functional group which, when cleaved, produces a micelle that forms a stable pore in the membrane; a lysogenic substance that locally reduces the pH or produces reactive oxygen species in response to illumination with light absorbed by the substance to cleave the vinyl ether functionality; and a therapeutic substance carried by the liposome and released from the liposome through the pore in the membrane after illumination. - View Dependent Claims (21, 22)
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Specification