Lipid-coated condensed-phase microparticle composition
First Claim
1. A composition for release of a compound upon exposure to a target stimulus selected from the group consisting of pH, temperature, radiation, a ligand and an ion-channel activator, comprisingencapsulated microparticles having an average size between 0.05 and 5 microns, each encapsulated microparticle being composed of(i) an external lipid bilayer membrane effective to allow influx of external ions into the particle interior when exposed to said target stimulus,(ii) encapsulated within the lipid membrane, a condensed-phase microparticle which is composed of a matrix of crosslinked polyionic polymer filaments, and which is capable of decondensing to an expanded state when multivalent counterions also present within the matrix are replaced by monovalent counterions, and(iii) the compound to be released entrapped in the microparticle matrix, with said matrix in its condensed phase,whereby localized perturbation of the lipid membrane, and influx of monovalent counterions into the microparticle matrix, in response to said target stimulus, causes swelling and compound release from said microparticles.
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Abstract
A microparticle composition for use in compound delivery, when the composition is exposed to a selected target stimulus related to pH, temperature, radiation, or the presence of a selected ligand or ion-channel activator, is disclosed. The composition includes a condensed-phase particle matrix containing the compound to be delivered in entrapped form, and a stimulus-responsive lipid bilayer membrane formed around the matrix. Localized perturbation of the lipid membrane, and influx of monovalent counterions into the polymer matrix, in response to the selected target stimulus, causes matrix swelling and compound release from the particles.
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Citations
20 Claims
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1. A composition for release of a compound upon exposure to a target stimulus selected from the group consisting of pH, temperature, radiation, a ligand and an ion-channel activator, comprising
encapsulated microparticles having an average size between 0.05 and 5 microns, each encapsulated microparticle being composed of (i) an external lipid bilayer membrane effective to allow influx of external ions into the particle interior when exposed to said target stimulus, (ii) encapsulated within the lipid membrane, a condensed-phase microparticle which is composed of a matrix of crosslinked polyionic polymer filaments, and which is capable of decondensing to an expanded state when multivalent counterions also present within the matrix are replaced by monovalent counterions, and (iii) the compound to be released entrapped in the microparticle matrix, with said matrix in its condensed phase, whereby localized perturbation of the lipid membrane, and influx of monovalent counterions into the microparticle matrix, in response to said target stimulus, causes swelling and compound release from said microparticles.
Specification