Condensed-phase microparticle composition and method
First Claim
1. A method of achieving controlled release of a cationic therapeutic compound from microparticles made from anionic polymers, said microparticles having the property that they undergo transition from a swelled, decondensed state to a condensed state in the presence of Ca+2 ions, and rapid transition back to the decondensed state when exposed to monovalent cations, said method comprisingmixing said cationic therapeutic compound with a suspension of microparticles (i) having average sizes in a selected size range between 0.05 and 5.0 microns, and (ii) composed of a condensed-phase matrix of crosslinked polyionic polymer filaments capable of expanding to a decondensed phase in the presence of monovalent counterions, said mixing being carried out with the particles in their decondensed state, such that said cationic therapeutic compound becomes incorporated into the matrix of the microparticles, andcondensing the microparticles by addition of polycations containing at least three charged groups, said polycations being effective to delay the release of the compound from the microparticles when the microparticles are exposed to monovalent cations.
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Abstract
An microparticle composition and its method of use in drug delivery and diagnostic applications are disclosed. Also disclosed are methods of storing and administering drug compounds at high concentration in condensed-phase microparticles.
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Citations
3 Claims
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1. A method of achieving controlled release of a cationic therapeutic compound from microparticles made from anionic polymers, said microparticles having the property that they undergo transition from a swelled, decondensed state to a condensed state in the presence of Ca+2 ions, and rapid transition back to the decondensed state when exposed to monovalent cations, said method comprising
mixing said cationic therapeutic compound with a suspension of microparticles (i) having average sizes in a selected size range between 0.05 and 5.0 microns, and (ii) composed of a condensed-phase matrix of crosslinked polyionic polymer filaments capable of expanding to a decondensed phase in the presence of monovalent counterions, said mixing being carried out with the particles in their decondensed state, such that said cationic therapeutic compound becomes incorporated into the matrix of the microparticles, and condensing the microparticles by addition of polycations containing at least three charged groups, said polycations being effective to delay the release of the compound from the microparticles when the microparticles are exposed to monovalent cations.
Specification