Magnetic microparticles comprising organic substances
First Claim
1. A composition comprising microparticles, said microparticles comprising:
- (i) a magnetic substance;
(ii) a polymer associated with said magnetic substance, said polymer having functional groups ionizable to produce a charge sign; and
(iii) an ionizable organic compound, wherein said ionizable organic compound in aqueous medium is ionizable to the charge sign opposite to that of said polymer, and wherein said magnetic substance and said organic compound in totality constitute at least 50% of the microparticle dry mass, and wherein said microparticles are dispersible in water.
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Abstract
The invention provides for water-dispersible microparticles comprising magnetic material and organic substance, such as a pharmaceutical or a pigment, that constitute in totality at least 50%, or preferably more that 70%, of the dry mass of the particle. The method of making such microparticles is also provided, comprising coating of the magnetic material in an aqueous colloid form with a layer of a polyelectrolyte, and combining the coated colloid with the organic substance having ionic charge opposite to that of the polyelectrolyte. When the organic substance is poorly soluble in water, the combining comprises dissolving of the substance in a water-miscible organic solvent, and combining said solution with the polyelectrolyte-coated magnetic colloid. The magnetic pharmaceutical microparticles are useful for magnetically-guided drug delivery, and/or for non-invasive monitoring of the drug distribution in the body. Magnetic microparticles comprising dyes and pigments are useful in magnetic inks.
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Citations
27 Claims
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1. A composition comprising microparticles, said microparticles comprising:
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(i) a magnetic substance;
(ii) a polymer associated with said magnetic substance, said polymer having functional groups ionizable to produce a charge sign; and
(iii) an ionizable organic compound, wherein said ionizable organic compound in aqueous medium is ionizable to the charge sign opposite to that of said polymer, and wherein said magnetic substance and said organic compound in totality constitute at least 50% of the microparticle dry mass, and wherein said microparticles are dispersible in water. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 27)
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- 16. A method of making a microparticle-containing composition, said method comprising the step of contacting a magnetic substance dispersed in a liquid medium and having a charged polymer associated with said magnetic substance and ionized in said medium to attain a charge sign, with an ionizable organic compound attaining in said medium a charge sign opposite to that of said charged polymer, to effect formation of a microparticle.
Specification