Multimeric particles
The invention provides multimeric particle comprising metal-containing particles covalently bonded to one another by linker groups wherein at least some of said linker groups are cleavable. The invention further provides a contrast agent comprising said multimeric particles, along with a method of improving contrast of an image using said contrast agent.
1. A multimeric particle comprising metal-containing particles covalently bonded to one another by linker groups wherein at least a portion of said linker groups are cleavable, wherein the multimeric particle is from more than 500 nm to 2 μm in diameter and wherein the average particle diameter of said metal-containing particles is from 1 nm to 200 nm.
2. A multimeric particle as claimed in claim 1 wherein at least a portion of the linker groups are enzymatically cleavable.
3. A multimeric particle as claimed in claim 1 wherein at least a portion of the linker groups are cleavable in vivo.
4. A multimeric particle as claimed in claim 1 wherein the linker groups comprise protein, peptide, polysaccharide, carbohydrate, ester, amide, ether and/or phosphate linkages.
5. A multimeric particle as claimed in claim 1 wherein the metal-containing particles comprise a metal or metal oxide core at least partially covered with a coating, said coating being covalently bonded to one or more linker groups.
6. A multimeric particle as claimed in claim 1 wherein the metal-containing particles are iron-containing particles.
7. A multimeric particle as claimed in claim 6 wherein the iron-containing particles comprise iron oxide.
8. A multimeric particle as claimed in claim 1 which is paramagnetic.
9. A multimeric particle as claimed in claim 1 which is superparamagnetic.
10. A contrast agent comprising a multimeric particle as claimed in claim 1 .
11. A contrast agent as claimed in claim 10 which further comprises a pharmaceutically acceptable excipient.