# US 11,439,725 B2 · Bioresorbable embolization microspheres

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- Number: US 11,439,725 B2
- Document ID: US11439725B2
- Status: Granted
- Kind: B2
- Application number: 16/206,199
- Filed: 2018-11-30
- Published: 2019-03-28
- Granted: 2022-09-13
- Earliest claimed: 2009-10-06
- Assignees: Regents of the University of Minnesota
- Applicants: Regents of the University of Minnesota
- Inventors: Jafar Golzarian; Lihui Weng
- Web page: https://patentgrep.com/patent/US11439725B2

## CPC

- A61L 24/08: Polysaccharides {(A61L24/043 takes precedence)}
- A61L 24/0015: {Medicaments; Biocides}
- A61P 9/00: Drugs for disorders of the cardiovascular system
- A61P 35/00: Antineoplastic agents
- A61L 2300/406: Antibiotics
- A61L 2300/622: Microcapsules
- A61L 2430/36: for embolization or occlusion, e.g. vaso-occlusive compositions or devices
- Y10T 428/2982: Particulate matter [e.g., sphere, flake, etc.]
- A61L: METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES (preservation of bodies or disinfecting characterised by the agents employed A01N; preserving, e.g. sterilising, food or foodstuffs A23; preparations for medical, dental or toiletry purposes A61K)
- A61P: SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

The present disclosure is generally directed to an embolic material which, in some embodiments, may be in the form of a microsphere or a plurality of microspheres. The embolic material generally comprises carboxymethyl chitosan (CCN) crosslinked with carboxymethyl cellulose (CMC). In some embodiments, the embolic material may further comprise a therapeutic agent, such as doxorubicin.

## Claims

### Claim 1

A microsphere, comprising:
carboxymethyl chitosan crosslinked with carboxymethyl cellulose, wherein a crosslinking density between the carboxymethyl chitosan and the carboxymethyl cellulose results in a fracture strain of the microsphere between about 70% and about 90%, and further defines a microsphere diameter between about 50 micrometers and about 2200 micrometers; and
a therapeutic agent.

### Claim 2 (depends on 1)

The microsphere of claim 1, wherein the therapeutic agent comprises a chemotherapeutic agent.

### Claim 3 (depends on 1)

The microsphere of claim 1, wherein the therapeutic agent comprises at least one positively charged functional group.

### Claim 4 (depends on 1)

The microsphere of claim 1, wherein the therapeutic agent comprises at least one of irinotecan, ambroxol, or doxorubicin.

### Claim 5 (depends on 1)

The microsphere of claim 1, wherein a concentration of the therapeutic agent is between about 0.3 milligram of therapeutic agent per milligram of dry microsphere and about 0.75 milligram of therapeutic agent per milligram of dry microsphere.

### Claim 6 (depends on 1)

The microsphere of claim 1, wherein the microsphere is substantially free of a small molecule crosslinking agent.

### Claim 7 (depends on 1)

The microsphere of claim 1, wherein the microsphere is compressible.

### Claim 8 (depends on 1)

The microsphere of claim 1, wherein the microsphere has a diameter between about 50 micrometers and about 1200 micrometers.

### Claim 9 (depends on 1)

The microsphere of claim 1 wherein the microsphere has a diameter between about 1600 micrometers and about 2200 micrometers.

### Claim 10

A microsphere comprising carboxymethyl chitosan crosslinked with carboxymethyl cellulose, wherein a crosslinking density between the carboxymethyl chitosan and the carboxymethyl cellulose results in a fracture strain of the microsphere between about 70% and about 90%, and further defines a microsphere diameter between about 50 micrometers and about 2200 micrometers, and wherein the microsphere has a compressibility sufficient to permit the microsphere to be introduced through a catheter or syringe.

### Claim 11 (depends on 10)

The microsphere of claim 10, wherein the microsphere comprises a diameter between about 50 micrometers and about 1200 micrometers.

### Claim 12 (depends on 10)

The microsphere of claim 10, wherein the microsphere comprises a diameter of between about 1600 micrometers and about 2200 micrometers.

### Claim 13 (depends on 10)

The microsphere of claim 10, wherein the microsphere further comprises a chemotherapeutic agent.

### Claim 14 (depends on 10)

The microsphere of claim 10, wherein the microsphere further comprises at least one of irinotecan, ambroxol, or doxorubicin.

### Claim 15 (depends on 13)

The microsphere of claim 13, wherein a concentration of the chemotherapeutic agent is between about 0.3 milligram of therapeutic agent per milligram of dry microsphere and about 0.75 milligram of therapeutic agent per milligram of dry microsphere.

### Claim 16 (depends on 10)

The microsphere of claim 10, wherein the microsphere is substantially free of a small molecule crosslinking agent.

### Claim 17

A microsphere comprising carboxymethyl chitosan crosslinked with carboxymethyl cellulose, wherein a crosslinking density between the carboxymethyl chitosan and the carboxymethyl cellulose results in a fracture strain of the microsphere between about 70% and about 90%, and wherein the microsphere has a diameter between about 50 micrometers and about 2200 micrometers; and
a therapeutic agent within the microsphere.