# US 10,478,527 B2 · Biodegradable implant

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- Number: US 10,478,527 B2
- Document ID: US10478527B2
- Status: Granted
- Kind: B2
- Application number: 15/757,475
- Filed: 2016-09-05
- Published: 2019-01-24
- Granted: 2019-11-19
- Earliest claimed: 2015-09-04
- Assignees: University of the Witwatersrand, Johannesburg
- Applicants: University of the Witwatersrand, Johannesburg
- Inventors: Viness Pillay; Yahya Essop Choonara; Pradeep Kumar; Lisa Claire Du Toit; Poornima Ramburrun
- Web page: https://patentgrep.com/patent/US10478527B2

## CPC

- A61L 27/48: with macromolecular fillers
- A61L 27/16: obtained by reactions only involving carbon-to-carbon unsaturated bonds
- A61L 27/20: Polysaccharides
- A61L 27/52: Hydrogels or hydrocolloids
- A61L 27/54: Biologically active materials, e.g. therapeutic substances {(A61L27/227 takes precedence)}
- A61L 27/56: Porous materials, {e.g. foams or sponges}
- A61L 27/58: Materials at least partially resorbable by the body
- A61L 2400/12: Nanosized materials, e.g. nanofibres, nanoparticles, nanowires, nanotubes; Nanostructured surfaces
- A61L 2430/32: for nerve reconstruction
- 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)

## Abstract

This invention relates to biodegradable implants comprising a hydrogel carrier matrix having dispersed therein a multitude of particles, wherein each of the multitude of particles and/or the hydrogel carrier matrix includes an active pharmaceutical ingredient (API) for the treatment of transected peripheral nerve injuries. Each of the multitude of particles and/or the hydrogel carrier matrix includes pristine polymer particles, preferably the pristine polymer particles may be polymethylmethacrylate polymers and derivatives thereof, preferably poly(methacrylic-co-methyl methacrylate) (PMMA). The spheroidal particles may each be formed from an outer shell including a chitosan (CHT) poly(methacrylic-co-methyl methacrylate) (PMMA) polyelectrolyte complex (CHT-PMMA-PEC) and an inner core including crosslinked chitosan having dispersed therein PMMA nanoparticles.

## Claims

### Claim 1

A biodegradable implant comprising a hydrogel carrier matrix having dispersed therein a multitude of spheroidal particles, each spheroidal particle including a crosslinked cationic chitosan (CHT) having dispersed therein anionic poly(methacrylic-co-methyl methacrylate) (PMMA) nanoparticles, and wherein the hydrogel carrier matrix comprises at least one anionic polysaccharide.

### Claim 2 (depends on 1)

The biodegradable implant according to claim 1, wherein each of the spheroidal particles includes dispersed therein a first active pharmaceutical ingredient (API).

### Claim 3 (depends on 2)

The biodegradable implant according to claim 2, wherein the spheroidal particles each includes an outer shell including a chitosan (CHT) poly(methacrylic-co-methyl methacrylate) (PMMA) polyelectrolyte complex (CHT-PMMA-PEC) and an inner core including crosslinked chitosan having dispersed therein PMMA nanoparticles.

### Claim 4 (depends on 3)

The biodegradable implant according to claim 3, wherein the outer shell of CHT-PMMA-PEC is formed in situ when the spheroidal particles contact an aqueous medium providing constant release of the first API therefrom.

### Claim 5 (depends on 4)

The biodegradable implant according to claim 4, wherein the outer shell of CHT-PMMA-PEC and/or the inner core includes pores.

### Claim 6 (depends on 5)

The biodegradable implant according to claim 5, wherein the pores are formed in situ when the outer shell and/or the inner core contacts an aqueous medium of pH between 5 and 9 therein dissolving the PMMA to provide pores, which pores provide for facilitating dissolution of the first API out of the spheroidal particle.

### Claim 7 (depends on 2)

The biodegradable implant according to claim 2, wherein the hydrogel carrier matrix further includes a second active pharmaceutical ingredient (API).

### Claim 8 (depends on 7)

The biodegradable implant according to claim 7, wherein the first API and the second API is the same API or alternatively different APIs.

### Claim 9 (depends on 1)

The biodegradable implant according to claim 1, wherein the at least one anionic polysaccharide includes xanthan gum and gellan gum forming a xanthan gum-gellan gum blend.

### Claim 10 (depends on 9)

The biodegradable implant according to claim 9, wherein the hydrogel carrier matrix further comprises a crosslinking agent forming a crosslinked xanthan gum-gellan gum matrix.

### Claim 11 (depends on 1)

The biodegradable implant according to claim 1, wherein the hydrogel carrier matrix further includes poly(methacrylic-co-methyl methacrylate) (PMMA) nanoparticles.

### Claim 12 (depends on 11)

The biodegradable implant according to claim 11, wherein the hydrogel carrier matrix includes pores.

### Claim 13 (depends on 12)

The biodegradable implant according to claim 12, wherein the pores are formed in situ when the hydrogel carrier matrix contacts an aqueous medium of pH between 5 and 9 therein dissolving PMMA to provide pores.