Search

EP-3897733-B1 - CROSSLINKED POLYSACCHARIDES AND RELATED METHODS

EP3897733B1EP 3897733 B1EP3897733 B1EP 3897733B1EP-3897733-B1

Inventors

  • PROVONCHEE, RICHARD
  • GITTO, Valentino
  • MILLER, LEONARD

Dates

Publication Date
20260513
Application Date
20191220

Claims (12)

  1. A method of forming a crosslinked agarose gel, the method comprising: dissolving an agarose in a solvent to form a solution containing agarose; gelling the solution containing agarose to form a gelled agarose; modifying the gelled agarose to have an agarose concentration of between 10% and 80% by weight, wherein modifying the gelled agarose comprises at least partially dehydrating the gelled agarose to yield a gelled agarose having an agarose concentration of between 10% and 80% by weight; irradiating the gelled agarose having an agarose concentration of between 10% and 80% to form a crosslinked agarose gel, wherein irradiating is accomplished by exposure to one or more of the following: gamma radiation, x-rays, or beta radiation and the gelled agarose is irradiated with at least 5 kilograys (kGy) of radiation.
  2. The method of claim 1, wherein the agarose is selected from the group consisting of: purified agarose, modified agarose, and derivatized agarose.
  3. The method of claim 1, wherein the solvent comprises water or water and, glycerine or water and a glycol.
  4. The method of claim 1, wherein the gelled agarose has an agarose concentration of between 20% and 60% by weight.
  5. The method of claim 1, further comprising mixing the crosslinked agarose gel with hyaluronic acid prior to administering to a patient.
  6. The method of claim 1, wherein gelling the solution containing agarose to form a gelled agarose comprises: gelling the solution containing agarose as a foam or as an open matrix structure, applying the solution containing agarose as a coating on a substrate and then gelling the solution while on the substrate, and/or imbibing the solution containing agarose into an absorbent material and then gelling the solution containing agarose on or in the absorbent material.
  7. The method of claim 1, wherein gelling the solution containing agarose is accomplished through an extrusion process.
  8. The method of claim 1, further comprising incorporating one or more additives into the crosslinked agarose gel and the one or more additives are selected from the group consisting of pharmaceutical agents, cells, and tissue.
  9. The method of claim 1, further comprising incorporating one or more additives into the solution containing agarose, wherein the one or more additives comprise hyaluronic acid.
  10. The method of claim 1, wherein the solution containing agarose also contains hyaluronic acid and the crosslinked agarose gel also includes crosslinked hyaluronic acid.
  11. The method of claim 10, wherein the solution containing agarose and hyaluronic acid has an agarose concentration of between 1% and 2% by weight.
  12. The method of claim 11, further comprising degrading the hyaluronic acid of the crosslinked gel by exposing the crosslinked gel to a hyaluronidase enzyme.

Description

BACKGROUND Crosslinking is the process of chemically joining two or more polymer chains together through a covalent or ionic bond. Various mechanical properties of a polymer can be modified by crosslinking. For example, crosslinking a material to a low crosslink density can decrease the viscosity of polymer melts, while crosslinking to an intermediate crosslink density can transform a gummy polymer into a material with elastomeric properties and potentially high strength. In some cases, very high crosslink densities can cause a material to become rigid or glassy. Numerous crosslinking techniques are known, including processes that rely on heat, pressure, change in pH, or radiation to initiate the crosslinking process. Some documents of the state of the art that relate to polysaccharide gels and their preparation method are cited below: Document US2013/078299 A1 discloses crosslinked hydrogel-based transdermal pharmaceutical formulations and parches useful for administering a variety of drugs to patients. The transdermal patches here employ crosslinked-hydrogels generated through irradiation and may be formed from a variety of polymeric compounds and include substantial levels of water to improve skin tolerance by the patient. Documents US4684558 A relates to an adhesive hydrophilic gel consisting essentially of a crosslinked polyethylene oxide dispersed uniformly in water. Document WO2018/213408 A1 discloses a composition comprising an agaroid structure made from essentially solid agaroid having a plurality of interconnected pores and one or more beneficial agents. Said structure is useful for treating a condition of a mammal. Document US6031017 A refers to an injectable photocured crosslinked-hyaluronic acid hydrogel obtained by irradiation with ultraviolet rays of a photoreactive hyaluronic acid derivative and to a biomedical material comprising said hydrogel. Document: YOSHII et al.: "Hydrogels of polysaccharide derivatives crosslinked with irradiation at paste-like condition", Nuclear Instruments and Methods in Physics Research B, 208 (2003) 320-324 discloses that water-soluble polysaccharides derivatives such as carboxymethylcellulose (CMC), carboxymethylstarch (CMS) and carboxymethylchitin (CMCT), carboxymethylchitosan (CMCTS) lead to radiation crosslinking at high concentrated aqueous solution. It was proved that the crosslinking was remarkably affected by their concentration. Document WO 2018/212718 A1 relates to a method for making hydrogel-based soft robots with stretchable coating. Document: Qiang Chen ET AL: "Fracture of the Physically Cross-Linked First Network in Hybrid Oouble Network Hydrogels", MACROMOLECULES, 47(6), (2014), 2140-2148, relates to an study of the fundamental understanding of the fracture processes and toughening mechanism of double network hydrogels based in agar and polyacrylamide. Document: Krommelbein Catharina ET AL: "Impact of high-energy electron irradiation on mechanical, structural and chemical properties of agarose hydrogels", Carbohydrate Polymers, 263 (2021), 117970, relates to a study about electron radiation treatment of agarose hydrogels to evaluate the effects on physical, structural and chemical properties. Document: "Radiation effects on physically cross-linked agarose hydrogels", Nuclear science and techniques, 1 January 2015 (2015-01-01 ), pages 48-52, relates to three-dimensional gels, in particular cross-linked agarose hydrogels and the study of their radiation resistance and radiolysis mechanism. Document WO 2018/231718 A1 relates to a dermal filler composition comprising a cross-lined structure of hyaluronic acid, agarose , water and additives. SUMMARY This disclosure relates to methods of crosslinking polysaccharides as well as the resulting crosslinked compositions. In particular, the subject disclosure describes methods of irradiating polysaccharides, particularly agarose, while in a gelled state to achieve a desired level of crosslinking. As used herein, the term "polysaccharide" refers to a polymeric carbohydrate having the general formula Cx(H2O)y, such as, for example, starch, dextrin, cellulose, hemicellulose, polydextrose, inulin, beta-glucan, pectin, psyllium husk mucilage, mannan, beta-mannan, carob, fenugreek, guar, tara gum, glucomannan, gum acacia, karaya, tragacanth, arabinoxylan, gellan, xanthan, alginate, agarose, carrageenan, agar, hyaluronic acid, chitin, and chitosan. Many example embodiments in which the polysaccharide agarose is used are described in detail herein. However, the subject disclosure is not intended to be so limited. Specifically, although examples in which agarose is used, any other suitable type of polysaccharide may alternatively or additionally be used. For example, embodiments in which hyaluronic acid is used are also of interest and described in detail herein. Although irradiation techniques have previously been applied to some polysaccharides for crosslinking purposes, this type of crosslinking process (as previ