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US-12624129-B2 - Crosslinked butyrate or butyrate-formate derivatives of hyaluronic acid and the crosslinking thereof

US12624129B2US 12624129 B2US12624129 B2US 12624129B2US-12624129-B2

Abstract

The present invention relates to a process for the preparation of crosslinked hyaluronic acid butyrate or crosslinked hyaluronic acid butyrate-formate or an acceptable salt thereof, wherein the process comprises the crosslinking reaction of hyaluronic acid butyrate or hyaluronic acid butyrate-formate or a pharmaceutically acceptable salt thereof in an organic solvent with a carboxyl activating reagent, characterized in that the hyaluronic acid butyrate or hyaluronic acid butyrate-formate or pharmaceutically acceptable salt thereof is a mixture of a high-molecular-weight polysaccharide and a low-molecular-weight polysaccharide.

Inventors

  • Marco Mastrodonato
  • Luca Stucchi
  • Alessandra Sechi
  • Fabrizio Picotti
  • Rita Gianni

Assignees

  • BMG PHARMA S.P.A.

Dates

Publication Date
20260512
Application Date
20201119
Priority Date
20191120

Claims (20)

  1. 1 . A process for preparing crosslinked hyaluronic acid butyrate or crosslinked hyaluronic acid butyrate-formate or an acceptable salt thereof, the process comprising: crosslinking hyaluronic acid butyrate or hyaluronic acid butyrate-formate or a pharmaceutically acceptable salt thereof in an organic solvent with a carboxyl group activating reagent and a base forming a reaction mixture, buffering said reaction mixture to a pH of 7.2; and obtaining said crosslinked hyaluronic acid butyrate or said crosslinked hyaluronic acid butyrate-formate or said acceptable salt thereof, wherein the hyaluronic acid butyrate or hyaluronic acid butyrate-formate or a pharmaceutically acceptable salt thereof is a mixture of a high molecular weight polysaccharide having a weight average molecular weight ranging between 1000 kDa and 10000 kDa and a low molecular weight polysaccharide having a weight average molecular weight ranging between 1 kDa and 900 kDa, and wherein the process comprises sterilizing in an autoclave at 121° C. for 15 minutes.
  2. 2 . The process according to claim 1 wherein the low molecular weight polysaccharide has a weight average molecular weight ranging from 1 kDa to 500 kDa and the high molecular weight polysaccharide has a weight average molecular weight ranging from 1000 kDa to 6000 kDa.
  3. 3 . The process according to claim 2 wherein the low molecular weight polysaccharide has a weight average molecular weight ranging from 50 kDa to 300 kDa and the high molecular weight polysaccharide has a weight average molecular weight ranging from 1000 kDa to 2000 kDa.
  4. 4 . The process according to claim 1 , wherein the high molecular weight polysaccharide and the low molecular weight polysaccharide are present in an 80:20 to 20:80 weight ratio.
  5. 5 . The process according to claim 1 , wherein the hyaluronic acid butyrate or the hyaluronic acid butyrate-formate or a pharmaceutically acceptable salt thereof has a degree of substitution ranging from 0.1 to 2.2.
  6. 6 . The process according to claim 1 , wherein the acceptable salt of hyaluronic acid butyrate or of hyaluronic acid butyrate-formate is sodium, potassium lithium or a quaternary ammonium salt.
  7. 7 . The process according to claim 6 wherein the acceptable salt is the sodium salt.
  8. 8 . The process according to claim 6 , wherein said quaternary ammonium salt is tetrabutylammonium.
  9. 9 . The process according to claim 1 , wherein the organic solvent is selected from basic polar aprotic solvents selected from the group consisting of N,N-dimethylformamide, dimethylacetamide, dimethylsulphoxide, N-methylpyrrolidone and formamide.
  10. 10 . The process according to claim 9 wherein the organic solvent is formamide.
  11. 11 . The process according to claim 1 wherein the carboxyl group activating reagent is selected from the group consisting of carbonyl diimidazole, 1,1′-carbonyl-di-(1,2,4-triazole), 1,1′-oxalylimidazole, 1,1′-thiocarbonylimidazole, 1,1′-carbonyl bis(2-methylimidazole), N-hydroxysuccinimide, p-nitrophenol, p-nitrophenyl trifluoroacetate, 2-halo-N-alkylpyridine salts and acyl halides.
  12. 12 . The process according to claim 11 wherein the carboxyl group activating reagent is carbonyl diimidazole.
  13. 13 . The process according to claim 1 , wherein the base is selected from inorganic bases selected from carbonates, bicarbonates and hydroxides of an alkaline or alkaline-earth metal, aromatic or aliphatic organic bases comprising at least one atom of trisubstituted nitrogen selected from such as pyridine or its homologues, basic amines selected from triethylamine, N-methyl-piperazine or dimethylaminopyridine, or the alkaline or alkaline-earth metal salt of an organic acid selected from sodium or potassium acetate.
  14. 14 . The process according to claim 13 wherein the base is sodium carbonate or dimethylaminopyridine.
  15. 15 . The process according to claim 13 , wherein said hydroxides of an alkaline or alkaline-earth metal is selected from sodium, potassium or magnesium.
  16. 16 . The process according to claim 13 , wherein said homologue of pyridine is collidine.
  17. 17 . The process according to claim 1 , wherein the reaction mixture is kept at a temperature ranging between 20° C. and 30° C. for a period ranging between 4 and 24 hours.
  18. 18 . Crosslinked hyaluronic acid butyrate or crosslinked hyaluronic acid butyrate-formate or an acceptable salt thereof obtained by the process according to claim 1 .
  19. 19 . A pharmaceutical or cosmetic formulation or medical device comprising crosslinked hyaluronic acid butyrate or crosslinked hyaluronic acid butyrate-formate or a pharmaceutically acceptable salt thereof according to claim 18 , and at least one pharmaceutically acceptable excipient and/or carrier.
  20. 20 . The pharmaceutical or cosmetic formulation or medical device according to claim 19 containing a local anesthetic.

Description

This application is a U.S. national stage of PCT/IB2020/060888 filed on 19 Nov. 2020, which claims priority to and the benefit of Italian Patent Application No. 102019000021693 filed on 20 Nov. 2019, the contents of which are incorporated herein by reference in their entireties. The present invention relates to a process for the preparation of crosslinked hyaluronic acid butyrate or crosslinked hyaluronic acid butyrate-formate or a salt thereof, the product obtained by said process, and its formulation for pharmaceutical or cosmetic use or as a medical device. In particular, the present invention relates to crosslinking of a combination of different molecular weights of hyaluronic acid butyrate or hyaluronic acid butyrate-formate or a salt thereof which surprisingly gives rise to a polymer with a different rheological profile from that of a polymer obtained by combining the same polymers, previously crosslinked. The crosslinked butyric-formic esters of hyaluronic acid prepared by said process have better viscoelastic properties than gels obtained by combining polysaccharides with different molecular weights previously crosslinked, and can therefore be advantageously used in the pharmaceutical and dermocosmetic fields and as medical devices, in particular as injectables. STATE OF THE ART Hyaluronic acid is a glycosaminoglycan consisting of repeating units of glucuronic acid and N-acetylglucosamine bonded together or, alternatively, via glycoside bonds β1→4 and β1→3. Hyaluronic acid is an essential element of connective tissue, and is also present in synovial fluid, vitreous humour and umbilical cord. WO98/23648 discloses the preparation of hyaluronic acid butyrate (SHB) wherein the hydroxyl groups of hyaluronic acid are esterified with butyric acid residues. Hyaluronic acid butyrate has anti-inflammatory, anti-proliferative and skin-protecting properties as a skin elasticiser and moisturizer. WO2009/068215 discloses the preparation of mixed butyric-formic esters of hyaluronic acid and their use in dermocosmetics, with skin-protecting and anti-inflammatory activity. The mixed esters are prepared with butyric anhydride and formamide (FA), with N,N-dimethylamino pyridine (N,N-DMAP) as basic catalyst. EP 341745 discloses the preparation of autocrosslinked hyaluronic acid starting with hyaluronic acid or hyaluronic acid wherein the carboxyl groups are partly esterified with various types of alcohols. The carboxyl function of hyaluronic acid (or of the ester derivatives thereof, defined as “external esters”) is involved in the formation of intra- or intermolecular esters with the alcohol hydroxyls of the repeating units of hyaluronic acid, with consequent crosslinking (defined as “autocrosslinking”). WO2008/081255 discloses the preparation of autocrosslinked hyaluronic acid characterized by the concomitant presence of esters with non-polysaccharide carboxylic acids, including butyric-formic acid, and esters between the acid group and the alcohol groups of the initial polysaccharide with crosslinking between the polysaccharide chains. EP 2614090 discloses cooperative hybrid complexes between low-molecular-weight and high-molecular-weight hyaluronic acid, wherein the hyaluronic acid molecules in solution are characterized by cooperative interaction based on the formation of hydrophobic bonds and intra- and inter-chain hydrogen bonds, the extent of which depends on the molecular weight of the polysaccharide. It has now been discovered that crosslinking hyaluronic acid butyrate or hyaluronic acid butyrate-formate with different molecular weights increases the chemical and biological stability of the polysaccharide, at the same time providing an improved rheological profile, which is particularly advantageous for applications in the pharmaceutical and dermocosmetic fields and as a medical device, in particular as an injectable. DESCRIPTION OF THE INVENTION The object of the present invention is a process for the preparation of crosslinked hyaluronic acid butyrate or crosslinked hyaluronic acid butyrate-formate or an acceptable salt thereof, wherein the process comprises the reaction of hyaluronic acid butyrate or hyaluronic acid butyrate-formate or a pharmaceutically acceptable salt thereof in an organic solvent with a carboxyl group activating reagent and a base, characterized in that the hyaluronic acid butyrate or hyaluronic acid butyrate-formate or pharmaceutically acceptable salt thereof is a mixture of a high-molecular-weight polysaccharide having a weight-average molecular weight ranging from 1000 kDa to 10000 kDa, preferably from 1000 kDa to 6000 kDa, and more preferably from 1000 kDa to 2000 kDa, and a low-molecular-weight polysaccharide having a weight-average molecular weight ranging from 1 kDa to 900 kDa, preferably from 10 kDa to 500 kDa, and more preferably from 50 kDa to 300 kDa. The degree of substitution (DS), defined as the ratio between the number of butyric or butyric-formic acid residues per GlcNAc