Cross-linked gels of hyaluronic acid and products containing such gels

{
  "publication_number": "US4636524A",
  "country": "US",
  "kind": "A",
  "title": "Cross-linked gels of hyaluronic acid and products containing such gels",
  "abstract": "Disclosed are cross-linked gels of hyaluronic acid, alone or mixed with other hydrophilic polymers and containing various substances or covalently bonded low molecular weight substances and processes for preparing them. These products are useful in numerous applications including cosmetic formulations and as drug delivery systems.",
  "claims": [
    "1. A delivery system for a substance having biological or pharmacological activity, said system comprising a molecular cage formed of a cross-linked gel of hyaluronic acid or a mixed cross-linked gel of hyaluronic acid and at least one other hydrophilic polymer co-polymerizable therewith and having dispersed therein a substance having biological or pharmacological activity and which is capable of being diffused therefrom in a controlled manner."
  ],
  "description_excerpt": "This application is a division of application Ser. No. 678,895, filed Dec. 6, 1984, now U.S. Pat. No. 4,582,865, issued Apr. 15, 1986.\n\n1. Field of the Invention\n\nThe present invention relates to gels and mixed gels of hyaluronic acid (HA), formulations containing them and methods for preparing them.\n\n2. The Prior Art\n\nHyaluronic acid is a well known, naturally occurring polysaccharide containing alternating N-acetyl-D-glucosamine and D-glucuronic acid monosaccharide units linked with β 1→4 bonds and the disaccharide units linked with β 1→3 glycoside bonds. Hyaluronic acid usually occurs as the sodium salt. The molecular weight of HA is generally within the range of 50,000 up to 8×10 6 and even higher.\n\nThe prior art describes the cross-linking of HA with the use of 1, 2, 3, 4-diepoxybutane in alkaline medium at 50° C. (T. C. Laurent, K. Hellsing, and B. Gelotte, Acta Chem. Scand. 18 [1984], No. 1, 274-5). The product obtained by that method is a gel which substantially swells in water.\n\nIt is also known that divinyl sulfone (DVS) is used for cross-linking polysaccharides, especially cellulose (U.S. Pat. No. 3,357,784).\n\nFIG. 1 is a graphical representation of the experimental data set forth in Example 3 below; and\n\nFIG. 2 is a graphical representation of the experimental data set forth in Example 4 below.\n\nIn one aspect thereof, the present invention provides highly swollen gels of cross-linked hyaluronic acid.\n\nIn another aspect, the invention provides mixed cross-linked gels of hyaluronic acid and other hydrophillic polymers.",
  "cpc": [
    "A61K 8/042",
    "A61K 47/36",
    "A61K 8/73",
    "A61K 8/731",
    "A61K 8/735",
    "A61K 9/0014",
    "A61Q 19/00",
    "C08B 37/0072",
    "C08L 5/08"
  ],
  "ipc": [
    "A61K 47/36",
    "A61K 8/73",
    "A61K 9/00",
    "A61Q 19/00",
    "C08B 37/08",
    "C08F 8/34",
    "C08L 5/08"
  ],
  "assignees": [
    "Biomatrix Inc"
  ],
  "inventors": [
    "Endre A. Balazs",
    "Adolf Leshchiner"
  ],
  "filing_date": "1985-03-08",
  "publication_date": "1987-01-13",
  "grant_date": "1987-01-13",
  "priority_date": "1984-12-06",
  "application_number": "US-70997785-A",
  "family_id": "27102121",
  "cited_by_count": 275,
  "citations": [
    "US3357784A",
    "US4141973A",
    "US4141973B1",
    "US4303676A",
    "US4487865A",
    "US4500676A"
  ]
}