Hyaluronic acid gel, a method of its production and medical material containing it
AssigneeDenki Kagaku Kogyo Kabushiki Kaisha
InventorsYoshiaki Miyata, Akio Okamoto, Masatoshi Kawata, Kazuhiro Oshima, Masamichi Hashimoto, Kazuhiko Arai, Tomio Sawada
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Abstract
A gel made of hyaluronic acid alone which is hardly soluble in a neutral aqueous solution and which keeps its shape for at least one day in a neutral aqueous solution at 25° C.
Claims10
A gel comprising hyaluronic acid, or its alkali metal salt, said gel prepared by at least once freezing and subsequently thawing a hyaluronic acid aqueous solution at a pH of 3.5 or below, which has not been subjected to chemical crosslinking by a chemical crosslinking compound other than hyaluronic acid or chemical modification by a chemical modifying compound other than hyaluronic acid, and which is not in the form of a complex with a cationic polymer and (1) which dissolves in a neutral aqueous solution at 25° C. in one day to a degree of dissolution of at most 50%, or (2) which dissolves in a neutral aqueous solution at 37° C. in 12 hours to a degree of dissolution of at most 50%, or both (1) and (2).
A biomedical material containing a gel made of hyaluronic acid or its alkali metal salt, said gel prepared by at least once freezing and subsequently thawing a hyaluronic acid aqueous solution at a pH of 3.5 or below, wherein said gel has not been subjected to chemical crosslinking by a chemical crosslinking compound other than hyaluronic acid or chemical modification by a chemical modifying compound other than hyaluronic acid, and which is not in the form of a complex with a cationic polymer which satisfies the following requirements (a) and (b):
- (a) the hyaluronic acid gel dissolves in a neutral aqueous solution at 25° C. in one day to a degree of dissolution of at most 50%, and
- (b) the gel is obtained by acid hydrolysis of hyaluronic acid under conditions such that said hyaluronic acid gel dissolves to yield solubilized hyaluronic acid having a branched structure and containing a molecular weight fraction with a branching degree of at least 0.5.
A biomedical material containing a hyaluronic acid, or its alkali metal salt, gel and an un-gelled hyaluronic acid, said gel prepared by at least once freezing and subsequently thawing a hyaluronic acid aqueous solution at a pH of 3.5 or below and wherein said gel has not been subjected to chemical cross-linking by a chemical cross-linking compound other than hyaluronic acid or chemical modification by a chemical modifying compound other than hyaluronic acid, and said gel is not in the form of a complex with a cationic polymer, wherein the hyaluronic acid gel dissolves in a neutral aqueous solution at most 50%, and the hyaluronic acid gel is obtained by acid hydrolysis of hyaluronic acid under conditions such that said hyaluronic acid gel dissolves to yield solubilized hyaluronic acid having a branched structure and containing a molecular weight fraction with a branching degree of at least 0.5.
A biomedical material containing, in the form of a sheet, a film, a flake, a sponge, a mass, a fiber or a tube, (1) hyaluronic acid gel made of hyaluronic acid, or its alkali metal salt, said gel prepared by at least once freezing and subsequently thawing a hyaluronic acid aqueous solution at a pH of 3.5 or below, and wherein said gel has not been subjected to chemical crosslinking or chemical modification by a compound other than hyaluronic acid, and which is not in the form of a complex with a cationic polymer and (2) an un-gelled hyaluronic acid.
Dependencies are inferred from the claim text.