Abstract: The invention has for object a method of selecting a composition comprising crosslinked hyaluronic acid (HA) and a low proportion of soluble hyaluronic acid for use in limiting the risk of appearance of an adverse side effect associated with the administration of a composition comprising crosslinked HA.

Abstract: The present invention relates to a process for preparing a hydrogel, comprising the following steps: a) provision of a polysaccharide or a salt thereof; b) crosslinking of the polysaccharide in the presence of 0.05 to 10 mol %, preferentially 0.1 to 2 mol %, of at least one crosslinking agent, or a salt thereof, per 1 mol of repeat units of the polysaccharide; c) functionalisation of the polysaccharide with at least one silylated molecule of formula Chem. I or a salt thereof; d) sol-gel reaction of at least one part of the Si—OR10 groups and optionally at least one part of the SiOR4 groups of the molecule of formula Chem. I or a salt thereof when they are present.

Abstract: The present invention relates to a crosslinked hyaluronic acid gel which derives from the crosslinking of hyaluronic acid or of a salt thereof in the presence of at least an effective amount of at least one endogenous polyamine as a crosslinking agent, said crosslinking being carried out under conditions favorable to the coupling of said hyaluronic acid and of said endogenous polyamine(s).