Abstract: A process for the crosslinking of at least one polymer selected from polysaccharides and derivatives thereof, which is carried out in an aqueous solvent by the action of an effective and non-excessive amount of at least one crosslinking agent, characterized in that it is carried out on a mixture containing at least one low-molecular weight polymer and at least one high-molecular weight polymer. A process for the preparation of an injectable monophase hydrogel of at least one crosslinked polymer selected from polysaccharides and derivatives thereof. Crosslinked polymers and injectable monophase hydrogels respectively obtainable by each of said processes.

Abstract: The present invention discloses collagen cross-linked in a micro to non-fibrillar form and at a high concentration. The cross-linked collagen gel has improved volume stability or persistence than collagen cross-linked at a neutral pH. Also disclosed are methods for preparing the inventive cross-linked collagen and using such for augmenting soft tissues in mammals.