Hydrogel precursor formulation and production process thereof

A process for the production of a hydrogel precursor formulation in the form of a powder comprising the steps of:

• providing a first solution A of at least one structural compound, wherein the structural compound is a multi-branched polyethylene glycol (PEG) functionalized with vinyl sulfone;
• providing a second solution B comprising at least one linker compound, wherein the linker compound is a peptide comprising at least two cysteines;
• mixing of the solutions A and B, which results in a precursor solution;
• filling the precursor solution into at least one container;
• and
• lyophilization of the resulting precursor solution,
• wherein a compact powder, which is in the form of a stable cake at the bottom of the at least one container, results from the lyophilization, and wherein the structural compound, and the linker compound are polymerizable by a selective reaction between a nucleophile and a conjugated unsaturated bond or group, and the solutions A and B are mixed under conditions which hinder the selective reaction.