Method for dynamic filtration of a cross-linked hydrogel

A method for dynamic filtration of a cross-linked biopolymer-based hydrogel comprising the following steps:

• a) transferring a cross-linked biopolymer-based hydrogel, wherein the biopolymer-based hydrogel is cross-linked by means of a chemical cross-linking agent bearing at least two groups that are capable of reacting with one or more functional groups of the biopolymer-based hydrogel, in a dynamic filtration device which is equipped with a process chamber and at least one rotating semipermeable filter disc and diafiltrating the gel comprising the steps of:
• i) concentrating the gel by applying a rotational speed of the at least one rotating semipermeable filter disc within a range of 20 1/min to 500 1/min and an overpressure within a range of 0.5 to 6 bar to a concentration in a range of 10 to 70 mg/g;
• or pumping the gel directly into the process chamber of the dynamic filtration device,
• wherein a first container containing the gel is connected to an inlet of the dynamic filtration device, and
• wherein step (i) further comprises applying pressure to the first container and opening a way from the first container to the inlet of the dynamic filtration device;
• and
• ii) conducting a diafiltration to reduce unwanted molecules selected from unreactive or unbound cross-linking agent molecules and degradation products thereof by applying a rotational speed of the at least one rotating semipermeable filter disc within a range of 20 1/min to 500 1/min and an overpressure within a range of 0.5 to 6 bar,
• wherein the diafiltration involves adding water or a new buffer to a retentate at the same rate as filtrate is being generated,
• wherein a second container containing the water or the new buffer is connected to the inlet of the dynamic filtration device, and
• wherein step (ii) further comprises applying pressure to the second container and opening a way from the second container to the inlet of the dynamic filtration device;
• and
• b) optionally adding a mixture comprising a non-cross-linked polymer and water to the gel.