An article containing N-acylchitosan is manufactured by a process comprising the steps of providing a mixture containing chitosan and/or N-acylchitosan, and extruding the mixture to form an N-acylchitosan hydrogel. Alternatively, the process comprising the steps of providing a chitosan and/or N-acylchitosan hydrogel, and extruding the hydrogel. An article with a memorized shape is formed by fixing the N-acylchitosan hydrogel in a desired shape, and at least partially drying the fixed hydrogel. A patient is treated by injecting the N-acylchitosan hydrogel.