method of manufacturing a tubular capsule comprising fiber having a wall delimiting internal compartments that are isolated from one another , the wall being made from a solution of at least one polymer and the compartments being full of a biologically active medium , the method comprising the steps of : coextruding the solution of at least one polymer and the biologically active medium by simultaneously injecting the polymer solution and the biologically active medium through a die of determined dimensions ; interrupting the injection of the biologically active medium at determined points in time to form in the fiber successive compartments full of the biologically active medium and separated by a solid partition section consisting only of the polymer solution ; immersing the fiber in a coagulation liquid as it leaves the die so as to initiate early coagulation of the polymer solution around the outside of the fiber ; and simultaneously driving the fiber through the coagulation liquid along a determined path .