Method of preparing a double chamber container (1; 18; 19) having a distal end side (12; 128; 129), a proximal end side (13; 138; 139) opposite to the distal end side (12; 128; 129), an interior between the distal end side (12; 128; 129) and the proximal end side (13; 138; 139), a distal opening (14; 148; 149) arranged in the distal end side (12; 128; 129) for providing a medium out of the double chamber container (1; 18; 19) and a proximal opening (13; 138; 139) in the proximal end side (13; 138; 139), comprising filling a substance in the interior of the double chamber container (1; 18; 19); inserting a middle plunger (81; 818; 819) in the interior of the double chamber container (1; 18; 19) such that a distal chamber and a proximal chamber are formed, wherein the middle plunger (81; 818; 819) seals the distal chamber from the proximal chamber and wherein the freeze-dried substance is inside the distal chamber; filling a reconstitution medium in the proximal chamber of the double chamber container (1; 18; 19); sealing the proximal opening (13; 138; 139) of the double chamber container (1; 18; 19), providing a holder (2; 28; 29) having a seat (21; 218; 219) arranged to receive the double chamber container (1; 18; 19) in an upright position; and arranging the double chamber container (1; 18; 19) in the seat (21; 218; 219) of the holder (2; 28; 29) such that, in the upright position, the distal end side (12; 128; 129) of the double chamber container (1; 18; 19) extends downwardly and the proximal end side (13; 138; 139) of the double chamber container (1; 18; 19) extends upwardly, characterized by freeze-drying the substance inside the double chamber container (1; 18; 19) while the double chamber container (1; 18; 19) is arranged in a receptacle (71; 718; 719) of a freeze-drying block (7; 78; 79) such that the receptacle (71; 718; 719) of the freeze-drying block (7; 78; 79) encases the distal end side (12; 128; 129) of the double chamber container (1; 18; 19); wherein the double chamber container (1; 18; 19) is arranged in the seat (21; 218; 219) of the holder (2; 28; 29) while the substance is filled in the interior of the double chamber container (1; 18; 19), while the substance is freeze-dried inside the double chamber container (1; 18; 19), while the middle plunger (81; 818; 819) is pushed in the interior of the double chamber container (1; 18; 19), while the reconstitution medium is filled in the proximal chamber of the double chamber container (1; 18; 19), and while the proximal opening (13; 138; 139) of the double chamber container (1; 18; 19) is sealed. filling a substance in the interior of the double chamber container (1; 18; 19); inserting a middle plunger (81; 818; 819) in the interior of the double chamber container (1; 18; 19) such that a distal chamber and a proximal chamber are formed, wherein the middle plunger (81; 818; 819) seals the distal chamber from the proximal chamber and wherein the freeze-dried substance is inside the distal chamber; filling a reconstitution medium in the proximal chamber of the double chamber container (1; 18; 19); sealing the proximal opening (13; 138; 139) of the double chamber container (1; 18; 19), providing a holder (2; 28; 29) having a seat (21; 218; 219) arranged to receive the double chamber container (1; 18; 19) in an upright position; and arranging the double chamber container (1; 18; 19) in the seat (21; 218; 219) of the holder (2; 28; 29) such that, in the upright position, the distal end side (12; 128; 129) of the double chamber container (1; 18; 19) extends downwardly and the proximal end side (13; 138; 139) of the double chamber container (1; 18; 19) extends upwardly, characterized by freeze-drying the substance inside the double chamber container (1; 18; 19) while the double chamber container (1; 18; 19) is arranged in a receptacle (71; 718; 719) of a freeze-drying block (7; 78; 79) such that the receptacle (71; 718; 719) of the freeze-drying block (7; 78; 79) encases the distal end side (12; 128; 129) of the double chamber container (1; 18; 19); wherein the double chamber container (1; 18; 19) is arranged in the seat (21; 218; 219) of the holder (2; 28; 29) while the substance is filled in the interior of the double chamber container (1; 18; 19), while the substance is freeze-dried inside the double chamber container (1; 18; 19), while the middle plunger (81; 818; 819) is pushed in the interior of the double chamber container (1; 18; 19), while the reconstitution medium is filled in the proximal chamber of the double chamber container (1; 18; 19), and while the proximal opening (13; 138; 139) of the double chamber container (1; 18; 19) is sealed.