A method for buffering anesthetic.

A stopper device (1) seals off a medicament container (45) with a stopper element (3), wherein the stopper device is designed to seal the medicament container (45) in an axial direction of a center axis (M) of the medicament container (45), wherein the stopper device (1) is at least partially insertable into the medicament container (45), and the stopper element (3), in the intended installation position in the medicament container (45), is displaceable along the center axis (M) of the medicament container (45). The stopper device (1) has a retention region (23) with at least one retention means (5), wherein a closure element (7), in a first functional state of the stopper device (1), is retained by the retention means (5) in a fixed position relative to the stopper element (3), in particular retained releasably in a retention position on the stopper element (3), in such a way that a cavity (29) is formed between the closure element (7) and the stopper element (3).

A syringe for dispensing medicament from a cartridge, the syringe including a housing having a proximal end, a distal end, and a sidewall defining a passageway adapted to receive the cartridge, an adjustment system comprising an adjustment knob positioned at the proximal end of the housing and two or more adjustment plates extending into the passageway of the housing, and a plunger comprising a plunger rod, the plunger rod extending though a through-hole in the adjustment knob and into the passageway of the housing, wherein rotation of the adjustment knob with respect to the housing causes a distance between the adjustment plates to be changed and a distance between the adjustment plates and an interior of the sidewall of the housing to be changed. The syringe may also include a needle assembly.