An injection apparatus comprises a hollow body having a first end at which a hollow needle is or can be located. A bung with a rupture seal membrane is located within the hollow body. A piston is also located within the hollow body. The piston, the hollow body and the bung define a volume containing a liquid medicament. The bung is nearer than the piston to the first end of the hollow body. The rupture seal membrane initially isolates the needle from the medicament. The rupture seal membrane is configured to rupture through fluid pressure alone without the rupture seal membrane contacting the needle,thereby allowing the medicament to be expelled through the needle upon movement of the piston causing the provision of pressure to the medicament. In some embodiments, he piston comprises a protrusion located on the side of the piston which faces the first end of the hollow body, the protrusion shaped so as to extend into an aperture in the bung at the end of medicament expulsion. In other embodiments, the bung comprises at least two oppositely oriented rupture seal membranes, with one configured to rupture under fluid pressure from a first side of the bung and another configured to rupture under fluid pressure from the other side of the bung.La présente invention concerne un appareil d'injection qui comprend un corps creux ayant une première extrémité au niveau de laquelle est située ou peut être située une aiguille creuse. Un bouchon comprenant une membrane d'étanchéité de rupture est situé à l'intérieur du corps creux. Un piston est également situé à l'intérieur du corps creux. Le piston, le corps creux et le bouchon délimitent un volume contenant un médicament liquide. Le bouchon est plus proche de la première extrémité du corps creux que le piston. La membrane d'étanchéité de rupture isole initialement l'aiguille du médicament. Seule la membrane d'étanchéité de rupture est conçue pour se rompre sous une pression de fluide sans que la membrane d'étanchéité de rupture
