The invention provides in one aspect a drug delivery device comprising a drug container (16), and a plunger (18) positioned within the container assembly, the drug container assembly having an outlet for dispensing the drug, wherein, in an initial position, the outlet is sealed a drive mechanism comprising a first stored energy source (42) operable to apply pressure on the plunger or the drug container to pressurise the drug, and a first release mechanism operable to unseal the outlet after the drug has been pressurised. In another aspect, there is provided a drug delivery device comprising a housing, including an external housing portion configured to be held in use and a drug containing portion containing a drug, a needle assembly comprising a needle fixed to a needle hub, the needle hub configured to move relative to the drug containing portion from an initial position within the housing to an insertion position in which the needle extends beyond the housing, a first stored energy source configured to move the needle hub from the initial position to the insertion position, and a plunger within the housing and configured to move relative to the drug containing portion to eject the drug through the needle when the needle is in the insertion position.Linvention concerne, selon un aspect, un dispositif dadministration de médicament comprenant un ensemble récipient de médicament contenant un médicament, et un piston placé dans lensemble récipient, lensemble récipient de médicament comprenant une sortie pour distribuer le médicament, la sortie étant, dans une position initiale, hermétiquement fermée un mécanisme dentraînement comprenant une première source dénergie stockée qui peut servir à appliquer une pression sur le piston ou le récipient de médicament afin de pressuriser le médicament, et un premier mécanisme de libération qui peut servir à ouvrir la sortie après pressurisation du médicament. Dans un autre aspect, linvention concerne un dispositif dadministration
