Enclosed container power supply for a needleless injector

摘要

The power supply is for use with a needleless injector for injecting drug transcutaneously without a needle. The power supply includes an enclosed container that contains a working gas and that can change in volume without an active seal. The enclosed container can include a diaphragm, a bellows, or other structure that has a movable surface. The enclosed container power supply is a component of a needleless injector which has a latch means to hold the power supply in a loaded state and which has an activation means to release the latch and activate the power supply of the needleless injector to initiate drug delivery. The enclosed container power supply of the needleless injector can interface with a drug reservoir means which contains the drug to be delivered and can interface with a reset means to place the power supply in a loaded state. The drug reservoir means can be a disposable ampule or a reusable ampule. The reset means can be a remote reset mechanism or it can be a component of the needleless injector. The power supply can have two or more stages of volume and pressure change during activation. A two-stage power supply can operate with a larger first stage average pressure and a lower second stage average pressure and with a step change in pressure between stages in order to provide enhanced drug delivery to the patient.