Patent ID: 8092420

Claim:
An injector device for automatic reconstitution of a substance comprising: a dose-setting mechanism having a cartridge engagement surface extending therefrom, said dose-setting mechanism being adjustable to set a dose for the injector device; a drug cartridge having a distal end with an opening sealed by a pierceable septum and an open proximal end, a first stopper being slidably and sealingly disposed in said drug cartridge between said proximal and distal ends, wherein said drug cartridge has first and second chambers, said first and second chambers being selectively communicatable with each other, a reconstitutable substance being disposed in said second chamber, a diluent suitable for reconstituting said reconstitutable substance being disposed in said first chamber; a housing cooperatively engaging said dose-setting mechanism; and, a biasing means for selectively moving said dose-setting mechanism from a first position to a second position relative to said housing, said cartridge engagement surface moving a predetermined distance relative to said housing with said dose-setting mechanism moving from said first position to said second position, wherein, movement of said dose-setting mechanism from said first position to said second position causes said first stopper to be moved towards said distal end of said drug cartridge under force of movement of said cartridge engagement surface and causes said first and second chambers to communicate with each other, wherein said reconstitutable substance is reconstituted by said diluent, and, wherein, with said dose-setting mechanism moving from said first position to said second position, said drug cartridge being attached to said housing so as to inhibit distal movement of said drug cartridge relative to said housing.