Patent ID: 7749190

Claim:
An automatic injection device containing a pre-loaded charge of medicament for automatically self-administering the medicament upon actuation thereof, the device comprising: a housing; a medicament chamber disposed in the housing, the medicament chamber including a first compartment containing a dry medicament portion, and a second compartment containing a wet medicament portion to be mixed with the dry medicament portion; a plunger rearwardly sealing the second compartment; a seal structure between the first compartment and the second compartment, the seal structure being initially in a sealing condition that maintains the first compartment separate from the second compartment, the seal structure including: at least one flow path formed therein, a forwardly-extending annular wiper portion having a substantially concave-shaped annular surface at a front end of the seal structure positioned to engage inner walls of the first compartment as the seal structure is moved through said first compartment, said wiper portion being configured to direct dry medicament particles engaged with the inner walls radially inward as the seal structure moves through the first compartment, the seal structure being converted to a mixing condition as a result of activation of the device, and a movable sealing plug spaced radially inward from the annular wiper portion, the movable sealing plug having a solid core and moving within the seal structure to convert the seal structure from the sealing condition to the mixing condition, the movable sealing plug maintaining the same orientation with respect to the seal structure as the sealing plug moves to convert the seal structure from the sealing condition to the mixing condition; a needle assembly that dispenses the mixed medicament portions from the medicament chamber; and an activation assembly carried by the housing, operatively connected to the plunger, and including a stored energy source, wherein activation of the activation assembly releases the stored energy from the stored energy source, causing the seal structure to be converted from the sealing condition to the mixing condition, and thereby causing or allowing the medicament portions to be mixed and forced through the needle assembly, the activation also causing the plunger to contact and move the seal structure through the first compartment in the direction of the needle assembly.