Patent ID: 8361027
Filing Date: 2013-01-29
Classification: A61K,A61M,Y10S,Y10T

Abstract:
1. A drug delivery device comprising: (a) a housing containing a drug reservoir; (b) a slidable piston operable to expel drug from the drug reservoir; (c) a mechanism in communication with the piston, the mechanism being operable to undergo incremental advancement and thereby drive the drug from the reservoir in a series of fixed increments, wherein the mechanism comprises a rigid ratchet element having regularly spaced formations on a surface thereof; (d) a member operatively associated with the mechanism to cause the incremental advancement of the mechanism as the member moves in a first direction; (e) a pawl carried on the member, the pawl being adapted to make ratcheting engagement with the formations on the rigid ratchet element, wherein the pawl is resiliently biased against the formations on the rigid ratchet element, and wherein the pawl comprises three or more pawl members resiliently biased against the rigid ratchet element at regular intervals along the length of the rigid ratchet element, the pawl members forming pairs, the axial distance between each successive pair of pawl members being different to the axial distance between successive formations; and (f) a gas generator located within the housing and operable to generate gas to expand a chamber, the member being in transmission relation to the chamber, whereby the member is driven by the movement of the chamber to advance the mechanism and thereby drive the drug from the reservoir in the series of fixed increments, each of the fixed increments corresponding to a respective advancement of the mechanism.