CPC A61M 5/2033 (2013.01) [A61M 5/14248 (2013.01); A61M 5/20 (2013.01); A61M 2005/2086 (2013.01); A61M 2205/0266 (2013.01); A61M 2205/364 (2013.01)] | 20 Claims |
1. An auto-injector device comprising:
a medicament reservoir;
a stopper for expelling a medicament out of the medicament reservoir;
a driving element, formed from a shape memory alloy, which has a first configuration and a second configuration and is configured to change shape from the first configuration to the second configuration when a temperature of the driving element is raised above a shape change temperature, so as to drive the stopper through the medicament reservoir; and
a heating mechanism configured to actively heat the driving element, wherein the heating mechanism is a chemical heating element configured to generate heat through an exothermic process, wherein the exothermic process is an exothermic chemical reaction between a first chemical and a second chemical, wherein the heating mechanism comprises:
a first chamber containing the first chemical;
a second chamber containing the second chemical and connected to the first chamber by an aperture;
a frangible membrane arranged across the aperture to separate the first chamber and the second chamber; and
a piercing element configured to be displaced through the first chamber to pierce the membrane to initiate the exothermic chemical reaction.
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