Fluid product dispensing device

A fluid dispenser device comprising:

• at least one predosed reservoir that is hermetically sealed and that contains a single dose of powder;
• an expulsion channel;
• and a reservoir opening system, each reservoir including a closure layer that is suitable for being pierced and/or torn by said opening system so as to enable the powder that is contained in said reservoir to be expelled through said expulsion channel, wherein said reservoir opening system comprises at least one piercer element that is actuated so as to create at least one opening in said closure layer, forming at least one inlet passage for the flow of gas, and at least one outlet passage for the powder entrained by said flow of gas, and said device includes an inhalation trigger system that creates a flow of gas in said expulsion channel only when a user inhales at or above a predetermined inhalation threshold, each predosed reservoir comprising a base layer including a cavity and the closure layer that is bonded to the base layer so as to seal said cavity hermetically, said closure layer comprising an inner layer that is made of a material that is powder-tight, air-tight, and moisture-tight, and a protective outer layer that is bonded on said inner layer, said outer layer is made of a material that has shape memory and that is substantially elastic, so that if the at least one piercer element of the opening system is actuated, and then returned to its rest position without the powder that is contained in the reservoir having been expelled, the outer layer closes in sealed manner at a flap that is cut out by said at least one piercer element, preventing any powder from escaping from said reservoir towards said expulsion channel;
• and wherein the inner layer for the closure layer seals the cavity.