Devices and methods for delivery of substances within a medicament container

A method of delivering a dose of a composition, comprising:

• actuating a medical injector such that an energy storage member produces a force via a compressed gas within an internal volume of a housing of the medical injector on a container containing a dose of the composition, the force causing the container to move within the housing to cause a needle to extend from the housing, the movement of the container compressing a retraction spring of the medical injector;
• regulating, via a control assembly positioned within the housing, a portion of the force applied directly on an elastomeric member positioned within the container to cause a movement of the elastomeric member within the container to deliver an initial portion of the dose, the medical injector having an absence of a piston coupled to the elastomeric member to cause a movement thereof;
• initiating a venting of the internal volume via a vent opening defined by the housing, the vent opening being sized to maintain the force produced by the compressed gas acting on the container at a magnitude that is greater than a force applied to the container by the retraction spring during a time to deliver a final portion the dose, the force produced by the compressed gas decreasing to a magnitude that is less than the force applied by the retraction spring concurrent with the delivery of the final portion of the dose;
• and
• retracting the needle via a movement of the container within the housing in response to the force applied by the retraction spring.

A method of delivering a dose of a composition, comprising:

• actuating a medical injector such that an energy storage member produces a force via a first portion of compressed gas within a first gas chamber defined by a housing of the medical injector, the force of the first portion of compressed gas acting on a container containing a dose of the composition, the force causing the container to move within the housing to cause a needle to extend from the housing, the movement of the container compressing a retraction spring of the medical injector;
• regulating, via a control assembly positioned within the housing, a flow of a second portion of gas from the first gas chamber into a second gas chamber to act directly on an elastomeric member positioned within the container, the second gas chamber being defined at least in part by the control assembly, the container, and the elastomeric member such that at least a portion of the second gas chamber is within the container, the second portion of gas within the second gas chamber applying a force directly on the elastomeric member to cause a movement of the elastomeric member within the container to deliver an initial portion of the dose;
• initiating a venting of the first gas chamber via a vent opening defined by the housing, the vent opening being sized to maintain the force produced by the first portion of the compressed gas acting on the container at a magnitude that is greater than a force applied to the container by the retraction spring during a time to deliver a final portion the dose, the force produced by the first portion of the compressed gas decreasing to a magnitude that is less than the force applied by the retraction spring concurrent with the delivery of the final portion of the dose;
• and
• retracting the needle via a movement of the container within the housing in response to the force applied by the retraction spring.