Dose Setting Mechanism With Mechanical Stops for Safe Drug Delivery
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Solution Overview
Problem
Existing drug delivery devices lack precise and safe dose setting mechanisms, particularly for self-administration by non-medically trained individuals, risking inadvertent over- or under-dosage.
Innovation Solution
A drug delivery device with a housing, dose setting member, piston rod, and dosing member featuring a maximum dose stop and zero dose stop mechanism, along with a clutch mechanism, to ensure precise and safe dose setting and delivery, preventing excessive dose setting and providing haptic feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a dose definition mechanism is provided to allow users to set doses, then the device enables self-administration by non-medically trained people, but the risk of inadvertent over- or under-dosage increases
Solution Approach 1:
The patent applies preliminary anti-action by providing a maximum dose stop and zero dose stop that prevent users from setting doses outside the safe range. These mechanical stops create preliminary constraints that counteract the potential for user error before incorrect dosing can occur, allowing non-medically trained individuals to safely self-administer without risking over- or under-dosage.
Solution Approach 2:
The patent implements feedback through haptic feedback mechanisms that provide tactile cues to users during dose setting. The dosing member provides detectable feedback when approaching maximum or zero dose limits, enabling users to sense when they have reached the appropriate dose setting without requiring medical training, thus improving both ease of operation and reliability.
2Productivity
If the dosing member is made rotatable during dose delivery to enable dose delivery, then the set dose can be delivered, but the risk of manipulation during dose delivery increases
Solution Approach 1:
The patent applies dynamics by making the dosing member rotatable during dose delivery while fixed during dose setting. This dynamic behavior allows the dosing member to rotate and deliver the set dose when needed, while maintaining rotational fixation during the setting phase to prevent manipulation. The system transitions between fixed and movable states based on the operational phase, enabling both safe setting and reliable delivery.
3Reliability
If the maximum dose stop engages with the maximum stop feature to limit movement, then the upper dose limit is prevented from being exceeded, but the device complexity increases
Solution Approach 1:
The patent merges the maximum dose stop and zero dose stop functions into the dosing member itself, rather than requiring separate mechanisms. The dosing member integrates multiple functions: dose setting, dose delivery, and dose limiting through its interaction with the maximum stop feature and zero stop feature. This merging approach enforces dose limits reliably while minimizing the increase in device complexity by consolidating functions into existing components.
Data Source
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AI summary
A drug delivery device has a housing with a longitudinal axis, a dose setting member actuatable by a user and rotatable around the longitudinal axis to set a dose to be delivered by the drug delivery device, a piston rod that is configured to be axially advanced in a proximal direction to deliver the set dose, and a dosing member for defining the axial advancement of the piston rod upon delivery of the set dose. The dosing member is axially movable along the longitudinal axis and rotationally movable around the longitudinal axis during dose setting, and the dosing member is rotationally fixed to the dose setting member during dose setting. The dosing member comprises a maximum dose stop that is configured to engage with a maximum stop feature provided at the housing to limit movement of the dosing member with respect to the housing upon setting a maximum dose.