Variable Dose Drug Delivery Device Limiter Mechanism
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Solution Overview
Problem
Current drug delivery devices lack a flexible mechanism to selectively dispense variable doses of medicaments, particularly for users without medical training, such as diabetic patients, as they often rely on disposable pens with fixed dose settings and lack a resettable dose mechanism.
Innovation Solution
A drug delivery device featuring a medicament reservoir, a drive mechanism, a dose selecting element, a trigger, and a limiter mechanism that allows users to select and dispense specific doses by rotating a dial grip, with a limiter mechanism preventing dose dispensing unless a predefined threshold is met, ensuring accurate and adjustable dosing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a disposable pen delivery device is used with fixed dose settings, then device simplicity and ease of manufacture are improved, but adaptability and versatility are worsened
Solution Approach 1:
The device employs a dynamic dose setting mechanism where the dose selecting element can be rotated to different positions to select variable doses. The limiter mechanism dynamically adjusts to permit or prevent trigger actuation based on the selected dose value, enabling flexible dosing while maintaining a relatively simple device structure.
Solution Approach 2:
The device integrates multiple functions into a single platform: dose selection through rotation, dose verification through the limiter mechanism, and dose dispensing through the trigger. This universal design allows the same device to handle various dose requirements without needing multiple specialized devices.
2Adaptability or versatility
If a resettable dose setting mechanism is added to enable variable dose selection, then adaptability and versatility are improved, but device complexity is worsened
Solution Approach 1:
The limiter mechanism is integrated with the dose selecting element and trigger assembly, combining dose verification and actuation control functions into a unified structure. This merging reduces the need for separate complex components while achieving the desired adaptability.
Solution Approach 2:
The limiter acts as an intermediary mechanism between the dose selecting element and the trigger. It mediates the interaction by permitting or preventing trigger actuation based on the selected dose, thereby adding intelligence and control without requiring complex electronic or mechanical systems.
3Measurement precision
If a limiter mechanism is added to prevent dose dispensing below a threshold, then measurement precision and reliability are improved, but device complexity is worsened
Solution Approach 1:
The limiter mechanism is pre-configured with specific geometric features (protrusions and recesses) that automatically engage at predetermined dose positions. This preliminary design allows the system to enforce dose thresholds without requiring real-time computation or complex control logic during operation.
Solution Approach 2:
The limiter mechanism automatically verifies the selected dose and permits or prevents trigger actuation based on the dose value. The system serves itself by using the mechanical configuration of the limiter and dose selecting element to enforce dosing rules without external intervention or complex monitoring systems.
Data Source
AI summary
A drug delivery device comprises a medicament reservoir attached to a housing, a drive mechanism comprising a plunger movable relative to the housing, a dose selecting element releasably coupled to the drive mechanism and rotatable relative to the housing, a trigger axially movable relative to the housing, and a limiter selectively permitting and preventing axial movement of the trigger depending on the amount of a selected dose. The limiter is constrained to the dose selecting element and to the trigger. One of the limiter or a component part is axially coupled to the housing comprises a track which is in engagement with a blocking feature of the other of the limiter or the component part axially coupled to the housing. The track comprises a narrow section limiting relative movement between the track and the blocking feature and a wide section permitting relative movement between the track and the blocking feature.