Capacitance-Based Drug Delivery Member Insertion Depth Sensing
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Solution Overview
Problem
Users of autoinjectors and on-body injectors face challenges in accurately placing the device and activating it, leading to uncertainties about the drug delivery depth and sequence of actions, which can result in incomplete or improper administration.
Innovation Solution
A drug delivery device with a housing, a primary container, and a drug delivery member that moves between retracted and injection positions, utilizing capacitance information monitored by a controller via a wire or optical sensing systems to determine the insertion depth, ensuring accurate drug delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If capacitance sensing is used to measure insertion depth, then measurement precision is improved, but device complexity increases due to additional sensing components and wiring
Solution Approach 1:
The drug delivery member itself serves as the capacitive sensor by utilizing its inherent conductive properties. The member's capacitance changes naturally with insertion depth due to interaction with the patient's body, eliminating the need for separate sensing components. This self-service approach achieves precise depth measurement while avoiding additional complexity from external sensors.
Solution Approach 2:
The drug delivery member performs multiple functions: it delivers the drug and simultaneously serves as the sensing element for depth measurement. By making the delivery member itself conductive and capable of capacitance measurement, the system combines delivery and sensing functions into a single component, reducing overall device complexity while maintaining measurement precision.
2Reliability
If a fixed wire connection is used for capacitance measurement, then reliability is improved by ensuring stable electrical connection, but ease of operation worsens due to constraints on drug delivery member movement
Solution Approach 1:
The electrical connection is divided into two distinct parts: a fixed wire connection at the proximal end for stable signal acquisition, and a flexible distal portion of the drug delivery member that maintains electrical continuity while allowing free movement. This segmentation enables the proximal connection to remain reliable while the distal portion moves independently during insertion and drug delivery operations.
Solution Approach 2:
The drug delivery member incorporates a flexible or movable portion that transitions from a static electrical connection to a dynamic, movement-capable section. This dynamic design allows the member to move freely during insertion while maintaining electrical connection through its inherent flexibility, resolving the conflict between connection stability and operational freedom.
3Measurement precision
If the drug delivery member is made conductive for sensing purposes, then measurement precision is improved, but manufacturing precision requirements increase due to additional conductive material application
Solution Approach 1:
The conductivity of the drug delivery member is adjusted by changing material parameters rather than adding complex conductive structures. By selecting materials with appropriate inherent conductivity or applying simple conductive coatings, the system achieves the necessary capacitance measurement capability without requiring high-precision manufacturing processes for conductive material application.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device provides reliable and accurate depth measurement, enhancing user confidence and ensuring complete and proper drug administration by correlating capacitance or light data with the insertion depth, thus improving the drug delivery process.
Implementation Method 1
The controller is configured to receive from the wire capacitance information associated with the drug delivery member in the injection position
Implementation Method 2
utilizing capacitance information monitored by a controller via a wire or optical sensing systems to determine the insertion depth
Data Source
AI summary
Drug delivery member insertion depth sensing assemblies, drug delivery devices, and methods for determining an insertion depth of a drug delivery member are disclosed. The sensing assemblies can include electrical sensing assemblies with direct or indirect measurement components or optical sensing assemblies with one or more light sources and one or more photodiodes. A controller of the sensing assemblies can receive data associated with the drug delivery member in an insertion position. The data can then be correlated to an insertion depth of the drug delivery member.