Drug Delivery Device Partial Needle Retraction Mechanism
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Solution Overview
Problem
Subcutaneous drug delivery devices face challenges with pressure buildup at the injection site due to limited blood vessels and fluid paths in subcutaneous tissue, leading to resistance, variability in injection time, and patient discomfort.
Innovation Solution
A drug delivery device with a resilient member, such as a spring or elastomeric bumper, is used to partially retract the drug delivery member after insertion, increasing the injection cavity size and reducing tissue resistive pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If subcutaneous injection is used for gradual drug release, then the injection process is automated and simplified for patients, but pressure builds up at the injection site causing resistance, variable injection time, and patient discomfort
Solution Approach 1:
The needle assembly is made dynamically adjustable through a resilient member (spring) that allows the needle to be positioned at different depths. The needle can be partially retracted into the hub after initial insertion, creating a dynamic adjustment capability that resolves the pressure buildup issue while maintaining automated injection functionality
Solution Approach 2:
The injection depth parameter is made variable through the resilient member mechanism. By changing the needle insertion depth from full insertion to partial retraction, the system optimizes the balance between achieving sufficient tissue penetration for drug delivery and minimizing excessive pressure buildup that causes discomfort and variability
2Reliability
If the drug delivery member is fully inserted for adequate tissue penetration, then drug delivery is effective, but tissue resistive pressure increases causing pain and variability
Solution Approach 1:
The system transitions from a static fully-inserted needle position to a dynamic two-position system. The needle is first fully inserted to ensure adequate tissue penetration for reliable drug delivery, then partially retracted using the resilient member to reduce pressure buildup, achieving both effectiveness and comfort
Solution Approach 2:
The needle is initially fully inserted to establish reliable tissue penetration and drug delivery pathway before the resilient member engages to partially retract it. This preliminary full insertion ensures delivery effectiveness is achieved first, then pressure is reduced as a secondary action
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 partial retraction of the drug delivery member reduces tissue resistive pressure, improving the consistency and comfort of the injection process by increasing the injection cavity size.
Implementation Method 1
A resilient member is disposed between the primary container assembly and the outer casing, such that the resilient member is in a deformed state with the drug delivery member in the second position and biases the drug delivery member to move in a retraction direction toward the first position to partially retract the drug delivery member to a retracted position.
Data Source
AI summary
Methods, devices, and components are provided to reduce tissue resistive pressure during a subcutaneous drug delivery operation by increasing the size of the injection cavity by partially retracting the drug delivery member after inserting the drug delivery member to a subcutaneous position. The drug delivery devices described herein include a resilient member that interacts between stationary and moveable components of the drug delivery device. The drug delivery device include drives to move the stationary and moveable components relative to one another to insert a drug delivery member to a subcutaneous depth within a patient and to dispense a drug to the injection cavity in the patient. The resilient member is deformed during the operations or is pre-deformed and the stored energy of the resilient member in the deformed state then acts on the stationary and moveable components to partially retract the drug delivery member to relieve pressure in the injection region.