Angled Injection Nozzle Adapter for Subcutaneous Delivery
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Solution Overview
Problem
Needle-free transdermal injection devices face challenges in ensuring that injectates remain within the subcutaneous layer, as there is a risk of unintended penetration into deeper tissues, leading to reduced treatment efficacy, patient discomfort, and tissue damage.
Innovation Solution
An adapter with an angularly offset nozzle and a cartridge design that includes a skin depressor, allowing the injectate to be delivered at a non-perpendicular angle, ensuring precise subcutaneous layer penetration while maintaining stability and control, with a taper-shaped passageway that controls radial and axial velocities to prevent deeper tissue penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a needle-free injector delivers injectate perpendicular to the skin surface, then the injection mechanism is simple and direct, but there is a risk of unintended penetration into deeper tissues beyond the subcutaneous layer
Solution Approach 1:
The nozzle is angled at a specific angle (e.g., 15-45 degrees) relative to the longitudinal axis of the injector body, creating an asymmetric injection path. This asymmetric geometry allows the injectate to be delivered at a non-perpendicular angle to the skin surface, directing the flow laterally along the subcutaneous layer rather than straight through it, thereby preventing deep tissue penetration while maintaining reliable delivery accuracy
Solution Approach 2:
The injection direction is changed from a single-dimensional perpendicular path to a two-dimensional angled path. By introducing an angular component to the injection vector, the system redirects the injectate flow laterally along the subcutaneous layer, effectively using dimensional change to control penetration depth and prevent harmful deep tissue injection
2Object-affected harmful factors
If the nozzle is angled offset from the longitudinal axis, then deeper tissue penetration is prevented, but the device structure becomes more complex
Solution Approach 1:
The injector is divided into separate functional modules: a main body housing and a detachable adapter assembly containing the angled nozzle. This segmentation allows the complex angled nozzle geometry to be isolated in a separate component that can be easily manufactured, assembled, and replaced, reducing the complexity burden on the main device structure while achieving the desired injection angle control
Solution Approach 2:
An adapter component serves as an intermediary element between the straight bore of the main body and the angled requirement of the nozzle. The adapter contains internal passages that redirect the flow from the longitudinal axis to the angled injection direction, effectively mediating the geometric transformation while keeping the main device structure simple and modular
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 solution increases the likelihood of injectate delivery into the subcutaneous layer, reducing the risk of deeper tissue penetration and maintaining stability during use, allowing for controlled and effective drug delivery.
Implementation Method 1
The passageway has a cross-sectional area, and the taper of the passageway causes the cross-sectional area, as a function of distance along the longitudinal axis in the direction of flow, to decrease in a manner such that a first derivative of the function is negative, continuous, and monotonically increasing, and wherein a second derivative of this function is always positive along the path length. The shape of the taper has a non-zero second derivative over the path length and can be approximately exponential. The first derivative of the shape of the taper has an approximately constant value over a portion of the taper. The taper is shaped to provide a ratio of (1) radial velocity of material at the output of the nozzle to (2) axial velocity of material at the output of the nozzle, which is less than about 0.50.
Data Source
AI summary
An adapter for use with an injection device includes a first end, a second end and a first longitudinal axis extending from the first end and the second end. The adapter also includes a chamber defined by a sidewall between the first end and second end and a nozzle having a passageway extending through the sidewall, the passageway having an input at the chamber, an output at an outer surface of the body and a passageway axis extending from the input to the output, the passageway axis being angularly offset from the longitudinal axis of the channel. A cartridge can include such an adapter.