Core Annular Flow for Subcutaneous Viscous Drug Injection
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Solution Overview
Problem
Existing injection devices struggle to deliver high-viscosity fluids, such as high-concentration protein formulations, due to the high molecular weight and viscosity of these fluids, requiring excessive injection force and being unsuitable for subcutaneous delivery by conventional syringes.
Innovation Solution
The use of core annular flow in injection devices, where a high-viscosity fluid is surrounded by a low-viscosity fluid to reduce the injection force, achieved through compartmentalization and controlled fluid flow to create an annulus of low-viscosity fluid around the high-viscosity fluid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high-concentration protein formulations are delivered by injection, then the volume of fluid to be injected is reduced, but the viscosity of the formulation increases making it unsuitable for conventional injection devices
Solution Approach 1:
The patent changes the physical parameters of the fluid system by introducing a viscosity-reducing agent that chemically or physically modifies the formulation to decrease its viscosity. This allows high-concentration protein formulations to be delivered at lower viscosities suitable for conventional injection devices while maintaining the therapeutic concentration and reducing the volume to be injected.
2Quantity of substance
If the concentration of protein formulation is increased to reduce injection volume, then less fluid needs to be injected, but the injection force required increases beyond what most injection devices can provide
Solution Approach 1:
The patent modifies the rheological parameters of the formulation by adding a viscosity-reducing agent, which decreases the viscosity and consequently reduces the injection force required. This enables the delivery of concentrated protein formulations with acceptable injection forces that can be provided by conventional injection devices.
3Stability of the object's composition
If salt is added to reduce viscosity of high-concentration protein formulations, then the usable concentration range is extended, but the viscosity still exceeds acceptable levels for injection
Solution Approach 1:
The patent introduces a viscosity-reducing agent as an intermediary substance that mediates between the high-concentration protein formulation and the injection device. This agent specifically targets and reduces viscosity without interfering with protein stability or activity, enabling formulations at concentrations greater than 100 mg/ml to be delivered with acceptable injection forces.
Solution Approach 2:
The patent changes the physical parameters of the formulation by introducing a viscosity-reducing agent that chemically or physically modifies the formulation to decrease its viscosity. This allows high-concentration protein formulations to be delivered at lower viscosities suitable for conventional injection devices while maintaining the therapeutic concentration and reducing the volume to be injected.
4Object-affected harmful factors
If smaller needle diameters are used to improve patient comfort, then the injection is less painful, but the injection force required increases due to higher resistance
Solution Approach 1:
The patent changes the viscosity parameter of the formulation by adding a viscosity-reducing agent, which decreases the fluid resistance. This allows the use of smaller needle diameters for patient comfort while maintaining acceptable injection forces, as the reduced viscosity compensates for the increased resistance from smaller needle bore.
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
This method significantly reduces the pressure required for injection, enabling the delivery of high-viscosity fluids like protein formulations with reduced discomfort and stability, suitable for subcutaneous administration.
Implementation Method 1
a low-viscosity fluid which forms an annulus around the highly viscous fluid. This significantly reduces the amount of force required for injection
Implementation Method 2
core annular flow is used to deliver such viscous fluids. Highly viscous fluid is located in the 'core' and is lubricated by a lower viscosity fluid which forms an annulus around the highly viscous fluid
Data Source
AI summary
Core annular flow is used to enable the subcutaneous delivery of a viscous fluid such as a protein therapeutic formulation. The high-viscosity fluid is surrounded by a low-viscosity fluid, and the low-viscosity fluid lubricates the passage of the high-viscosity fluid. This allows the use of protein formulations that have a higher concentration and a higher viscosity at comparatively reduced injection forces and reduced injection times. Several different embodiments of injection devices that provide core annular flow are described herein.