Transdermal Microneedle Device with Bilateral Force Biasing
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Solution Overview
Problem
Existing transdermal drug delivery devices using microneedle assemblies often fail to consistently deliver drugs beneath the stratum corneum layer of the skin, as the small size of the needles can lead to incomplete penetration and drug absorption issues due to inconsistent force application and skin elasticity, resulting in incomplete drug absorption.
Innovation Solution
A transdermal drug delivery device with a housing that includes a microneedle assembly and a reservoir, where a pushing element applies a continuous bilateral force with both downward and upward components to ensure consistent penetration and retention of microneedles within the skin, enhancing drug delivery by maintaining microneedle insertion and facilitating capillary flow of the drug formulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If microneedle assemblies are used for transdermal drug delivery, then patient pain is reduced and constant drug rate delivery is enabled, but inconsistent needle penetration depth occurs due to small needle size and skin elasticity
Solution Approach 1:
The patent applies the counterweight principle by using a biasing element (spring) that exerts a continuous upward force on the microneedle assembly to counteract the downward elastic recoil of the skin after insertion. This maintains consistent penetration depth despite the small needle size, resolving the contradiction between reduced patient pain and reliable penetration depth.
2Duration of action of moving object
If microneedle assemblies are used for transdermal drug delivery, then constant drug rate delivery is enabled, but drug delivery consistency deteriorates due to incomplete penetration beneath stratum corneum
Solution Approach 1:
The biasing element provides continuous upward force to maintain microneedle insertion depth beneath the stratum corneum, ensuring consistent drug delivery. This resolves the contradiction between extended drug delivery duration and reliable delivery consistency by preventing needle retraction.
Solution Approach 2:
The device pre-loads the biasing element in a compressed state before use, storing elastic potential energy that is immediately released upon application to the skin. This preliminary action ensures consistent penetration force is applied from the moment of insertion, improving both delivery duration and consistency.
3Object-affected harmful factors
If small microneedles are used, then patient pain is reduced, but force application consistency deteriorates leading to incomplete skin penetration
Solution Approach 1:
The spring biasing element provides continuous upward force to compensate for inconsistent downward force application. This resolves the contradiction by maintaining force consistency without requiring larger needles, thus preserving patient comfort while improving penetration reliability.
Solution Approach 2:
The biasing element acts as a mechanical feedback mechanism that continuously adjusts the microneedle insertion depth by exerting upward force in response to skin elastic recoil. This feedback loop maintains consistent penetration depth despite variations in initial force application, resolving the contradiction between small needle size and force consistency.
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 effectively delivers a drug formulation into and through the skin, ensuring consistent and improved absorption by maintaining microneedle penetration and applying a continuous force that enhances skin tension around the microneedles, thereby improving bioavailability and steady-state drug concentration.
Implementation Method 1
a pushing element configured to apply a continuous bilateral force through the device. Specifically, in several embodiments, the pushing element may be configured to apply a continuous downward force through the microneedle assembly to push the microneedles of the assembly into the user's skin. Simultaneously, the pushing element may be configured to apply a continuous upward force against the housing that is transmitted through the housing to the user's skin
Implementation Method 2
The lower housing portion may define a bottom surface including skin attachment means for releasably attaching the lower housing portion to skin of a user
Implementation Method 3
the skin may form such a complete juncture with the needle that the drug flows upwardly along the needle towards the point of insertion
Data Source
AI summary
A transdermal drug delivery device is disclosed that may comprise a housing including an upper housing portion and a lower housing portion. The lower housing portion may define a bottom surface including skin attachment means for releasably attaching the lower housing portion to skin of a user. The upper housing portion may at least partially surround a central region of the device. The device may also include a microneedle assembly and a reservoir disposed within the central region. The reservoir may be in fluid communication with the microneedle assembly. Additionally, the device may include a pushing element disposed above the microneedle assembly within the central region. The pushing element may be configured to provide a continuous bilateral force having a downward component transmitted through the microneedle assembly and an upward component transmitted through the skin attachment means.