Microneedle Devices with Anesthetic Coating for Controlled Release
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Solution Overview
Problem
Current methods for transdermal delivery of local anesthetics, such as through microneedle devices, face challenges in achieving predictable and controlled delivery across the stratum corneum, with existing solutions often requiring lengthy application times and potential for non-uniform penetration and toxicity.
Innovation Solution
Development of microneedle devices coated with a combination of lidocaine, prilocaine, and alpha adrenergic agonists, which provide a controlled, immediate, and sustained release of local anesthetics by dissolving in tissue, ensuring a limited and safe dose without prolonged application times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If topical anesthesia cream is applied to achieve sufficient tissue levels of lidocaine and prilocaine, then the anesthetic effect is achieved, but the application time must be extended to 60 minutes or more
Solution Approach 1:
The invention segments the anesthetic delivery system into microneedles with separate reservoirs for lidocaine and prilocaine, allowing controlled release through microchannels. This segmentation enables rapid delivery of therapeutic levels without requiring prolonged application time, resolving the contradiction between achieving sufficient tissue concentration and minimizing application duration.
Solution Approach 2:
The invention uses a foam carrier system that utilizes gas bubbles to transport and deliver the local anesthetics through the skin. The foam structure provides high surface area and rapid penetration, enabling quick achievement of therapeutic tissue levels without extended application time, thereby resolving the time-concentration contradiction.
2Quantity of substance
If mechanical penetration of the stratum corneum is used to enhance agent delivery, then the amount of agent delivered is increased, but the penetration becomes non-uniform due to skin deflection and resistance
Solution Approach 1:
The invention replaces the mechanical piercing approach with a foam-based delivery system that uses gas bubble expansion and surface tension forces to penetrate and deliver anesthetics. This substitution eliminates the skin deflection and resistance problems associated with mechanical microneedles, providing both enhanced delivery and uniform penetration.
Solution Approach 2:
The invention changes the physical state and delivery parameters by using a foam carrier system with controlled gas bubble sizes and distribution. This parameter change allows the anesthetic to be delivered in a controlled manner through the stratum corneum, achieving both high delivery quantity and uniform distribution without the variability of mechanical penetration.
3Ease of manufacture
If a coating on piercing elements is used to deliver agent, then the device is simpler, but the coating is wiped from the element during penetration and fails to be deposited beneath the stratum corneum
Solution Approach 1:
The invention uses a foam carrier system where gas bubbles carry the anesthetic through the skin rather than relying on a coating that gets wiped off. The foam structure maintains the anesthetic in contact with the skin surface during penetration, ensuring reliable deposition beneath the stratum corneum while keeping the device simple in design.
Solution Approach 2:
The invention creates a composite foam structure combining the local anesthetics with a foam carrier material. This composite approach allows the anesthetic to be delivered within the foam matrix rather than as a surface coating, preventing wipe-off during application while maintaining manufacturing simplicity and ensuring reliable sub-epidermal deposition.
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 microneedle devices achieve higher and extended tissue levels of lidocaine and prilocaine compared to traditional methods, offering a controlled and sustained anesthetic effect while minimizing the risk of toxicity and application time.
Implementation Method 1
Mechanically penetrating or disrupting the outermost skin layers in order to enhance the amount of agent being transdermally delivered
Implementation Method 2
the local anesthetic in the coating on the microneedles dissolves in the tissue underlying the stratum corneum
Implementation Method 3
lidocaine and/or prilocaine in combination with an alpha adrenergic agonist, can provide higher tissue levels of lidocaine and/or prilocaine for an extended period of time
Data Source
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AI summary
A medical device, comprising: an array of microneedles, and a coating disposed on the microneedles, wherein the coating comprises: a local anesthetic selected from the group consisting of lidocaine, prilocaine, and a combination thereof; and a local anesthetic dose-extending component selected from the group consisting of alpha 1 adrenergic agonists, alpha 2 adrenergic agonists, and a combination thereof; wherein the local anesthetic is present in an amount of at least 1 wt-% based upon total weight of solids in the coating, and wherein the dose-extending component/local anesthetic weight ratio is at least 0.0001; a medical device, comprising an array of dissolvable microneedles, the microneedles comprising: a dissolvable matrix material; at least 1 wt-% of a local anesthetic selected from the group consisting of lidocaine, prilocaine, and a combination thereof; and a local anesthetic dose-extending component selected from the group consisting of alpha 1 adrenergic agonists, alpha 2 adrenergic agonists, and a combination thereof; wherein the dose-extending component/local anesthetic weight ratio is at least 0.0001, and wherein wt-% is based upon total weight of solids in all portions of the dissolvable microneedles which contain the local anesthetic; a method of extending a topically delivered local anesthetic dose in mammalian tissue using the devices; and methods of making the devices are provided.