Microneedle Devices with Eutectic Anesthetic Coating
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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 resulting in non-uniform penetration and limited duration of anesthetic effect.
Innovation Solution
Microneedle devices coated with a combination of lidocaine and prilocaine, along with a local anesthetic dose-extending component like tetracaine, ropivacaine, or bupivacaine, provide a controlled, immediate, and sustained anesthetic effect by dissolving in tissue, ensuring higher and extended tissue levels compared to traditional methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If microneedles are used to penetrate the stratum corneum, then transdermal delivery is enhanced, but penetration uniformity deteriorates due to skin deflection and resistance
Solution Approach 1:
The patent changes the physical state of the anesthetic from liquid to solid by forming a eutectic mixture, which allows the microneedles to maintain structural integrity during penetration while delivering a controlled amount of anesthetic, thereby improving penetration uniformity while maintaining enhanced agent flux
Solution Approach 2:
The patent uses a composite eutectic mixture of lidocaine and prilocaine in specific proportions (2.5% lidocaine and 2.5% prilocaine) that creates a material with optimized properties for both penetration and controlled delivery, resolving the contradiction between enhanced flux and uniform penetration
2Object-affected harmful factors
If topical anesthesia cream is applied, then pain management is achieved, but application time must be extended to 60 minutes
Solution Approach 1:
The microneedles are pre-coated with the eutectic anesthetic mixture before application, so that the active ingredients are already in position to be delivered immediately upon penetration, eliminating the need for prolonged application time while maintaining effective pain management
Solution Approach 2:
The patent replaces the passive diffusion mechanism of topical creams with active mechanical penetration via microneedles, enabling immediate delivery of the anesthetic without requiring extended contact time, thus reducing loss of time while achieving the same pain relief effect
3Device complexity
If a dried coating on microneedles is used, then device simplicity is improved, but controlled and sustained delivery is compromised
Solution Approach 1:
The patent changes the physical and chemical parameters of the coating by creating a eutectic mixture with specific composition ratios, which controls the dissolution rate and maintains sustained anesthetic effect while keeping the device structure simple and coating-based
Solution Approach 2:
The patent creates local quality variations in the coating by using a eutectic mixture that dissolves at a controlled rate in the tissue, providing sustained delivery of anesthetic while maintaining overall device simplicity, thus resolving the contradiction between simple structure and controlled sustained delivery
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 sustained tissue levels of local anesthetics, offering improved pain management for procedures like venepuncture and dermatological procedures, with a controlled dose that minimizes toxicity risks.
Implementation Method 1
After penetrating the stratum corneum, the local anesthetic in the coating on the microneedles dissolves in the tissue underlying the stratum corneum. In the case of dissolvable microneedles, the local anesthetic in the microneedles dissolves in the tissue.
Implementation Method 2
using topical anesthesia, such as EMLATM cream, a eutectic mixture of 2.5% lidocaine and 2.5% prilocaine
Implementation Method 3
Passive delivery of this type involves the agent diffusing across at least the stratum corneum, where the rate of diffusion through the stratum corneum can be rate limiting.
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 tetracaine, ropivacaine, bupivacaine, procaine 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 local anesthetic and dose-extending component are in a non-eutectic weight ratio; 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 tetracaine, ropivacaine, bupivacaine, procaine and a combination thereof; wherein the local anesthetic and dose-extending component are in a non-eutectic weight ratio, 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.