Microprojection Array with Amorphous Glassy Coating for Transdermal Delivery
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Solution Overview
Problem
Current transdermal drug delivery methods face limitations due to low skin permeability, particularly through the stratum corneum, leading to insufficient delivery rates and degradation of therapeutic proteins, and existing devices like scarifiers struggle with adhesion and uniform penetration, resulting in inconsistent dosages and limited therapeutic effectiveness.
Innovation Solution
A microprojection array with stratum corneum-piercing microprojections coated with a biocompatible, amorphous glassy coating containing a beneficial agent, which adheres well and releases the agent upon hydration, ensuring effective delivery without significant bleeding or coating dislodgment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If passive diffusion is used for transdermal delivery, then the skin is not subjected to painful injection, but the delivery rate is insufficient due to low stratum corneum permeability
Solution Approach 1:
The device segments the stratum corneum barrier by using multiple microprojections to create discrete microchannels, allowing drug delivery while avoiding the need for painful needle injections. This segmentation approach enables sufficient delivery rate through collective action of many small channels.
Solution Approach 2:
The patent introduces microprojections as an intermediary mechanism between the drug reservoir and skin tissue. These microprojections facilitate drug transport through the stratum corneum by creating temporary microchannels, serving as a mediator that overcomes the permeability barrier without requiring high-dose injections.
2Productivity
If the stratum corneum is penetrated to enhance delivery, then transdermal flux increases, but the skin's self-healing process causes punctures to close, limiting agent passage
Solution Approach 1:
The device maintains continuous drug delivery by having the microprojections remain embedded in the skin for an extended period. The reservoir continuously supplies drug through the microchannels, ensuring uninterrupted delivery despite the skin's attempt to heal and close the punctures.
Solution Approach 2:
The microprojections are pre-loaded with drug reservoirs before insertion. This preliminary preparation ensures that the drug delivery system is ready to maintain continuous flux immediately upon insertion, overcoming the skin's natural healing response before it can significantly close the channels.
3Productivity
If liquid coating is applied to microprojections, then the beneficial agent can be delivered, but the coating is dislodged during skin piercing, resulting in inconsistent dosages
Solution Approach 1:
The patent changes the physical state of the coating from liquid to solid by allowing it to dry or cure on the microprojections. This parameter change (from liquid to solid) prevents the coating from dislodging during insertion while still allowing controlled release of the beneficial agent at the target site.
Solution Approach 2:
The device uses a composite structure combining the microprojection material with a solidified coating material. This composite approach ensures the coating adheres firmly to the microprojections during insertion while maintaining the ability to release the beneficial agent at the destination, achieving both delivery effectiveness and dosage consistency.
4Object-affected harmful factors
If microprojections pierce to shallow depth, then bleeding is avoided, but the stratum corneum barrier remains intact, limiting agent delivery
Solution Approach 1:
The microprojections are designed with specific dimensional parameters (length, diameter, tip geometry) that enable them to locally penetrate the stratum corneum barrier to a controlled shallow depth. This local quality optimization allows sufficient drug delivery through the barrier while avoiding deeper tissue damage and bleeding.
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 microprojection array achieves efficient and consistent delivery of biologically active agents by piercing the stratum corneum, releasing the agent into the skin tissue, enhancing transdermal flux and maintaining therapeutic effectiveness while minimizing adverse interactions and coating loss.
Implementation Method 1
The coating preferably has sufficient water solubility such that when the microprojections are disposed within the patient's tissue the coating is easily and quickly dissolved, thereby releasing the beneficial agent
Implementation Method 2
the coating is easily and quickly dissolved, thereby releasing the beneficial agent
Implementation Method 3
Passive transdermal drug delivery systems generally rely on passive diffusion to administer the drug
Data Source
AI summary
The device including a plurality of stratum corneum-piercing microprojections, and a solid coating disposed upon the microprojections, wherein the solid coating includes at least one beneficial agent and a biocompatible carrier is provided. The device is applied to the skin of a living animal (e.g., a human), causing the microprojections to pierce the stratum corneum and deliver an effective dose of the agent to the animal.