Angled Microneedle Array with Open Channels for Transdermal Delivery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current transdermal drug delivery methods face challenges in effectively transporting drug molecules through the stratum corneum due to its barrier properties, with existing microneedle arrays either being painful, inconvenient, or expensive to manufacture, and often failing to maintain drug delivery rates or maintain their position in the skin.
Innovation Solution
A microneedle array design featuring a planar substrate with spaced apertures and microneedles projecting at an angle, having a base portion, a tapered tip, and a channel open along the body portion for fluid communication, which can be made from biocompatible materials and fabricated using relatively inexpensive techniques, allowing for efficient drug delivery while minimizing pain and maintaining microneedle insertion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solid microneedle arrays are kept in the skin after insertion, then the holes in the stratum corneum remain open for drug delivery, but the holes become plugged by the microneedles themselves preventing drug flow
Solution Approach 1:
The microneedle is extracted from the center of the pore after insertion, leaving the pore open and unobstructed for drug delivery. This resolves the contradiction by removing the blocking element (microneedle) from the drug flow path while maintaining the pore opening function.
Solution Approach 2:
The microneedle array is divided into multiple discrete microneedles, each creating its own pore. After insertion, the microneedles are removed while the pores remain open, allowing drug to flow through the segmented pathways without obstruction.
2Strength
If a thick layer of drug formulation is applied to solid microneedles to ensure adequate drug supply, then the drug coating becomes strong enough to prevent chipping, but the microneedle sharpness is reduced making insertion more difficult and painful
Solution Approach 1:
The microneedle is removed from the skin after insertion, taking any potential drug coating issues with it. The drug is then applied separately to the skin surface or through a different mechanism, eliminating the trade-off between coating thickness and needle sharpness.
Solution Approach 2:
The microneedles are pre-formed with sharp tips for painless insertion. After insertion and removal, the drug formulation is applied to the skin surface where it can be absorbed through the created pores without requiring a thick coating on the microneedles themselves.
3Productivity
If conventional hollow microneedles with central bore are used, then drug can be delivered through the bore, but the bore is easily plugged by skin tissue during insertion and diffusion through the bore is slow
Solution Approach 1:
The microneedle is extracted after insertion, leaving an open pore without any physical barrier. This eliminates the plugging problem inherent in central bores, as there is no internal structure for tissue to adhere to and block the passage.
Solution Approach 2:
Instead of a single central bore, the invention creates multiple porous pathways through the stratum corneum. The removed microneedle leaves behind a porous structure that facilitates drug diffusion without the plugging issues of a confined central channel.
4Ease of operation
If microneedle arrays are designed with sharp edges for rubbing against skin, then spreading of lotion is facilitated, but the microstructures cannot be inserted or kept in the skin to form fluid channels
Solution Approach 1:
Instead of rubbing sharp edges against the skin surface, the invention uses sharp tips for piercing insertion. The microneedles are designed to penetrate the stratum corneum perpendicular to the surface, creating fluid channels that would not be possible with surface-level rubbing action.
Solution Approach 2:
The microneedles are designed with sharp tips for preliminary insertion into the skin, creating pores before the drug formulation is applied. This preliminary action of piercing enables subsequent drug delivery through the created channels, combining insertion capability with drug delivery function.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Microneedle array devices are provided for transdermal drug delivery. The device includes a substantially planar substrate having an array of apertures; and a plurality of microneedles projecting at angle from the substrate, the microneedles having a base portion integrally connected to the substrate, a tip end portion distal to the base portion, and body portion therebetween, wherein each microneedle has a channel extending substantially from the base portion through at least a part of the body portion, the channel being open along at least part of the body portion and in fluid communication with at least one of the apertures in the substrate. In one embodiment, each microneedle has a rectangular cross-sectional shape, an untapered base portion, a tapered tip end portion, and a channel which is open to two opposing surfaces of the microneedle and extends through the body portion into the tapered tip portion.