Micropatches are small devices, often resembling an adhesive bandage, that contain arrays of microscopic needles. These needles, ranging from 25 to 2000 micrometers in height, are designed to deliver substances into the body or extract fluids for diagnostic purposes without the pain of traditional injections.
How Micropatches Deliver
Micropatches function by using microneedles that penetrate the outermost skin layer, the stratum corneum. This layer acts as a barrier, preventing substances from entering the body. The microneedles create tiny channels through this barrier, allowing active compounds to reach deeper skin layers.
Once the microneedles pierce the skin, active compounds are released or absorbed. Some patches use dissolvable microneedles, which dissolve upon contact with the skin’s interstitial fluid, releasing their contents. Other types include hollow microneedles that deliver drugs from a reservoir or solid microneedles that create micro-incisions, followed by a separate drug patch application. The drug then travels through these microscopic tunnels to the dermis, where it can enter the bloodstream through capillaries.
Common Applications
Micropatches are being explored for a wide range of applications, particularly in drug and vaccine delivery. They offer a way to administer various medications, including large molecules like proteins and hormones that are difficult to deliver through the skin. For instance, research has shown their potential for transdermal insulin delivery.
Micropatches are also a promising platform for vaccine administration. They can deliver vaccines directly to the skin, targeting immune cells abundant in the epidermis and dermis. This direct targeting can elicit a strong immune response. Researchers are investigating their use for various vaccines, including influenza and COVID-19 vaccine candidates, with some systems progressing to clinical trials.
Advantages Over Traditional Methods
Micropatches offer several benefits compared to conventional methods like injections or oral medications. A primary advantage is the reduction or elimination of pain, making them a more comfortable option. This pain-free delivery also improves patient adherence to treatment regimens, as it removes a common barrier to medication compliance.
Micropatches enable easier self-administration, allowing patients to apply their own medication or vaccine without requiring trained medical personnel. This can reduce the need for clinic visits and increase accessibility to treatments. They can also enhance drug stability, as some formulations allow for medications to be stored in a dried form, potentially eliminating the need for refrigeration. This simplifies distribution and storage, especially in areas with limited access to cold chain facilities. Finally, because the microneedles are tiny and often dissolve or are self-disabling, they generate less biohazardous waste compared to conventional hypodermic needles.