A different kind of needle
As a technology class, microarray patches (formerly known as microneedles) include diverse field delivery systems designed to access antigen-presenting and other specialized cells in the top layers of the skin. There are five basic types in development:
- Solid microarray patches used for skin pretreatment, not drug delivery.
- Solid drug-coated microarray patches.
- Polymer microarray patches that release medication when they dissolve.
- Hydrogel microarray patches with an attached reservoir that forms a conduit into the body for drug delivery.
- Hollow microneedles for liquid delivery into the skin.1
All five technologies hold promise for facilitating the safe, effective, and efficient intradermal delivery of vaccines and pharmaceuticals. With possibilities for developing a thermostable microarray patch for self-administration, either by individual patients or in supervised groups, microarray patches also have the potential to increase coverage while reducing programmatic costs, especially for mass immunization campaigns in low-resource settings.
Toward a more optimal delivery scenario
In contrast to conventional injection equipment, microarray patches enable the intradermal administration of vaccines or drugs using needles that are less than one millimeter long. In the case of polymer microarray patches, the sharps component is actually designed to dissolve upon delivery, fully eliminating the risk of needlestick injuries and improper needle reuse.
Additional advantages will likely include minimal and efficient packaging (decreasing the space needed for transport and storage), reduced injection training requirements, and an increased throughput in supervised clinics or campaign settings that are common to developing countries. The use of microarray patches in such settings could be game changing for polio eradication and measles elimination.
The delivery technology may also require less antigen to be effective, which could facilitate increases in the number of doses produced from a given quantity of vaccine.
Building from previous work that included testing of earlier prototypes with herpes simplex virus, malaria, and hepatitis B vaccines, PATH formed a collaboration with the Georgia Institute of Technology and Emory University to create a microarray patch that allows people to self-administer influenza vaccine. With our partners, we continue to evaluate the many opportunities and challenges associated with the technology.
In order to inform further technical development as well as eventual introduction strategies, PATH recently conducted interviews with key opinion leaders representing a variety of areas of expertise in influenza vaccination to gain their insights and perspectives on issues associated with self-administration.2 Additional analyses quantified the cost implications of influenza vaccine delivery with a microneedle patch, particularly if the microneedle device enables self-administration.3 Next steps will involve clinical studies to generate data to demonstrate the product’s safety, feasibility, and acceptability in practice.
We are also researching various drug applications; specifically, the potential of microarray patches to increase safety and facilitate coverage gains by improving the ease and accuracy of pediatric dosing—better enabling, for example, the delivery of antibiotics to newborns.4 In addition, we are evaluating microarray patches for the self-administration of drugs that prevent HIV infection.
- Acceptability of Microarray Patches for Delivery of HIV Pre-exposure Prophylaxis (PrEP) Among Women and Health Care Providers in South Africa [poster]
- Gentamicin for Treatment of Neonatal Sepsis [technical report]
- Microneedle Patches [fact sheet]
- Vaginal Applicator Development for Delivery of Microarray Patches Containing Rilpivirine for HIV Pre-exposure Prophylaxis [poster]
- What Women Want (in HIV protection) [blog post]
1. Kim YC, Park JH, Prausnitz MR. Microneedles for drug and vaccine delivery. Advanced Drug Delivery Reviews. 2012;64(14):1547–1568.
2. Jacoby E, Jarrahian C, Hull HF, Zehrung D. Opportunities and challenges in delivering influenza vaccine by microneedle patch. Vaccine. 2015;33(37):4699–4704.
3. Lee BY, Bartsch SM, Mvundura M, et al. An economic model assessing the value of microneedle patch delivery of the seasonal influenza vaccine. Vaccine. 2015;33(37):4727–4736.
4. González-Vázquez P, Larrañeta E, McCrudden MTC, Jarrahian C, Rein-Weston A, Quintanar-Solares M, Zehrung D, McCarthy H, Courtenay AJ, Donnelly RF. Transdermal delivery of gentamicin using dissolving microneedle arrays for potential treatment of neonatal sepsis. Journal of Controlled Release. 2017 Jul 25. pii: S0168-3659(17)30741-1. doi: 10.1016/j.jconrel.2017.07.032. Available at http://www.sciencedirect.com/science/article/pii/S0168365917307411?via%3Dihub