Microneedles Technology: Overcoming barriers to effective vaccination
KAJAL GAJANAN TELGOTE
INSTITUTE OF CHEMICAL TECHNOLOGY
Effective vaccine delivery
Edward Jenner, who discovered the first vaccine (against smallpox), administered the vaccine by scratching it onto the first vaccine recipient’s skin. Vaccination is the most powerful tool to protect people from infectious diseases and is an essential element for pandemic preparation. Currently, the COVID-19 pandemic has increased the need for improving vaccination compliance while several countries still suffer from the big burden of illness due to influenza, HIV/AIDS, infectious disease, serum hepatitis (particularly the rising infectious diseases like Ebola virus, Zika virus, and coronavirus). The transdermal vaccination route using biodegradable microneedles has become a rapidly progressing field of research and applications. Microneedle array patch (MAP) is painless and can provide higher patient compliance. Presymptomatic and clinical trials with an immunizing agent MAP showed improved stability, safety, and immunologic effectivity compared to standard vaccine administration. In the future, microneedles-based immunizations could play a central role in vaccine administration.
Microneedle Technology for effective vaccination
The World Health Organization (WHO) estimates that immunization annually prevents 2–3 million deaths. The 1st study of immunization by MAP was carried out in 2002 and the significant milestones of MAP for vaccination are displayed in Figure 1.
Fig 1: Timeline of studies with MAP for vaccination.
Most standard vaccinations are injected with needles and syringes, however have many limitations like pain, needle-stick injuries, needle reuse, and poor patient compliance. To overcome these limitations of standard vaccination, MAP was introduced. MAP has many advantages as follows:
- It is a painless methodology of delivering activities across the skin.
- It avoids cold-chain storage and provides self-administration flexibility.
- It enables slow unleashing of vaccine antigens
- It provides a long shelf life at room temperature
- It reduces the risk of the biohazardous product.
However, every coin has two side, so do MAPs:
- It possesses dosing inadequacy.
- It has poor stability and sterility.
- It has uncertain manufacturing costs.
- Mass production is always needed.
- Lack of feedback on correct administration.
- Effectivity and safety criteria to meet FDA approval not yet established.
Microneedle vaccines induce a sturdy immune reaction because the size of the needle starts from 50 to 900 µm. and have an efficiency to deliver the vaccine to the epidermis and dermis region. The various types of microneedles for vaccine delivery are as follows:
Apart from vaccine delivery, these microneedles technology is reported to be a wonderful carrier for another strategy for various types of drug delivery through a nail, nasal, ocular and ear are described follow:
- Used in Combination therapy
- Vaccine & Gene delivery systems
- Ocular drug delivery systems
- Diagnostic tools for ECG, EEG Measurement
- Bio- macromolecule delivery
- Drug delivery systems
About the Author: Kajal Telgote is a 1st-year M.Tech Pharmaceutical Biotechnology student of the Institute of Chemical Technology, Mumbai. She aims to study thoroughly about drug delivery. Currently, she is working on ‘oral peptide delivery’. She is very passionate about her research work and gives all the efforts to achieve her goal.