Polymeric Microneedle Systems for Transdermal and Intradermal Drug Delivery

Microneedles arrays are minimally-invasive systems that painlessly, and without drawing blood, penetrate the skin's stratum corneum barrier to allow delivery of molecules not normally amenable to administration into or across the skin. The concept was first described in a 1976 patent from the Alza Corporation. When microneedles were finally realised in a 1998 paper from Mark Prausnitz, excitement started to build in the scientific community. Since then, numerous studies have suggested that microneedles would have the ability to deliver vaccines without use of a conventional needle, meaning skilled healthcare workers would not be required - This would be particularly important in developing countries. If the microneedles would also dissolve in skin to be self-disabling, then disposal would no longer be an issue. Furthermore, if such a dry state formulation would also exhibit enhanced stability when stored at conditions ambient in sub-Saharan Africa, then vaccination of children in the world's poorest countries would be revolutionised. This led to considerable hype. However, failures by Zosano Pharma and Radius Health, amongst others, served to significantly dampen expectations. However, major recent developments have changed everything. Micron Biomedical, originally a spin-off from the Prausnitz lab at Georgia Tech, have reported excellent Phase 1/2 clinical trial results for vaccination of children as young as 9 months with the measles and rubella vaccine from the Serum Institute of India delivered using Micron's dissolving microneedle system by the Medical Research Council Unit in The Gambia, part of the London School of Hygiene and Tropical Medicine. In November 2023, Micron announced a $23.6 million grant from the Bill & Melinda Gates Foundation that will fund mass production. Separately, Micron announced partnership with LTS Lohmann, the world' ;argest producer of transdermal patches. LTS have Europe's first and only GMP Manufacturing Licence for production of microneedle arrays. Success now seems highly, with eradication of measles in developing countries one particularly important goal. Once this particular microneedle vaccine product has been scaled up and shown to be safe and effective, it is highly likley that investment from the pahrmaceutical industry will follow and microneedle systems will at last be able to fulfill their potential, nit only for vaccines, but also for an array of small and large molecules where delivery across or into the skin would benefit patients. This will undoubtedly grow the trasdermal market, rasing revenue for industry, but also enhancing patient care, while reducing costs for healthcare providers that will no longer need to allocate staff time to administer routine injections.