Performance studies of a conical nozzle designed for the macromolecular skin delivery

Human skin is an attractive site for the delivery of protein and peptide-based macromolecular drugs for the treatment of topical and systemic diseases as well as for DNA immunisation. However, the delivery of those macromolecules in or across the skin is undesirably limited due to its permeation property. To expand the number of macromolecules to be delivered to specific targeting tissue/cells, a unique biomedical device, the handheld powdered injection system, has been developed. It is a novel transdermal technology that disposes needles (and syringes), circumvents the need for refrigeration (of vaccines) and has the potential to revolutionise the treatment and prevention of major diseases. To further underwrite device characteristics, in this paper, an advanced computational fluid dynamics technology is utilised to model gas, particle dynamics and gas-particle-target interaction. The statistical analyses show that the microparticles can achieve a mean velocity of 704 m/s representative of intracellular macromolecular deliveries. Knowledge on the gas and particle dynamics can be applied to design effective and efficient handheld powdered delivery systems.