Measurements of the gas and particle flow within a converging-diverging nozzle for high speed powdered vaccine and drug delivery

A unique system has been developed based upon the concept of accelerating pharmaceutical agents in particle form with a gas flow to attain sufficient momentum to enter the epidermis of human skin and achieve a pharmacological endpoint. This paper presents an experimental investigation of the transient gas and particle dynamics within a transonic converging-diverging nozzle prototype. The primary gas flow regimes are identified through Pitot-static pressure surveys and schlieren images with a high frame rate. The action of the gas flow-field in imparting momentum to the drug particles is investigated through schlieren imaging and time-resolved Doppler global velocimetry (DGV)

Emerging strategies for the transdermal delivery of peptide and protein drugs

Transdermal delivery has been at the forefront of research addressing the development of non-invasive methods for the systemic administration of peptide and protein therapeutics generated by the biotechnology revolution. Numerous approaches have been suggested for overcoming the skin's formidable barrier function; whereas certain strategies simply act on the drug formulation or transiently increase the skin permeability, others are designed to bypass or even remove the outermost skin layer. This article reviews the technologies currently under investigation, ranging from those in their early-stage of development, such as laser-assisted delivery to others, where feasibility has already been demonstrated, such as microneedle systems, and finally more mature techniques that have already led to commercialisation (e.g., velocity-based technologies). The principles, mechanisms involved, potential applications, limitations and safety considerations are discussed for each approach, and the most advanced devices in each field are described