A pilot study using a novel pyrotechnically driven prototype applicator for epidermal powder immunization in piglets.

ABSTRACT

Epidermal powder immunization (EPI) is an alternative technique to the classical immunization route using needle and syringe. In this work, we present the results of an in vivo pilot study in piglets using a dried influenza model vaccine which was applied by EPI using a novel pyrotechnically driven applicator. A liquid influenza vaccine (Pandemrix®) was first concentrated by tangential flow filtration and hemagglutinin content was determined by RP-HPLC. The liquid formulation was then transformed into a dry powder by collapse freeze-drying and subsequent cryo-milling. The vaccine powder was attached to a membrane of a novel pyrotechnical applicator using oily adjuvant components. Upon actuation of the applicator, particles were accelerated to high speed as determined by a high-speed camera setup. Piglets were immunized twice using either the novel pyrotechnical applicator or classical intramuscular injection. Blood samples of the animals were collected at various time points and analyzed by enzyme-linked immunosorbent assay. Our pilot study shows that acceleration of a dried vaccine powder to supersonic speed using the pyrotechnical applicator is possible and that the speed and impact of the particles is sufficient to breach the stratum corneum of piglet skin. Importantly, the administration of the dry vaccine powder resulted in measurable anti-H1N1 antibody titres in vivo.