This work introduces VaxiPatch, a novel vaccination system comprised of subunit glycoprotein vaccine antigens, adjuvants and dermal delivery For this study, rHA of influenza virus B/Colorado/06/2017 was incorporated into synthetic virosomes, and adjuvant liposomes were formed with QS-21 from Saponaria quillaja, with or without the synthetic TLR4 agonist 3D - (6-acyl) PHAD These components were concentrated and co-formulated into trehalose with dye Dermal delivery was achieved using an economical 37-point stainless steel microneedle array, designed for automated fill/finish by microfluidic dispensers used for mass production of immunodiagnostics Vaccine and adjuvant are deposited to form a sugar glass in a pocket on the side of each of the tips, allowing skin penetration to be performed directly by the rigid steel structure In this study, Sprague Dawley rats (n = 6 per group) were vaccinated by VaxiPatches containing 0 3 µg of rHA, 0 5 µg QS-21 and 0 2 µg 3D - (6-acyl) PHAD and dye, resulting in antigen-specific IgG titers 100-fold higher than 4 5 µg of FluBlok (p = 0 001) delivered intramuscularly Similarly, hemagglutination inhibition titers in these animals were 14-fold higher than FluBlok controls (p = 0 01) Non-adjuvanted VaxiPatches were also compared with rHA virosomes injected intramuscularly Accelerated shelf life studies further suggest that formulated virosomal antigens retain activity for at least two months at 60° C Further, co-formulation of a dye could provide a visible verification of delivery based on the temporary pattern on the skin A room-temperature-stable vaccination kit such as VaxiPatch has the potential to increase vaccine use and compliance globally
VaxiPatch™, a novel vaccination system comprised of subunit antigens, adjuvants and microneedle skin delivery: An application to influenza B/Colorado/06/2017