In vitro transdermal delivery of therapeutic antibodies using maltose microneedles.

This paper investigates the microneedle-mediated in vitro transdermal delivery of human IgG as a model protein and demonstrates its applicability to deliver a monoclonal antibody. Microchannels created by the treatment of maltose microneedles in full thickness hairless rat skin were visualized using methylene blue staining. Cryostat sections were prepared and stained using hematoxylin and eosin to locate the depth of penetration. In vitro penetration studies were conducted using freshly excised full thickness hairless rat skin and various parameters like needle length, number of needles and effect of donor concentration were examined. Pathway of IgG transport across skin was confirmed by immunohistochemical (IHC) studies. A monoclonal antibody was delivered under optimized conditions. Methylene blue was taken up by microchannels indicating disruption of the stratum corneum and cryosections showed that microneedles just reached the dermis. Human IgG delivery increased with increase in arrays of microneedles, concentration and length of microneedles. IHC studies demonstrated that IgG follows microchannels for transport across the skin. Transdermal delivery was also demonstrated for the monoclonal antibody. In conclusion, maltose microneedles provide a means for the transdermal delivery of macromolecules.