Purpose: Despite many years of research, transdermal delivery has been only successful for low-dose small hydrophobic drugs. We established a novel transdermal delivery platform, called laser-based powder delivery (LPD), for efficient delivery of a wide variety of drugs across the skin in murine models. LPD is based on coating powder drugs onto full-surface of adhesive patches followed by topical application onto laser-generated skin MCs to deliver drugs into the skin
Methods: Highly water-soluble sulforhodamine b (SRB) and ovalbumin (OVA) could be directly coated, while water-insoluble monophosphoryl lipid a (MPL) was first encapsulated into poly(lactic-co-glycolic) nanoparticles (NPs) and then similarly coated for efficient delivery via laser-generated skin MCs. skin MC-based powder delivery (SMPD) was also modified for high-dose drug delivery by coating ‘bulk’ drug powder into reservoir patches. Forty milligrams of SRB/mannitol powder per 0.5 cm2 reservoir patch surface could be coated for efficient delivery via laser-generated skin MCs.
Results: LPD of OVA and haemophilus influenzae type b (Hib) vaccine in the presence of NP(MPL) elicited more than 70-fold higher anti-OVA and anti-Hib antibody titer than SMPD of OVA and Hib vaccine alone.(Fig 1)
Reservoir patch could deliver upto 40 miligrams of powder over a span of three days and can be further scaled up to several hundred milligrams.(Fig 2)
In summary, we developed SMPD for efficient delivery of a wide variety of drugs into the skin. Highly water-soluble drugs can be coated on adhesive patch surface for efficient delivery via laser-generated skin MCs, while water-insoluble drugs can be first encapsulated into PLGA NPs and then similarly coated for efficient delivery via laser-generated skin MCs. SMPD can also be modified for high-dose drug delivery by coating ‘bulk’ drug powder into reservoir patches.LPD showed a good safety since skin MCs were generally resealed in 1-2 days after patch removal. The safe, efficient, and versatile transdermal delivery platform warrants further investigation for clinical use.