Laser facilitates week-long sustained transdermal drug delivery at high doses

Author(s): Xinyuan Chen

Traditional patches are most successful in transdermal delivery of low-dose hydrophobic drugs. Week-long transdermal delivery of high-dose hydrophilic drugs remains a big challenge. We recently developed a laser-based powder delivery platform to allow high-dose week-long sustained delivery of hydrophilic drugs across the skin. This platform is based on laser treatment to generate skin microchannels (MCs) followed by topical application of powder drug- coated reservoir patches. Water evaporated from skin MCs gradually dissolve topical drug powder to elicit week-long sustained drug delivery in murine models. Using sulforhodamine b, zidovudine, and bovine serum albumin as model hydrophilic drugs, we found tapped coating could coat 10-20 mg drug per 0.5 cm2 reservoir patch to elicit 3-day sustained delivery, while compression coating could coat ~35-70 mg drug per 0.5 cm2 reservoir patch to elicit week-long sustained delivery. Besides sustained drug delivery, laser-assisted powder reservoir patch delivery also showed a good safety. Laser-generated skin MCs resealed in 1-2 days and completely recovered in 3 days after the week-long sustained delivery. AFL-assisted powder reservoir patch delivery involves no complex powder formulation and only requires incorporation of highly water-soluble mannitol or a similar excipient to elicit the high-efficient delivery. Enlarging reservoir patch size to 10 cm2 can conveniently expands the delivery capacity to gram scale. To our knowledge, this is the first time that high-dose week-long sustained transdermal delivery of hydrophilic drugs was achieved via a simple laser-based powder delivery platform.

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