@article{DoegeHoenzkeSchumacheretal.2016,
  author    = {D{\"o}ge, Nadine and H{\"o}nzke, Stefan and Schumacher, Fabian and Balzus, Benjamin and Colombo, Miriam and Hadam, Sabrina and Rancan, Fiorenza and Blume-Peytavi, Ulrike and Sch{\"a}fer-Korting, Monika and Schindler, Anke and R{\"u}hl, Eckart and Skov, Per Stahl and Church, Martin K. and Hedtrich, Sarah and Kleuser, Burkhard and Bodmeier, Roland and Vogt, Annika},
  title     = {Ethyl cellulose nanocarriers and nanocrystals differentially deliver dexamethasone into intact, tape-stripped or sodium lauryl sulfate-exposed ex vivo human skin - assessment by intradermal microdialysis and extraction from the different skin layers},
  series = {Journal of controlled release},
  volume    = {242},
  journal   = {Journal of controlled release},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0168-3659},
  doi       = {10.1016/j.jconrel.2016.07.009},
  pages     = {25 -- 34},
  year      = {2016},
  abstract  = {Understanding penetration not only in intact, but also in lesional skin with impaired skin barrier function is important, in order to explore the surplus value of nanoparticle-based drug delivery for anti-inflammatory dermatotherapy. Herein, short-termex vivo cultures of (i) intact human skin, (ii) skin pretreated with tape-strippings and (iii) skin pre-exposed to sodium lauryl sulfate (SLS) were used to assess the penetration of dexamethasone (Dex). Intradermal microdialysis was utilized for up to 24 h after drug application as commercial cream, nanocrystals or ethyl cellulose nanocarriers applied at the therapeutic concentration of 0.05\%, respectively. In addition, Dex was assessed in culture media and extracts from stratum corneum, epidermis and dermis after 24 h, and the results were compared to those in heat-separated split skin from studies in Franz diffusion cells. Providing fast drug release, nanocrystals significantly accelerated the penetration of Dex. In contrast to the application of cream and ethyl cellulose nanocarriers, Dex was already detectable in eluates after 6 h when applying nanocrystals on intact skin. Disruption of the skin barrier further accelerated and enhanced the penetration. Encapsulation in ethyl cellulose nanocarriers delayed Dex penetration. Interestingly, for all formulations highly increased concentrations in the dialysate were observed in tape-stripped skin, whereas the extent of enhancement was less in SLS-exposed skin. The results were confirmed in tissue extracts and were in line with the predictions made by in vitro release studies and ex vivo Franz diffusion cell experiments. The use of 45 kDa probes further enabled the collection of inflammatory cytokines. However, the estimation of glucocorticoid efficacy by Interleukin (IL)-6 and IL-8 analysis was limited due to the trauma induced by the probe insertion. Ex vivo intradermal microdialysis combined with culture media analysis provides an effective, skin-sparing method for preclinical assessment of novel drug delivery systems at therapeutic doses in models of diseased skin. (C) 2016 Elsevier B.V. All rights reserved.},
  language  = {en}
}
@misc{DoegeSchumacherBalzusetal.2017,
  author    = {D{\"o}ge, Nadine and Schumacher, Fabian and Balzus, Benjamin and Colombo, Miriam and Hadam, Sabrina and Rancan, Fiorenza and Blume-Peytavi, Ulrike and Kleuser, Burkhard and Bodmeier, Roland and Vogt, Annika},
  title     = {Particle- based formulations and controlled skin barrier disruption have a signifi cant impact on the delivery and penetration kinetics of dexamethasone as assessed in an ex vivo microdialysis},
  series = {Journal der Deutschen Dermatologischen Gesellschaft},
  volume    = {15},
  journal   = {Journal der Deutschen Dermatologischen Gesellschaft},
  publisher = {Wiley},
  address   = {Berlin},
  issn      = {1610-0379},
  pages     = {182 -- 182},
  year      = {2017},
  abstract  = {Preclinical assessment of penetration not only in intact, but also in barrier-disrupted skin is important to explore the surplus value of novel drug delivery systems, which can be specifically designed for diseased skin. Here, we characterized physical and chemical barrier disruption protocols for short-term ex vivo skin cultures with regard to structural integrity, physiological and biological parameters. Further, we compared the penetration of dexamethasone (Dex) in different nanoparticle-based formulations in stratum corneum, epidermis and dermis extracts of intact vs. barrier-disrupted skin as well as by dermal microdialysis at 6, 12 and 24 hours after topical application. Dex was quantified by liquid-chromatography - tandem-mass spectrometry (LC-MS/MS). Simultaneously, we investigated the Dex efficacy by interleukin (IL) analysis. Tape-stripping (TS) and 4 hours sodium lauryl sulfate 5 \% (SLS) exposure were identified as highly effective barrier disruption methods assessed by reproducible transepidermal water loss (TEWL) changes and IL-6/8 increase which was more pronounced in SLS-treated skin. The barrier state has also a significant impact on the Dex penetration kinetics: for all formulations, TS highly increased dermal Dex concentration despite the fact that nanocrystals quickly and effectively penetrated both, intact and barrier-disrupted skin reaching significantly higher dermal Dex concentration after 6 hours compared to Dex cream. The surplus value of encapsulation in ethyl cellulose nanocarriers could mostly be observed when applied on intact skin, in general showing a delayed Dex penetration. Estimation of cytokines was limited due to the trauma caused by probe insertion. In summary, ex vivo human skin is a highly interesting short-term preclinical model for the analysis of penetration and efficacy of novel drug delivery systems.},
  language  = {en}
}