Comparing the effects of three different multilayer dressings for pressure ulcer prevention on sacral skin after prolonged loading: An exploratory crossover trial.

Evidence suggests that preventive dressings applied on sacral skin help to prevent pressure ulcers. However, possible performance differences of different dressing types are unclear. An exploratory randomized crossover trial with intra-individual comparisons was conducted to compare the effects of three different multi-layer foam dressings (Mepilex Border Sacrum, ALLEVYN Life Sacrum and Optifoam Gentle Sacrum) compared to no dressing on the sacral skin. Healthy female volunteers (n = 12, mean age 72 years) wore three different dressings on their sacral skin for 3.5 hours while lying supine on a standard hospital mattress. At regular intervals, subjects performed standardized movements to enhance shear loads. Skin surface temperature, stratum corneum hydration, erythema, skin roughness and the interleukin 1 alpha (IL-1α) concentration per total protein were measured at baseline and after the lying periods. After 3.5 hours, the median skin temperature increased in all four groups between 3.0°C and 3.8°C with only minor differences between the no dressing and the dressing groups. Median stratum corneum hydration increased during the lying period in all groups with highest increases in the Optifoam Gentle Sacrum (7.3 arbitrary units) and no dressing group (7.0 arbitrary units). There was a median decrease of the mean roughness (Rz) in the Optifoam Gentle Sacrum group of -6.3 µm but no relevant changes in the other groups. After loading, the erythema index was highest in the ALLEVYN Life Sacrum and no dressing groups. Highest releases of IL-1α were observed in the ALLEVYN Life Sacrum and Optifoam Gentle Sacrum groups, in the Mepilex Border Sacrum group changes were minor. Study results indicate, that the application of preventive dressings on sacral skin during loading do not cause additional occlusion compared to loading without dressings when lying supine. Different dressings cause different cutaneous responses during loading.

Physiological and Molecular Effects of in vivo and ex vivo Mild Skin Barrier Disruption.

The success of topically applied treatments on skin relies on the efficacy of skin penetration. In order to increase particle or product penetration, mild skin barrier disruption methods can be used. We previously described cyanoacrylate skin surface stripping as an efficient method to open hair follicles, enhance particle penetration, and activate Langerhans cells. We conducted ex vivo and in vivo measurements on human skin to characterize the biological effect and quantify barrier disruption-related inflammation on a molecular level. Despite the known immunostimulatory effects, this barrier disruption and hair follicle opening method was well accepted and did not result in lasting changes of skin physiological parameters, cytokine production, or clinical side effects. Only in ex vivo human skin did we find a discrete increase in IP-10, TGF-ß, IL-8, and GM-CSF mRNA. The data underline the safety profile of this method and demonstrate that the procedure per se does not cause substantial inflammation or skin damage, which is also of interest when applied to non-invasive sampling of biomarkers in clinical trials.

Infundibular protein and RNA microarray analyses from affected and clinically non-affected scalp in male androgenetic alopecia patients.

Non-invasive sample collection methods could facilitate clinical research on hair diseases. In an exploratory experimental study on six male volunteers with untreated androgenetic alopecia (AGA), Hamilton-Norwood stage IIIv-IV, skin surface and infundibular protein as well as RNA extracts from plucked hair follicles were analyzed from frontal skin, vertex and clinically unaffected occiput. Slightly increased levels of inflammatory markers were only found in AGA-affected scalp skin and infundibulum, not in RNA from plucked hair follicles. RNA expression profiles point towards differential expression of genes involved in hair cycle regulation, hair keratin production, but also RNA methylation and ion channel regulation.

Hair follicle targeting, penetration enhancement and Langerhans cell activation make cyanoacrylate skin surface stripping a promising delivery technique for transcutaneous immunization with large molecules and particle-based vaccines.

Transcutaneous immunization (TCI) requires targeting of a maximum number of skin antigen-presenting cells as non-invasive as possible on small skin areas. In two clinical trials, we introduced cyanoacrylate skin surface stripping (CSSS) as a safe method for TCI. Here, using ex vivo human skin, we demonstrate that one CSSS procedure removed only 30% of stratum corneum, but significantly increased the penetration of 200 nm polystyrene particles deep into vellus and intermediate hair follicles from where they could not been retrieved by conventional tape stripping. Two subsequent CSSS had no striking additional effect. CSSS increased particle penetration in superficial stratum corneum and induced Langerhans cell activation. Formulation in amphiphilic ointment or massage did not substantially influences the interfollicular penetration profiles. Hair follicle (HF) targeting by CSSS could become a highly effective tool for TCI when combined with carrier-based delivery and is gaining new attention as our understanding on the HF immune system increases.

Application of single molecule fluorescence microscopy to characterize the penetration of a large amphiphilic molecule in the stratum corneum of human skin.

We report here on the application of laser-based single molecule total internal reflection fluorescence microscopy (TIRFM) to study the penetration of molecules through the skin. Penetration of topically applied drug molecules is often observed to be limited by the size of the respective drug. However, the molecular mechanisms which govern the penetration of molecules through the outermost layer of the skin are still largely unknown. As a model compound we have chosen a larger amphiphilic molecule (fluorescent dye ATTO-Oxa12) with a molecular weight >700 Da that was applied to excised human skin. ATTO-Oxa12 penetrated through the stratum corneum (SC) into the viable epidermis as revealed by TIRFM of cryosections. Single particle tracking of ATTO-Oxa12 within SC sheets obtained by tape stripping allowed us to gain information on the localization as well as the lateral diffusion dynamics of these molecules. ATTO-Oxa12 appeared to be highly confined in the SC lipid region between (intercellular space) or close to the envelope of the corneocytes. Three main distinct confinement sizes of 52 ± 6, 118 ± 4, and 205 ± 5 nm were determined. We conclude that for this amphiphilic model compound several pathways through the skin exist.

Ciprofloxacin-Loaded Polyvinylpyrrolidone Foils for the Topical Treatment of Wound Infections with Methicillin-Resistant Staphylococcus aureus (MRSA).

Bacterial infections are a constant challenge in the management of acute and chronic wounds. Chronic wounds, such as diabetic foot ulcers, have increased significantly in the last few years due to the rise of an aging population. A better understanding of the infectious pathophysiological mechanisms is urgently needed along with new options for the treatment of wound infections and wound-healing disorders. New advances in the preparation of biocompatible dressing materials that can be loaded with antimicrobial drugs may improve the topical treatment of infected wounds. In this study, we investigated the antimicrobial activity of polyvinylpyrrolidone (PVP) foils loaded with ciprofloxacin (Cipro-foils) in the presence of acetic acid as a co-solvent. We used ex vivo human wounds that were infected with two bacterial strains: methicillin-resistant Staphylococcus aureus (MRSA) or Pseudomonas aeruginosa (PAO1). The effectiveness of the treatment was demonstrated by the quantification of the living bacteria extracted from the wound and the detection of released immunological mediators in skin extracts and in the skin culture media. We found that Cipro-foils effectively treated the infection with both PAO1 and MRSA. Other than PAO1, MRSA had no lytic activity toward skin proteins. MRSA infections increased cytokines' expression and release. Interestingly, treatment with Cipro-foils could partially counteract these effects.

Surface functionalization of silica nanoparticles supports colloidal stability in physiological media and facilitates internalization in cells.

The influence of the surface functionalization of silica particles on their colloidal stability in physiological media is studied and correlated with their uptake in cells. The surface of 55 ± 2 nm diameter silica particles is functionalized by amino acids or amino- or poly(ethylene glycol) (PEG)-terminated alkoxysilanes to adjust the zeta potential from highly negative to positive values in ethanol. A transfer of the particles into water, physiological buffers, and cell culture media reduces the absolute value of the zeta potential and changes the colloidal stability. Particles stabilized by L-arginine, L-lysine, and amino silanes with short alkyl chains are only moderately stable in water and partially in PBS or TRIS buffer, but aggregate in cell culture media. Nonfunctionalized, N-(6-aminohexyl)-3-aminopropyltrimethoxy silane (AHAPS), and PEG-functionalized particles are stable in all media under study. The high colloidal stability of positively charged AHAPS-functionalized particles scales with the ionic strength of the media, indicating a mainly electrostatical stabilization. PEG-functionalized particles show, independently from the ionic strength, no or only minor aggregation due to additional steric stabilization. AHAPS stabilized particles are readily taken up by HeLa cells, likely as the positive zeta potential enhances the association with the negatively charged cell membrane. Positively charged particles stabilized by short alkyl chain aminosilanes adsorb on the cell membrane, but are weakly taken up, since aggregation inhibits their transport. Nonfunctionalized particles are barely taken up and PEG-stabilized particles are not taken up at all into HeLa cells, despite their high colloidal stability. The results indicate that a high colloidal stability of nanoparticles combined with an initial charge-driven adsorption on the cell membrane is essential for efficient cellular uptake.

Identification of anti-microbial peptides and traces of microbial DNA in infrainfundibular compartments of human scalp terminal hair follicles.

BACKGROUND: The upper follicular compartment, a well-known reservoir of cutaneous microbiota, constitutes a space for intensive cross-barrier dialogue. The lower follicle comprises the bulb and bulge, structures with relative immune-privileged status, crucial for physiological cycling, and widely considered to be microbial-free. OBJECTIVES: Following our initial immunohistochemical screening for regulatory cytokines and defensin expression in anagen hair follicles, we aimed to confirm our results with a follow-up ELISA investigation. We postulated that exposure to microbial components may trigger expression, and thus opted to investigate microbial presence in this area. MATERIALS & METHODS: We performed immunohistochemical staining for selected cytokines and antimicrobial peptides, and Gram and Giemsa staining on tissue sections from healthy individuals. Based on ELISA analyses, we confirmed a marked presence of IL-17A- and HBD2 in infrainfundibular compartments from plucked anagen hair follicles of 12 individuals (six females, six males; frontal and occipital scalp sites). 16S rRNA sequencing on microbial DNA extracted from lower follicles, as well as fluorescence in situ hybridization (FISH) were applied to explore bacterial presence in the infrainfundibular compartments. RESULTS: 16S rRNA sequencing yielded reproducible data of bacterial presence in infrainfundibular compartments of plucked scalp follicles; Lawsonella clevelandensis, Staphylococcaceae and Propionibacteriaceae were the most abundant bacteria. Also, FISH revealed biofilm structures formed by Cutibacterium acnes (formerly Propionibacterium acnes) and Staphylococcus sp. below the infundibulum. CONCLUSION: As the skin microbiome largely influences the local immune system, the presence of bacteria in proximity to follicular immune-privileged areas may be of relevance to hair cycling in health and disease.

Topical Delivery of Rapamycin by Means of Microenvironment-Sensitive Core-Multi-Shell Nanocarriers: Assessment of Anti-Inflammatory Activity in an ex vivo Skin/T Cell Co-Culture Model.

INTRODUCTION: Rapamycin (Rapa) is an immunosuppressive macrolide that inhibits the mechanistic target of rapamycin (mTOR) activity. Thanks to its anti-proliferative effects towards different cell types, including keratinocytes and T cells, Rapa shows promise in the treatment of skin diseases characterized by cell hyperproliferation. However, Rapa skin penetration is limited due to its lipophilic nature (log P = 4.3) and high molecular weight (MW = 914 g/mol). In previous studies, new microenvironment-sensitive core multishell (CMS) nanocarriers capable of sensing the redox state of inflamed skin were developed as more efficient and selective vehicles for macrolide delivery to inflamed skin. METHODS: In this study, we tested such redox-sensitive CMS nanocarriers using an inflammatory skin model based on human skin explants co-cultured with Jurkat T cells. Serine protease (SP) was applied on skin surface to induce skin barrier impairment and oxidative stress, whereas phytohaemagglutinin (PHA), IL-17A, and IL-22 were used to activate Jurkat cells. Activation markers, such as CD45 and CD69, phosphorylated ribosomal protein S6 (pRP-S6), and IL-2 release were monitored in activated T cells, whereas pro-inflammatory cytokines were measured in skin extracts and culture medium. RESULTS: We found that alteration of skin barrier proteins corneodesmosin (CDSN), occludin (Occl), and zonula occludens-1 (ZO-1) as well as oxidation-induced decrease of free thiol groups occurred upon SP-treatment. All Rapa formulations exerted inhibitory effects on T cells after penetration across ex vivo skin. No effects on skin inflammatory markers were detected. The superiority of the oxidative-sensitive CMS nanocarriers over the other formulations was observed with regard to drug delivery as well as downregulation of IL-2 release. CONCLUSION: Overall, our results demonstrate that nanocarriers addressing features of diseased skin are promising approaches to improve the topical delivery of macrolide drugs.

Oxidation-Sensitive Core-Multishell Nanocarriers for the Controlled Delivery of Hydrophobic Drugs.

A synthetic route for oxidation-sensitive core-multishell (osCMS) nanocarriers was established, and their drug loading and release properties were analyzed based on their structural variations. The nanocarriers showed a drug loading of 0.3-3 wt % for the anti-inflammatory drugs rapamycin and dexamethasone and the photosensitizer meso-tetra-hydroxyphenyl-porphyrin (mTHPP). Oxidative processes of the nanocarriers were probed in vitro by hydrogen peroxide, and the degradation products were identified by infrared spectroscopy supported by ab initio calculations, yielding mechanistic details on the chemical changes occurring in redox-sensitive nanocarriers. Oxidation-triggered drug release of the model drug Nile Red measured and assessed by time-dependent fluorescence spectroscopy showed a release of up to 80% within 24 h. The drug delivery capacity of the new osCMS nanocarriers was tested in ex vivo human skin with and without pretreatments to induce local oxidative stress. It was found that the delivery of mTHPP was selectively enhanced in skin under oxidative stress. The number and position of the thioether groups influenced the physicochemical as well as drug delivery properties of the carriers.

Redox-Responsive Nanocarrier for Controlled Release of Drugs in Inflammatory Skin Diseases.

A synthetic route for redox-sensitive and non-sensitive core multi-shell (CMS) carriers with sizes below 20 nm and narrow molecular weight distributions was established. Cyclic voltammetric measurements were conducted characterizing the redox potentials of reduction-sensitive CMS while showcasing its reducibility through glutathione and tris(2-carboxyethyl)-phosphine as a proof of concept. Measurements of reduction-initiated release of the model dye Nile red by time-dependent fluorescence spectroscopy showed a pronounced release for the redox-sensitive CMS nanocarrier (up to 90% within 24 h) while the non-sensitive nanocarriers showed no release in PBS. Penetration experiments using ex vivo human skin showed that the redox-sensitive CMS nanocarrier could deliver higher percentages of the loaded macrocyclic dye meso-tetra (m-hydroxyphenyl) porphyrin (mTHPP) to the skin as compared to the non-sensitive CMS nanocarrier. Encapsulation experiments showed that these CMS nanocarriers can encapsulate dyes or drugs with different molecular weights and hydrophobicity. A drug content of 1 to 6 wt% was achieved for the anti-inflammatory drugs dexamethasone and rapamycin as well as fluorescent dyes such as Nile red and porphyrins. These results show that redox-initiated drug release is a promising strategy to improve the topical drug delivery of macrolide drugs.

Qualitative detection of single submicron and nanoparticles in human skin by scanning transmission x-ray microscopy.

First results on single particle detection in human skin samples by x-ray microscopy are reported. 94+/-6 and 161+/-13 nm gold core particles with silica shells and 298+/-11 nm silica particles coated with a gold shell on ultramicrotome sections of human skin were determined. The particles were applied on fresh intact skin samples, which were sectioned prior to imaging. After screening the sections by conventional microscopy techniques, defined areas of interest were qualitatively investigated by scanning transmission x-ray microscopy at the Swiss Light Source. In studies on the percutaneous penetration of 161+/-13 nm particles on human skin samples, x-ray microscopy yielded high-resolution images of single particles spreading on the superficial layer of the stratum corneum and on the epithelium in superficial parts of hair follicles. No deeper penetration was observed. The present work using x-ray microscopy provides the unique opportunity to study qualitative penetration processes and membrane-particle interactions on the level of single particles. This goes beyond present approaches using optical microscopy. Further improvement of this approach will allow one to study particles with different physicochemical properties and surface modifications, including responses of the exposed tissue.

Investigation of polylactic acid (PLA) nanoparticles as drug delivery systems for local dermatotherapy.

PURPOSE: The development of particle-based carriers for transepidermal drug delivery has become a field of major interest in dermatology. In this study, we investigated the suitability of biodegradable poly-lactic acid (PLA) particles loaded with fluorescent dyes as carriers for transepidermal drug delivery. METHODS: The penetration profiles of PLA particles (228 and 365 nm) and the release of dye from the particles were investigated in human skin explants using fluorescence microscopy, confocal laser scanning microscopy and flow cytometry. RESULTS: PLA particles penetrated into 50% of the vellus hair follicles, reaching a maximal depth corresponding to the entry of the sebaceous gland in 12-15% of all observed follicles. The accumulation of particles in the follicular ducts was accompanied by the release of dye to the viable epidermis and its retention in the sebaceous glands for up to 24 h. Kinetic studies in vitro as well as in skin explants revealed, that, although stable in aqueous solution, destabilization of the particles and significant release of incorporated dye occurred upon contact with organic solvents and the skin surface. CONCLUSIONS: These results suggest that particles based on PLA polymers may be ideal carriers for hair follicle and sebaceous gland targeting.

Core-multishell nanocarriers enhance drug penetration and reach keratinocytes and antigen-presenting cells in intact human skin.

In reconstructed skin and diffusion cell studies, core-multishell nanocarriers (CMS-NC) showed great potential for drug delivery across the skin barrier. Herein, we investigated penetration, release of dexamethasone (DXM), in excised full-thickness human skin with special focus on hair follicles (HF). Four hours and 16 h after topical application of clinically relevant dosages of 10 µg DXM/cm2 skin encapsulated in CMS-NC (12 nm diameter, 5.8% loading), presence of DXM in the tissue as assessed by fluorescence microscopy of anti-DXM-stained tissue sections as well as ELISA and HPLC-MS/MS in tissue extracts was enhanced compared to standard LAW-creme but lower compared to DXM aqueous/alcoholic solution. Such enhanced penetration compared to conventional cremes offers high potential for topical therapies, as recurrent applications of corticosteroid solutions face limitations with regard to tolerability and fast drainage. The findings encourage more detailed investigations on where and how the nanocarrier and drug dissociate within the skin and what other factors, e.g. thermodynamic activity, influence the penetration of this formulations. Microscopic studies on the spatial distribution within the skin revealed accumulation in HF and furrows accompanied by limited cellular uptake assessed by flow cytometry (up to 9% of total epidermal cells). FLIM clearly visualized the presence of CMS-NC in the viable epidermis and dermis. When exposed in situ a fraction of up to 25% CD1a+ cells were found within the epidermal CMS-NC+ population compared to approximately 3% CD1a+/CMS-NC+ cells after in vitro exposure in short-term cultures of epidermal cell suspensions. The latter reflects the natural percentage of Langerhans cells (LC) in epidermis suspensions and indicated that CMS-NC were not preferentially internalized by one cell type. The increased CMS-NC+ LC proportion after exposure within the tissue is in accordance with the strategic suprabasal LC-localization. More specifically we postulate that the extensive dendrite meshwork, their position around HF orifices and their capacity to modulate tight junctions facilitated a preferential uptake of CMS-NC by LC within the skin. This newly identified aspect of CMS-NC penetration underlines the potential of CMS-NC for dermatotherapy and encourages further investigations of CMS-NC for the delivery of other molecule classes for which intracellular delivery is even more crucial.

Identification of polystyrene nanoparticle penetration across intact skin barrier as rare event at sites of focal particle aggregations.

The question whether nanoparticles can cross the skin barrier is highly debated. Even in intact skin rare events of deeper penetration have been reported, but technical limitations and possible artifacts require careful interpretation. In this study, horizontal scanning by 2-photon microscopy (2 PM) of full-thickness human skin samples placed in a lateral position yielded highly informative images for skin penetration studies of fluorescently tagged nanoparticles. Scanning of large fields of view allowed for detailed information on interfollicular and follicular penetration in tissue blocks without damaging the sample. Images in histomorphological correlation showed that 2P-excited fluorescence signals of fluorescently tagged 20 and 200 nm polystyrene nanoparticles preferentially accumulated in the stratum corneum (SC) and in the upper part of vellus hair follicles (HFs). Rare events of deeper penetration in the SC and in the infundibulum of vellus HFs were observed at sites of high focal particle aggregations. Wide-field 2 PM allows for imaging of nanoparticle penetration in large tissue blocks, whereas total internal reflection microscopy (TIRFM) enables selective detection of individual nanoparticles as well as clusters of nanoparticles in the SC and within the epidermal layer directly beneath the SC, thus confirming barrier crossing with high sensitivity.

Assessment of skin barrier function and biochemical changes of ex vivo human skin in response to physical and chemical barrier disruption.

Topical dermatotherapy is intended to be used on diseased skin. Novel drug delivery systems even address differences between intact and diseased skin underlining the need for pre-clinical assessment of different states of barrier disruption. Herein, we studied how short-term incubation in culture media compared to incubation in humidified chambers affects human skin barrier function and viability. On both models we assessed different types and intensities of physical and chemical barrier disruption methods with regard to structural integrity, biophysical parameters and cytokine levels. Tissue degeneration and proliferative activity limited the use of tissue cultures to 48h. Viability is better preserved in cultured tissue. Tape-stripping (50×TS) and 4h sodium lauryl sulfate (SLS) pre-treatment were identified as highly reproducible and effective procedures for barrier disruption. Transepidermal water loss (TEWL) values reproducibly increased with the intensity of disruption while sebum content and skin surface pH were of limited value. Interleukin (IL)-6/8 and various chemokines and proteases were increased in tape-stripped skin which was more pronounced in SLS-treated skin tissue extracts. Thus, albeit limited to 48h, cultured full-thickness skin maintained several barrier characteristics and responded to different intensities of barrier disruption. Potentially, these models can be used to assess pre-clinically the efficacy and penetration of anti-inflammatory compounds.

Topically applied virus-like particles containing HIV-1 Pr55gag protein reach skin antigen-presenting cells after mild skin barrier disruption.

Loading of antigen on particles as well as the choice of skin as target organ for vaccination were independently described as effective dose-sparing strategies for vaccination. Combining these two strategies, sufficient antigen recognition may be achievable via the transcutaneous route even with minimal-invasive tools. Here, we investigated the skin penetration and cellular uptake of topically administered virus-like particles (VLPs), composed of the HIV-1 precursor protein Pr55gag, as well as the migratory activity of skin antigen-presenting cells (APCs). We compared VLP administration on ex vivo human skin pre-treated with cyanoacrylate tape stripping (CSSS, minimal-invasive) to administration by skin pricking and intradermal injection (invasive). CSSS as well as pricking treatments resulted in penetration of VLPs in the viable skin layers. Electron microscopy confirmed that at least part of VLPs remained intact during the penetration process. Flow cytometry of epidermal, dermal, and HLA-DR+ APCs harvested from culture media of skin explants cultivated at air-liquid interface revealed that a number of cells had taken-up VLPs. Similar results were found between invasive and minimal-invasive VLP application methods. CSSS pre-treatment was associated with significantly increased levels of IL-1α levels in cell culture media as compared to untreated and pricked skin. Our findings provide first evidence for effective cellular uptake of VLPs after dermal application and indicate that even mild physical barrier disruption, as induced by CSSS, provides stimulatory signals that enable the activation of APCs and uptake of large antigenic material.

40 nm, but not 750 or 1,500 nm, nanoparticles enter epidermal CD1a+ cells after transcutaneous application on human skin.

Although conventional vaccines have generated major successes in the control of infectious diseases, several obstacles remain in their development against chronic diseases (HIV, tuberculosis), against which no current candidate vaccines yet ensure protection. The transcutaneous route of vaccine administration appears to be a promising approach of targeting vaccines toward antigen-presenting cells (APCs) and thus improving immune responses. We investigated the suitability of nanoparticles in this approach. We found a high density of Langerhans cells (LCs) around hair follicles that, when sorted, readily internalized all size particles. However, flow cytometry after transcutaneous application of 40, 750, or 1,500 nm nanoparticles on human skin samples revealed that only 40 nm particles entered epidermal LC. Fluorescence and laser scan microscopies, which were carried out to identify the penetration pathway of transcutaneously applied nanoparticles, revealed that only 40 nm particles deeply penetrate into vellus hair openings and through the follicular epithelium. We conclude that 40 nm nanoparticles, but not 750 or 1,500 nm nanoparticles, may be efficiently used to transcutaneously deliver vaccine compounds via the hair follicle into cutaneous APCs.

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.

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-term ex 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 24h 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 24h, 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 6h 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 45kDa 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.