{"id":4430,"date":"2025-04-22T10:10:40","date_gmt":"2025-04-22T08:10:40","guid":{"rendered":"https:\/\/www.ipasum.med.fau.de\/?page_id=4430"},"modified":"2025-05-08T14:08:18","modified_gmt":"2025-05-08T12:08:18","slug":"hautresorption","status":"publish","type":"page","link":"https:\/\/www.ipasum.med.fau.de\/en\/hautresorption\/","title":{"rendered":"Skin resorption"},"content":{"rendered":"<div class=\"rrze-elements accordion style_default\" id=\"accordion-0\">\n<div class=\"accordion-group\">\n<h2 class=\"accordion-heading\"><button class=\"accordion-toggle\" data-toggle=\"collapse\"  href=\"#collapse_0\" aria-expanded=\"false\" aria-controls=\"collapse_0\" id=\"collapse_button_0\"> Barrier function of the skin <\/button><\/h2>\n<div id=\"collapse_0\" class=\"accordion-body\" aria-labelledby=\"collapse_button_0\">\n<div class=\"accordion-inner clearfix\">\n<p>The body surface of an adult man covers about 2 m<sup>2<\/sup>, somewhat less than that of an adult woman. This surface is covered with skin. Specially differentiated cells and components of the skin are responsible for, among other tasks, homeostasis and the perception of pain, temperature, and pressure. Skin forms a barrier that separates us from our environment and protects us from water loss. A substance must first penetrate this skin barrier to reach the blood stream and to be absorbed into the system. The most external skin layer, the stratum corneum, forms the primary part of this barrier. The stratum corneum is composed of 10\u201320 layers of callous, seedless keratinocytes or corneocytes which are embedded to form a lamellar lipid layer in a \u201cbrick-and-mortar\u201d model (Elias 1983). The corneocytes are stabilised against displacement by punctiform, desmosomal compounds (\u201crivets\u201d) and interlocked, hook-shaped surface structures. After the formation of a basal cell layer, keratinocytes travel through the epidermis, become differentiated from corneocytes, and are finally cast off (dandruff).<\/p>\n<p>&nbsp;<\/p>\n<p><a href=\"https:\/\/arbeitsmedizin.cms.rrze.uni-erlangen.de\/files\/2018\/09\/dermale-Penetration_f1.pdf\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-1478 aligncenter\" src=\"https:\/\/arbeitsmedizin.cms.rrze.uni-erlangen.de\/files\/2018\/10\/Dermale-Absorption-300x211.png\" alt=\"\" srcset=\"https:\/\/www.ipasum.med.fau.de\/files\/2018\/10\/Dermale-Absorption-300x211.png 300w, https:\/\/www.ipasum.med.fau.de\/files\/2018\/10\/Dermale-Absorption-768x540.png 768w, https:\/\/www.ipasum.med.fau.de\/files\/2018\/10\/Dermale-Absorption-1024x720.png 1024w, https:\/\/www.ipasum.med.fau.de\/files\/2018\/10\/Dermale-Absorption-213x150.png 213w, https:\/\/www.ipasum.med.fau.de\/files\/2018\/10\/Dermale-Absorption-209x147.png 209w, https:\/\/www.ipasum.med.fau.de\/files\/2018\/10\/Dermale-Absorption-156x110.png 156w, https:\/\/www.ipasum.med.fau.de\/files\/2018\/10\/Dermale-Absorption-284x200.png 284w, https:\/\/www.ipasum.med.fau.de\/files\/2018\/10\/Dermale-Absorption-140x98.png 140w, https:\/\/www.ipasum.med.fau.de\/files\/2018\/10\/Dermale-Absorption-668x470.png 668w, https:\/\/www.ipasum.med.fau.de\/files\/2018\/10\/Dermale-Absorption-145x102.png 145w, https:\/\/www.ipasum.med.fau.de\/files\/2018\/10\/Dermale-Absorption.png 1523w\" \/><\/a><strong>Figure 2: Dermal absorption<\/strong><\/p>\n<p>Chemicals generally pass through the stratum corneum by passive diffusion, whereby speed and amount as well as the physicochemical characteristics of the chemicals and the skin itself (i.e. diffusion area and distance) are factors. The stratum corneum may be crossed by substances intercellularly (see Figure), which means that substances diffuse into the lipid layer along the corneocytes. Depending on the physical and chemical characteristics of a substance, the stratum corneum may be crossed transcellularly, meaning via the corneocytes (see Figure). Potential absorption via hair follicles has also been discussed (see Figure). The transfollicular pathway may be especially relevant for particularly hirsute animal skin.<\/p>\n<p>The absorption of substances in and through the skin into the body can be influenced by many different factors (see Table).<\/p>\n<p>Factors which influence dermal absorption<br \/>\n(per Kilo (2017) <em>Hautabsorption<\/em>. In: Schmitz-Spanke, et al.; <em>Umweltmedizin<\/em>).<\/p>\n<p>&nbsp;<\/p>\n<p>Einflussfaktoren der dermalen Absorption. (nach Kilo (2017) Hautabsorption. In: Schmitz-Spanke et al.; Umweltmedizin)<\/p>\n<table style=\"height: 329px;width: 662px\" width=\"662\">\n<tbody>\n<tr style=\"height: 33px\">\n<td style=\"height: 33px;width: 257.517px\"><\/td>\n<td style=\"height: 33px;width: 400.05px\"><strong>Characteristic<\/strong><\/td>\n<td style=\"height: 33px;width: 697.433px\"><strong>Influencing factor<\/strong><\/td>\n<\/tr>\n<tr style=\"height: 71px\">\n<td style=\"height: 71px;width: 257.517px\">Skin<\/td>\n<td style=\"height: 71px;width: 400.05px\">physiological\/<br \/>\nanatomical\/physical\/<br \/>\nchemical<\/td>\n<td style=\"height: 71px;width: 697.433px\">age \/ condition \/ anatomical location<br \/>\n(metabolic) temperature<br \/>\nhydration of the stratum corneum<\/td>\n<\/tr>\n<tr style=\"height: 71px\">\n<td style=\"height: 71px;width: 257.517px\">Substance<\/td>\n<td style=\"height: 71px;width: 400.05px\">physikalisch\/<br \/>\nchemisch<\/td>\n<td style=\"height: 71px;width: 697.433px\">molecular radius (molekular wight)<br \/>\nwater or lipid solubility (log KOW)<br \/>\ndosage<\/td>\n<\/tr>\n<tr style=\"height: 71px\">\n<td style=\"height: 71px;width: 257.517px\">Solvent<\/td>\n<td style=\"height: 71px;width: 400.05px\">physical\/<br \/>\nchemical<\/td>\n<td style=\"height: 71px;width: 697.433px\">viscosiy<br \/>\ntemperature<br \/>\n\u201epenetration enhancers&#8221;)<\/td>\n<\/tr>\n<tr style=\"height: 52px\">\n<td style=\"height: 52px;width: 257.517px\">Exposure<\/td>\n<td style=\"height: 52px;width: 400.05px\"><\/td>\n<td style=\"height: 52px;width: 697.433px\">area<br \/>\ntime<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/div>\n<div class=\"accordion-group\">\n<h2 class=\"accordion-heading\"><button class=\"accordion-toggle\" data-toggle=\"collapse\"  href=\"#collapse_1\" aria-expanded=\"false\" aria-controls=\"collapse_1\" id=\"collapse_button_1\"> Methods on the experimental measurement of dermal absorption <\/button><\/h2>\n<div id=\"collapse_1\" class=\"accordion-body\" aria-labelledby=\"collapse_button_1\">\n<div class=\"accordion-inner clearfix\">\n<table style=\"height: 215px;width: 77.7844%\" border=\"1\">\n<tbody>\n<tr>\n<td><strong><em>In-vivo <\/em><\/strong>:<\/td>\n<td><em>Measurement in the in-tact organism<br \/>\n<\/em>Studies with test subjects, e.g. intradermal microdialyses, biomonitoring \u2026<\/td>\n<\/tr>\n<tr>\n<td><strong><em>Ex-vivo:<\/em><\/strong><\/td>\n<td>Measurement<em>outside<\/em>of the organism in<em>physiologically and <\/em><em>metabolically in-tact<\/em> systems<br \/>\nStudies on excised skin, e.g. diffusion-cell studies, microdialysis \u2026<\/td>\n<\/tr>\n<tr>\n<td><strong><em>In-vitro<\/em><\/strong><strong>:<\/strong><\/td>\n<td>Measurement in <em>artificial systems<\/em><br \/>\nStudies on artificial cell membranes (e.g. diffusion-cell studies) or in cell cultures \u2026<\/td>\n<\/tr>\n<tr>\n<td><strong><em>In-silico<\/em><\/strong>:<\/td>\n<td><em>Theoretical determinations<\/em> of dermal-absorption mechanisms<br \/>\nCalculations and computer simulations; e.g. according to diffusion principles, experimental datan<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>The gold standard for the evaluation of dermally absorbed substances are <em>in\u2011vivo<\/em> human studies. Since animal skin is considerably distinct from human skin in terms of the thickness of the stratum corneum and the number of hair follicles, it is only partially suitable for penetration studies. Since the skins of various species may also vary with respect to their enzymatic properties\/activity, human studies (<em>in\u00a0vitro<\/em> or <em>ex\u00a0vivo<\/em>) are preferred for the evaluation of substances which are intradermally converted to a pharmacologically (\u201cprodrug\u201d) or toxicologically relevant metabolite (Kilo et al. 2016).<\/p>\n<\/div>\n<\/div>\n<\/div>\n<div class=\"accordion-group\">\n<h2 class=\"accordion-heading\"><button class=\"accordion-toggle\" data-toggle=\"collapse\"  href=\"#collapse_2\" aria-expanded=\"false\" aria-controls=\"collapse_2\" id=\"collapse_button_2\"> Projects <\/button><\/h2>\n<div id=\"collapse_2\" class=\"accordion-body\" aria-labelledby=\"collapse_button_2\">\n<div class=\"accordion-inner clearfix\">\n<div class=\"rrze-elements accordion style_default\" id=\"accordion-1\">\n<div class=\"accordion-group\">\n<h2 class=\"accordion-heading\"><button class=\"accordion-toggle\" data-toggle=\"collapse\"  href=\"#collapse_3\" aria-expanded=\"false\" aria-controls=\"collapse_3\" id=\"collapse_button_3\"> Systemic absorption of organic UV filters from sun-protection products in humans <\/button><\/h2>\n<div id=\"collapse_3\" class=\"accordion-body\" aria-labelledby=\"collapse_button_3\">\n<div class=\"accordion-inner clearfix\">\n<p>Systemic absorption of organic UV\u00a0filters from sun-protection products in humans<\/p>\n<p>funded by the <em>Bayerisches Staatsministerium f\u00fcr Gesundheit und Pflege<\/em><\/p>\n<p>Contact person: <span class=\"fau-person person liste-person\"><span itemscope itemtype=\"http:\/\/schema.org\/Person\"><a href=\"https:\/\/www.ipasum.med.fau.de\/person\/julia-hiller\/\"><span itemprop=\"name\"><span itemprop=\"honorificPrefix\">Dr. med.<\/span> <span class=\"fullname\"><span itemprop=\"givenName\">Julia<\/span> <span itemprop=\"familyName\">Hiller<\/span><\/span><\/span><\/a><\/span><\/span><\/p>\n<p>Sun is important component of everyday life for humans and provides a wide variety of positive effects \u2013 it harbours, however, the risk of short- and long-term damage to the skin via UV\u00a0radiation. Sun-protection products should protect against these harmful rays, such that their use is propagated to all demographic groups to protect against UV\u00a0radiation. Due to the broad usage of light-protection products, the question arises as to potential absorption into the human body.<\/p>\n<p>The primary goal of our research is to estimate exposure with respect to transdermal penetration of the most common sun-protection products used for humans in Germany (ethylhexyl salicylate, octocrylene, and avobenzone). As part of an <em>in\u2011vivo<\/em> study with volunteers, the internal exposure and excretion of these substances and their metabolites were investigated in healthy subjects after proper use of typical sun-protection products under real-world application conditions. The results of the <em>in\u2011vivo<\/em> conditions were compared with those of <em>ex\u2011vivo<\/em> methods using additional diffusion-cell tests, thereby enabling conclusions to be made about alternative routes of absorption (e.g. oral ingestion, hand-mouth contamination).<\/p>\n<\/div>\n<\/div>\n<\/div>\n<div class=\"accordion-group\">\n<h2 class=\"accordion-heading\"><button class=\"accordion-toggle\" data-toggle=\"collapse\"  href=\"#collapse_4\" aria-expanded=\"false\" aria-controls=\"collapse_4\" id=\"collapse_button_4\"> Study on the efficacy of skin-cleansing procedures and the effects of antidotes in cases of hydrofluoric-acid contamination (Phases I\u2013IV) <\/button><\/h2>\n<div id=\"collapse_4\" class=\"accordion-body\" aria-labelledby=\"collapse_button_4\">\n<div class=\"accordion-inner clearfix\">\n<p>funded by the <em>Berufsgenossenschaft Energie Textil Elektro Medienerzeugnisse<\/em> (BG ETEM)<\/p>\n<p>Contact person: <span class=\"fau-person person liste-person\"><span itemscope itemtype=\"http:\/\/schema.org\/Person\"><a href=\"https:\/\/www.ipasum.med.fau.de\/person\/sonja-kilo\/\"><span itemprop=\"name\"><span itemprop=\"honorificPrefix\">PD Dr. med.<\/span> <span class=\"fullname\"><span itemprop=\"givenName\">Sonja<\/span> <span itemprop=\"familyName\">Kilo<\/span><\/span><\/span><\/a><\/span><\/span> (Dr. Gintautas Korinth)<\/p>\n<p>Hydrofluoric acid is the aqueous solution of hydrogen fluoride. Due to its properties, which are clearly distinct from those of other acids, hydrofluoric acid is essential for some industrial branches, such as the petrochemical industry (refinement of mineral oils during fuel manufacture) and the electronics industry. In these industries, the ability of hydrofluoric acid to corrode glass (e.g. dissolve silicates) is employed in the production of circuit boards. Hydrofluoric acid is also required as a starting substance for the production of chemical fluoride compounds. Polytetrafluoroethylene (Gore-Tex<sup>\u00ae<\/sup>, textile refinement) is one such compound.<\/p>\n<p>From a chemical perspective, hydrofluoric acid is a relatively weak acid. Since is barely dissociates in an aqueous solution and is only present in a slightly hydrated state, the lipophilic hydrofluoric acid can easily penetrate into and through the skin. This characteristic leads to hydrofluoric acid functioning as a contact poison, especially at lower concentrations, which means it can be absorbed into the skin without damaging its surface. In contrast, hydrofluoric acid presents an immediate, superficial, and acid-typical corrosive injury pattern in higher concentrations. The greatest danger posed by hydrofluoric acid to humans is its effect as a systemic calcium scavenger. Calcium is essential for many physiological and biological processes, which can only partially take place, if at all, in cases of insufficient calcium supply. Physiologically, calcium loss causes a shift in other ions (potassium, among others), which leads to an ion imbalance and potentially to cardiac arrest.<\/p>\n<p>Phase I: Development of a human-skin <em>ex-vivo <\/em>model for the investigation of skin damage by irritating chemical substances using hydrofluoric acid as an example<\/p>\n<p>Using the diffusion-cell method established by Franz (1975), excised human skin is examined with respect to the dermal penetration of hydrofluoric acid.<\/p>\n<p><a href=\"https:\/\/www.ipasum.med.fau.de\/files\/2018\/12\/Diffusionszelle.pdf\"><strong><em><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-1907 aligncenter\" src=\"https:\/\/arbeitsmedizin.cms.rrze.uni-erlangen.de\/files\/2018\/11\/Diffusionszelle-300x151.png\" alt=\"\" srcset=\"https:\/\/www.ipasum.med.fau.de\/files\/2018\/11\/Diffusionszelle-300x151.png 300w, https:\/\/www.ipasum.med.fau.de\/files\/2018\/11\/Diffusionszelle-768x388.png 768w, https:\/\/www.ipasum.med.fau.de\/files\/2018\/11\/Diffusionszelle-1024x517.png 1024w, https:\/\/www.ipasum.med.fau.de\/files\/2018\/11\/Diffusionszelle-297x150.png 297w, https:\/\/www.ipasum.med.fau.de\/files\/2018\/11\/Diffusionszelle-220x111.png 220w, https:\/\/www.ipasum.med.fau.de\/files\/2018\/11\/Diffusionszelle-218x110.png 218w, https:\/\/www.ipasum.med.fau.de\/files\/2018\/11\/Diffusionszelle-140x70.png 140w, https:\/\/www.ipasum.med.fau.de\/files\/2018\/11\/Diffusionszelle-931x470.png 931w, https:\/\/www.ipasum.med.fau.de\/files\/2018\/11\/Diffusionszelle-145x73.png 145w, https:\/\/www.ipasum.med.fau.de\/files\/2018\/11\/Diffusionszelle.png 1638w\" \/><\/em><\/strong><\/a><\/p>\n<p><strong>Figure 4: Static diffusion cell per T. J. Franz (Percutaneous absorption: On the relevance of <em>in vitro<\/em> data. J Invest Dermatol 64: 190\u2013195).<\/strong><\/p>\n<p>Since diffusion cells can keep excised human skin viable for a limited period of time, the skin can react to irritants to a certain extent. At a certain point in time during hydrofluoric-acid exposure, any skin changes are characterised macroscopically and histologically. Moreover, biochemical examinations for the measurement of early skin damage are performed.<\/p>\n<p>Phase II \u2013 Investigation of the efficacy of various recommended skin-cleansing measures (antidotes) for the decontamination of the skin after hydrofluoric-acid exposure with the model developed in Phase\u00a0I of the study<\/p>\n<p>Due to the systemically toxic and locally destructive consequence of dermal exposure to hydrofluoric acid, even at low concentrations, it is absolutely necessary to test decontamination measures. First-aid recommendations include:<\/p>\n<ul>\n<li>thoroughly rinsing the skin with water and then massaging in a 2.5% calcium-gluconate gel<\/li>\n<li>when using Hexafluorine<sup>\u00ae<\/sup> (Prevor), which was specially developed for hydrofluoric-acid exposure, it is recommended to treat the skin without washing beforehand<\/li>\n<li>emergency plans recommended polyethylene glycol (PEG) 400 (Lutrol<sup>\u00ae<\/sup>, BASF) as the primary cleansing agent before treatment with a calcium-gluconate gel<\/li>\n<li>in some cases, PEG\u00a0400 is recommended as the sole antidote for the practice of occupational medicine<\/li>\n<\/ul>\n<p>In this phase, a skin-cleansing model must be developed based on the model for examination of fluoride penetration after hydrofluoric-acid contamination, as developed in Phase\u00a0I; moreover, common decontamination strategies used in practice must be compared.<\/p>\n<p>Phase III \u2013 Investigation of early decontamination measures after hydrofluoric-acid exposure, of the long-term penetration behaviour of fluoride, of changes to skin temperature and intradermal pH after hydrofluoric-acid exposure, and alternative decontamination strategies<\/p>\n<p>In this phase, the following questions must be examined in more detail:<\/p>\n<ul>\n<li>efficacy of early decontamination after hydrofluoric-acid exposure<\/li>\n<li>investigation of the long-term penetration behaviour (over 72\u00a0hours) of fluoride after hydrofluoric-acid exposure<\/li>\n<li>investigation of intradermal pH and skin temperature after hydrofluoric-acid exposure<\/li>\n<\/ul>\n<p>Phase IV 1 \u2013 Investigation of alternative decontamination strategies after careful consideration of intradermal pH after hydrofluoric-acid exposure<\/p>\n<p>In this phase, it must be examined how a shift in pH influences the penetration of fluoride through human skin.<\/p>\n<p>If applicable, various decontamination techniques should be evaluated against the background of all new information and adapted wherever necessary.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n\n","protected":false},"excerpt":{"rendered":"","protected":false},"author":1688,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_rrze_cache":"enabled","_rrze_multilang_single_locale":"en_GB","_rrze_multilang_single_source":"https:\/\/arbeitsmedizin.cms.rrze.uni-erlangen.de\/?page_id=1957","footnotes":""},"page_category":[],"page_tag":[],"class_list":["post-4430","page","type-page","status-publish","hentry","en-GB"],"_links":{"self":[{"href":"https:\/\/www.ipasum.med.fau.de\/wp-json\/wp\/v2\/pages\/4430","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.ipasum.med.fau.de\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.ipasum.med.fau.de\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.ipasum.med.fau.de\/wp-json\/wp\/v2\/users\/1688"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ipasum.med.fau.de\/wp-json\/wp\/v2\/comments?post=4430"}],"version-history":[{"count":5,"href":"https:\/\/www.ipasum.med.fau.de\/wp-json\/wp\/v2\/pages\/4430\/revisions"}],"predecessor-version":[{"id":4541,"href":"https:\/\/www.ipasum.med.fau.de\/wp-json\/wp\/v2\/pages\/4430\/revisions\/4541"}],"wp:attachment":[{"href":"https:\/\/www.ipasum.med.fau.de\/wp-json\/wp\/v2\/media?parent=4430"}],"wp:term":[{"taxonomy":"page_category","embeddable":true,"href":"https:\/\/www.ipasum.med.fau.de\/wp-json\/wp\/v2\/page_category?post=4430"},{"taxonomy":"page_tag","embeddable":true,"href":"https:\/\/www.ipasum.med.fau.de\/wp-json\/wp\/v2\/page_tag?post=4430"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}