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P. Rice - One of the best experts on this subject based on the ideXlab platform.
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In vitro Skin Absorption and decontamination of sulphur mustard: comparison of human and pig-ear Skin.
Journal of applied toxicology : JAT, 2001Co-Authors: Robert P. Chilcott, John Jenner, S. A. M. Hotchkiss, P. RiceAbstract:The aim of this study was to evaluate the use of an in vitro Skin diffusion cell system as a model for assessing decontaminants against the chemical warfare agent sulphur mustard (SM). The in vitro Absorption rates of SM through heat-separated human (157 ± 66 µg cm−2 h−1) and pig-ear (411 ± 175 µg cm−2 h−1) epidermal membranes were in agreement with previous in vivo studies that quoted Skin Absorption rates of 150 and 366 mu g cm−2 h−1, respectively. Decontaminants (fuller's earth, Ambergard and BDH spillage granules) were ranked in order of effectiveness by measuring the Skin Absorption rates and the percentage of applied dose of SM that penetrated human and pig-ear epidermal membranes. The effectiveness of fuller's earth measured in this in vitro study using human epidermal membranes was in agreement with a previous in vivo human volunteer study. Similarly, the effectiveness of fuller's earth and Ambergard measured in vitro with pig-ear epidermal membranes was in agreement with a previous in vivo study conducted on rats. However, there was complete disparity in the ranking of decontaminants between human and pig-ear epidermal membranes measured in vitro. Thus, although pig-ear Skin may be a relatively good model for predicting the human Skin Absorption of SM, it is a poor model for testing decontamination systems. The results of this study further validate the use of Franz-type glass diffusion cells containing human epidermal membranes as a model for predicting in vivo human Skin Absorption. Copyright © 2001 John Wiley & Sons, Ltd.
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human Skin Absorption of bis 2 chloroethyl sulphide sulphur mustard in vitro
Journal of Applied Toxicology, 2000Co-Authors: Robert P. Chilcott, John Jenner, S. A. M. Hotchkiss, W. Carrick, P. RiceAbstract:The purpose of this study was to measure the Absorption and intra-epidermal fate of 35S-radiolabelled sulphur mustard (35SM) in human breast Skin in vitro. Skin (full-thickness or heat-separated epidermis) was placed into static diffusion cells and was exposed to droplets of liquid 35SM or saturated 35SM vapour. Amounts of 35SM penetrating the Skin were measured from which Skin Absorption rates were calculated. Unbound radiolabel was washed from the surface, extracted from the Skin and analysed to determine the identity of the radiolabelled species in order to measure the extent of hydrolysis of sulphur mustard. Penetration rates of liquid 35SM measured in vitro (71–294 μg cm−2 h−1) were in agreement with those measured previously in vivo using human volunteers (60–240 μg cm−2 h−1). Rates of liquid 35SM Skin Absorption under occluded, infinite dose conditions were highest through heat-separated epidermal membranes (294 ± 58 μg cm−2 h−1) and lowest through full-thickness Skin (71 ± 14 μg cm−2 h−1). Fluxes of saturated 35SM vapour (110 ± 75 μg cm−2 h−1) through heat-separated membranes were similar to those previously measured through human forearm Skin in vivo (162 μg cm−2 h−1). Although hydrolysis of 35SM did occur, both on the surface and within the Skin, it accounted for only a small percentage of the total applied dose (<2.7 ± 1.2%). The difference in total amount of liquid 35SM penetrated between occluded and unoccluded conditions in vitro (79 ± 14%) was similar to that lost as vapour from unoccluded Skin in vivo (80%). A substantial reservoir of 35SM (14–36% of the applied dose) was measured within heat-separated epidermal membranes for up to 24 h which may have significant implications for the management of personnel exposed to sulphur mustard. © Crown copyright 2000. Reproduced with the permission of Her Majesty's Stationery Office. Published by John Wiley & Sons.
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Human Skin Absorption of bis-2-(chloroethyl)sulphide (sulphur mustard) in vitro
Journal of applied toxicology : JAT, 2000Co-Authors: Robert P. Chilcott, John Jenner, S. A. M. Hotchkiss, W. Carrick, P. RiceAbstract:The purpose of this study was to measure the Absorption and intra-epidermal fate of 35S-radiolabelled sulphur mustard (35SM) in human breast Skin in vitro. Skin (full-thickness or heat-separated epidermis) was placed into static diffusion cells and was exposed to droplets of liquid 35SM or saturated 35SM vapour. Amounts of 35SM penetrating the Skin were measured from which Skin Absorption rates were calculated. Unbound radiolabel was washed from the surface, extracted from the Skin and analysed to determine the identity of the radiolabelled species in order to measure the extent of hydrolysis of sulphur mustard. Penetration rates of liquid 35SM measured in vitro (71–294 μg cm−2 h−1) were in agreement with those measured previously in vivo using human volunteers (60–240 μg cm−2 h−1). Rates of liquid 35SM Skin Absorption under occluded, infinite dose conditions were highest through heat-separated epidermal membranes (294 ± 58 μg cm−2 h−1) and lowest through full-thickness Skin (71 ± 14 μg cm−2 h−1). Fluxes of saturated 35SM vapour (110 ± 75 μg cm−2 h−1) through heat-separated membranes were similar to those previously measured through human forearm Skin in vivo (162 μg cm−2 h−1). Although hydrolysis of 35SM did occur, both on the surface and within the Skin, it accounted for only a small percentage of the total applied dose (
Marie-alexandrine Bolzinger - One of the best experts on this subject based on the ideXlab platform.
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The effect of vehicle on Skin Absorption of Mg2+ and Ca2+ from thermal spring water.
International journal of cosmetic science, 2020Co-Authors: Małgorzata Tarnowska, Yves Chevalier, Stéphanie Briançon, J. Resende De Azevedo, D. Arquier, C. Barratier, Marie-alexandrine BolzingerAbstract:OBJECTIVE Thermal spring waters (TSW) are commonly used as active ingredients in cosmetics. Their biological activities directly depend on the ionic composition of the spring. However, in order to exhibit beneficial properties, the minerals need to reach viable Skin layers. The present study addresses the incorporation of marketed TSW in model cosmetic formulations and the impact of the formulation on Skin Absorption of magnesium and calcium ions that are known to improve Skin barrier function. METHODS Marketed TSW was introduced into five formulations. Liposomes were prepared using saturated or unsaturated phospholipids mixed with cholesterol by the thin layer evaporation technique. Emulsions water-in-oil (W/O), oil-in-water (O/W) or double: water-in-oil-in-water (W/O/W) were prepared by high-shear mixing. Skin Absorption of Mg2+ and Ca2+ from those formulations was studied in vitro using static Franz diffusion cells under infinite dose condition and under occlusion of the apparatus. RESULTS Mg2+ and Ca2+ penetrate Skin samples from TSW. Encapsulating TSW into double emulsion (TSW/O/W) increased Skin Absorption of both cations of interest and kept the Ca2+ /Mg2+ ratio equal to that of TSW in each Skin layer. The dermal Absorption of Mg2+ from the double emulsion departs from both single emulsions. Application of liposome suspension improved the Skin Absorption of Ca2+ while keeping constant that of Mg2+ , leading to unbalanced Ca2+ /Mg2+ ratio inside Skin. CONCLUSION The beneficial effects of TSW are not only due to their action on the Skin surface. Their active components, especially Ca2+ and Mg2+ cations, reach viable Skin layers in a formulation-dependent manner. The distribution of ions inside Skin depends on the type of formulation.
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Skin Absorption of Anions: Part One. Methodology for In Vitro Cutaneous Absorption Measurements
Pharmaceutical Research, 2016Co-Authors: Raphaël Paweloszek, Nicole Gilon-delepine, Jocelyne Pelletier, Yves Chevalier, Stéphanie Briançon, Marie-alexandrine BolzingerAbstract:PurposeMeasurement of Skin Absorption of ions requires specific experimental protocols regarding the use of pig Skin as a model, the viability of excised Skin in water medium over 24 h, the presence of endogenous ions, and evaluation of the contributions of facilitated transport through ion channels and ion transporters.MethodAbsorption experiments of halide anions F^−, Cl^−, Br^− and I^− in excised Skin were performed in Franz diffusion cells. Experiments were performed on human and porcine Skin under various conditions so as to define and validate experimental protocols.ResultsThe distributions of endogenous ions and the Absorption kinetics of halide ions were similar in both porcine and human Skin models. Fresh Skin kept its viability over 24 h in salt-free water, allowing experiments following OECD guidelines. Permeation increased in the order F^− < Cl^− < Br^− < I^− for all receptor media and Skin samples. Absorption was larger in fresh Skin due to the transport through chloride channels or exchangers.ConclusionSkin Absorption experiments of ions in Franz cells rely on working with fresh excised Skin (human or porcine) and pure water as receptor fluid. Experiments with chloride blockers or frozen/thawed Skin allow discriminating passive diffusion and facilitated transport.
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Skin Absorption of anions: part one. Methodology for in vitro cutaneousAbsorption measurements
Pharmaceutical Research, 2016Co-Authors: Raphaël Paweloszek, Jocelyne Pelletier, Yves Chevalier, Stéphanie Briançon, Nicole Delépine-gilon, Marie-alexandrine BolzingerAbstract:Measurement of Skin Absorption of ions requires specific experimental protocols regarding the use of pig Skin as a model, the viability of excised Skin in water medium over 24 h, the presence of endogenous ions, and evaluation of the contributions of facilitated transport through ion channels and ion transporters. Absorption experiments of halide anions F-, Cl-, Br- and I- in excised Skin were performed in Franz diffusion cells. Experiments were performed on human and porcine Skin under various conditions so as to define and validate experimental protocols. The distributions of endogenous ions and the Absorption kinetics of halide ions were similar in both porcine and human Skin models. Fresh Skin kept its viability over 24 h in salt-free water, allowing experiments following OECD guidelines. Permeation increased in the order F- < Cl- < Br- < I- for all receptor media and Skin samples. Absorption was larger in fresh Skin due to the transport through chloride channels or exchangers. Skin Absorption experiments of ions in Franz cells rely on working with fresh excised Skin (human or porcine) and pure water as receptor fluid. Experiments with chloride blockers or frozen/thawed Skin allow discriminating passive diffusion and facilitated transport.
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Skin Absorption of anions: part two. Skin Absorption of halide ions
Pharmaceutical Research, 2016Co-Authors: Raphaël Paweloszek, Jocelyne Pelletier, Yves Chevalier, Stéphanie Briançon, Nicole Delépine-gilon, Marie-alexandrine BolzingerAbstract:The purpose of the study was to sort Skin penetration of anions with respect to their properties and to assess their mechanisms of penetration. Aqueous solutions of halides at two concentrations were prepared and quantitative penetration studies were carried out for 24 h using Franz diffusion cells. The iodide permeation was also measured after blocking of anion channels and transporters to investigate the role of this specific transport. Absorption of halide ions into Skin revealed large differences of transport between these anions according to the Hofmeister series. Increasing steady-state fluxes and lag times in the order F- < Cl- < Br- < I- were observed in permeation experiments. The steady-state fluxes were proportional to the concentration for each halide ion. Longer lag times for iodide or bromide ions were explained by the ability of such sticky chaotropic anions to interact with apolar lipids especially in the stratum corneum. Inhibiting ion exchangers and channels decreased the flux of iodide ions by 75%, showing the high contribution of the facilitated transport over the passive pathway. Ions transport had contributions coming from passive diffusion through the Skin layers and transport mediated by ion channels and binding to ion transporters.
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Skin Absorption of Anions: Part One. Methodology for In Vitro Cutaneous Absorption Measurements
Pharmaceutical research, 2016Co-Authors: Raphaël Paweloszek, Nicole Gilon-delepine, Jocelyne Pelletier, Yves Chevalier, Stéphanie Briançon, Marie-alexandrine BolzingerAbstract:Purpose Measurement of Skin Absorption of ions requires specific experimental protocols regarding the use of pig Skin as a model, the viability of excised Skin in water medium over 24 h, the presence of endogenous ions, and evaluation of the contributions of facilitated transport through ion channels and ion transporters.
Robert P. Chilcott - One of the best experts on this subject based on the ideXlab platform.
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in vivo Skin Absorption and distribution of the nerve agent vx o ethyl s 2 diisopropylamino ethyl methylphosphonothioate in the domestic white pig
Human & Experimental Toxicology, 2005Co-Authors: Robert P. Chilcott, Christopher H. Dalton, Ira Hill, C. M. Davison, K. L. Blohm, E. D. Clarkson, Murray G. HamiltonAbstract:The purpose of this study was to characterize the Skin Absorption and distribution of VX (O-ethyl-S-[2 (diisopropylamino)ethyl] methylphosphonothioate) in the domestic pig in order to evaluate the animal as a potential model for assessing pretreatments against toxic anti-cholinesterase compounds. A liquid droplet (equivalent to a 2 x LD50 dose) of radiolabelled VX was applied to the inner ear-Skin of each anaesthetized animal. Blood and tissue samples (liver, lung, kidney, heart and Skin exposure sites) were obtained post-mortem. The amount of radioactivity in each sample was measured by liquid scintillation counting, from which the Skin Absorption rate and dose distribution of VX were calculated. A substantial proportion (22 +/- 3%) of the applied dose remained within the Skin at the site of application. It is conceivable that strategies to minimize or remove this reservoir may be of benefit in the early treatment of VX-exposed casualties. Image analysis of autoradiographs of exposed Skin sites indicated that each milligram of radioactive VX covered an area of 1.2 +/- 0.5 cm2. The average Skin Absorption rate of 14C-VX was 661 +/- 126 microg/cm2 per hour. Comparison of these data with previous studies suggests that human Skin is less permeable to VX than pig Skin, but VX spreads over a greater surface area when applied to human Skin. Thus, paradoxically, while pig-ear Skin is more permeable than human Skin, the difference in Skin surface spreading may lead to the Absorption of an equivalent systemic dose.
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In vivo Skin Absorption and distribution of the nerve agent VX (O-ethyl-S-[2(diisopropylamino)ethyl] methylphosphonothioate) in the domestic white pig
Human & experimental toxicology, 2005Co-Authors: Robert P. Chilcott, Christopher H. Dalton, Ira Hill, C. M. Davison, K. L. Blohm, E. D. Clarkson, Murray G. HamiltonAbstract:The purpose of this study was to characterize the Skin Absorption and distribution of VX (Oethyl–S–[2(diisopropylamino)ethyl] methylphosphonothioate) in the domestic pig in order to evaluate the an...
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In vitro Skin Absorption and decontamination of sulphur mustard: comparison of human and pig-ear Skin.
Journal of applied toxicology : JAT, 2001Co-Authors: Robert P. Chilcott, John Jenner, S. A. M. Hotchkiss, P. RiceAbstract:The aim of this study was to evaluate the use of an in vitro Skin diffusion cell system as a model for assessing decontaminants against the chemical warfare agent sulphur mustard (SM). The in vitro Absorption rates of SM through heat-separated human (157 ± 66 µg cm−2 h−1) and pig-ear (411 ± 175 µg cm−2 h−1) epidermal membranes were in agreement with previous in vivo studies that quoted Skin Absorption rates of 150 and 366 mu g cm−2 h−1, respectively. Decontaminants (fuller's earth, Ambergard and BDH spillage granules) were ranked in order of effectiveness by measuring the Skin Absorption rates and the percentage of applied dose of SM that penetrated human and pig-ear epidermal membranes. The effectiveness of fuller's earth measured in this in vitro study using human epidermal membranes was in agreement with a previous in vivo human volunteer study. Similarly, the effectiveness of fuller's earth and Ambergard measured in vitro with pig-ear epidermal membranes was in agreement with a previous in vivo study conducted on rats. However, there was complete disparity in the ranking of decontaminants between human and pig-ear epidermal membranes measured in vitro. Thus, although pig-ear Skin may be a relatively good model for predicting the human Skin Absorption of SM, it is a poor model for testing decontamination systems. The results of this study further validate the use of Franz-type glass diffusion cells containing human epidermal membranes as a model for predicting in vivo human Skin Absorption. Copyright © 2001 John Wiley & Sons, Ltd.
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human Skin Absorption of bis 2 chloroethyl sulphide sulphur mustard in vitro
Journal of Applied Toxicology, 2000Co-Authors: Robert P. Chilcott, John Jenner, S. A. M. Hotchkiss, W. Carrick, P. RiceAbstract:The purpose of this study was to measure the Absorption and intra-epidermal fate of 35S-radiolabelled sulphur mustard (35SM) in human breast Skin in vitro. Skin (full-thickness or heat-separated epidermis) was placed into static diffusion cells and was exposed to droplets of liquid 35SM or saturated 35SM vapour. Amounts of 35SM penetrating the Skin were measured from which Skin Absorption rates were calculated. Unbound radiolabel was washed from the surface, extracted from the Skin and analysed to determine the identity of the radiolabelled species in order to measure the extent of hydrolysis of sulphur mustard. Penetration rates of liquid 35SM measured in vitro (71–294 μg cm−2 h−1) were in agreement with those measured previously in vivo using human volunteers (60–240 μg cm−2 h−1). Rates of liquid 35SM Skin Absorption under occluded, infinite dose conditions were highest through heat-separated epidermal membranes (294 ± 58 μg cm−2 h−1) and lowest through full-thickness Skin (71 ± 14 μg cm−2 h−1). Fluxes of saturated 35SM vapour (110 ± 75 μg cm−2 h−1) through heat-separated membranes were similar to those previously measured through human forearm Skin in vivo (162 μg cm−2 h−1). Although hydrolysis of 35SM did occur, both on the surface and within the Skin, it accounted for only a small percentage of the total applied dose (<2.7 ± 1.2%). The difference in total amount of liquid 35SM penetrated between occluded and unoccluded conditions in vitro (79 ± 14%) was similar to that lost as vapour from unoccluded Skin in vivo (80%). A substantial reservoir of 35SM (14–36% of the applied dose) was measured within heat-separated epidermal membranes for up to 24 h which may have significant implications for the management of personnel exposed to sulphur mustard. © Crown copyright 2000. Reproduced with the permission of Her Majesty's Stationery Office. Published by John Wiley & Sons.
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Human Skin Absorption of bis-2-(chloroethyl)sulphide (sulphur mustard) in vitro
Journal of applied toxicology : JAT, 2000Co-Authors: Robert P. Chilcott, John Jenner, S. A. M. Hotchkiss, W. Carrick, P. RiceAbstract:The purpose of this study was to measure the Absorption and intra-epidermal fate of 35S-radiolabelled sulphur mustard (35SM) in human breast Skin in vitro. Skin (full-thickness or heat-separated epidermis) was placed into static diffusion cells and was exposed to droplets of liquid 35SM or saturated 35SM vapour. Amounts of 35SM penetrating the Skin were measured from which Skin Absorption rates were calculated. Unbound radiolabel was washed from the surface, extracted from the Skin and analysed to determine the identity of the radiolabelled species in order to measure the extent of hydrolysis of sulphur mustard. Penetration rates of liquid 35SM measured in vitro (71–294 μg cm−2 h−1) were in agreement with those measured previously in vivo using human volunteers (60–240 μg cm−2 h−1). Rates of liquid 35SM Skin Absorption under occluded, infinite dose conditions were highest through heat-separated epidermal membranes (294 ± 58 μg cm−2 h−1) and lowest through full-thickness Skin (71 ± 14 μg cm−2 h−1). Fluxes of saturated 35SM vapour (110 ± 75 μg cm−2 h−1) through heat-separated membranes were similar to those previously measured through human forearm Skin in vivo (162 μg cm−2 h−1). Although hydrolysis of 35SM did occur, both on the surface and within the Skin, it accounted for only a small percentage of the total applied dose (
Leila Yazdanpanah - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of Skin Absorption of the Citrullus colocynthis in treatment of type II diabetic patients
Journal of Diabetes & Metabolic Disorders, 2020Co-Authors: Akram Ahangarpour, Rafie Belali, Fatemeh Bineshfar, Shokoh Javadzadeh, Leila YazdanpanahAbstract:Background and purpose Nowadays, among the herbal medicines utilized to treat diabetes, Citrullus colocynthis (CCT) is highly noticeable as it reduces blood glucose (BG) and stimulating insulin secretion. However, long-term oral consumption of this herbal medicine has often associated with digestive complications. In this study, Skin Absorption of CCT as a new therapeutic approach in the treatment of type II diabetic patients has been surveyed. Materials and methods 40 patients with type II diabetic (aged 45–65) were selected. Participants were asked for placing their metatarsus daily in a decoction containing 2% CCT solution for 40–60 min each day and continuing that for 10 days. Blood and urine samples of patients collected at the beginning and the end of the study. The samples were examined for the BG levels, serum insulin content, lipid profiles, hepatic enzymes, urea, creatinine, and microalbuminuria, The quantitative insulin sensitivity check index (QUICKI), Homeostatic Model Assessment of Insulin Resistance (HOMA-IR), homeostasis model assessment of β-cell function (HOMA-β) and disposition index (DI) indicators were also calculated. Results Local treatment of CCT could significantly decrease BG levels, stimulate insulin secretion and improve the function of pancreatic beta cells. It also decreased serum urea levels comparing to pre-treatment levels ( p
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Evaluation of Skin Absorption of the Citrullus colocynthis in treatment of type II diabetic patients.
Journal of diabetes and metabolic disorders, 2020Co-Authors: Akram Ahangarpour, Rafie Belali, Fatemeh Bineshfar, Shokoh Javadzadeh, Leila YazdanpanahAbstract:Nowadays, among the herbal medicines utilized to treat diabetes, Citrullus colocynthis (CCT) is highly noticeable as it reduces blood glucose (BG) and stimulating insulin secretion. However, long-term oral consumption of this herbal medicine has often associated with digestive complications. In this study, Skin Absorption of CCT as a new therapeutic approach in the treatment of type II diabetic patients has been surveyed. 40 patients with type II diabetic (aged 45–65) were selected. Participants were asked for placing their metatarsus daily in a decoction containing 2% CCT solution for 40–60 min each day and continuing that for 10 days. Blood and urine samples of patients collected at the beginning and the end of the study. The samples were examined for the BG levels, serum insulin content, lipid profiles, hepatic enzymes, urea, creatinine, and microalbuminuria, The quantitative insulin sensitivity check index (QUICKI), Homeostatic Model Assessment of Insulin Resistance (HOMA-IR), homeostasis model assessment of β-cell function (HOMA-β) and disposition index (DI) indicators were also calculated. Local treatment of CCT could significantly decrease BG levels, stimulate insulin secretion and improve the function of pancreatic beta cells. It also decreased serum urea levels comparing to pre-treatment levels (p
Ulrich F. Schaefer - One of the best experts on this subject based on the ideXlab platform.
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Basic Mathematics in Skin Absorption
Percutaneous Penetration Enhancers Drug Penetration Into Through the Skin, 2017Co-Authors: Dominik Selzer, Ulrich F. Schaefer, Claus-michael Lehr, Steffi HansenAbstract:Frequently, analysis of Skin Absorption does not only require the careful evaluation of experimental data but also the fundamental understanding of underlying physics to apply the appropriate mathematical concepts to attain insight into transport kinetics. This chapter will introduce the basic mathematics which are necessary to evaluate Skin permeation and Skin penetration experiments. The most common approaches are introduced and reviewed critically concerning their applicability as well as limitation. Solution techniques for dealing with infinite and finite dose cases are presented. Several analytical solutions for specific cases are presented and discussed, as well as an outlook on more advanced
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A strategy for in-silico prediction of Skin Absorption in man.
European journal of pharmaceutics and biopharmaceutics : official journal of Arbeitsgemeinschaft fur Pharmazeutische Verfahrenstechnik e.V, 2015Co-Authors: Dominik Selzer, Claus-michael Lehr, Dirk Neumann, Heike Neumann, Karl-heinz Kostka, Ulrich F. SchaeferAbstract:Abstract For some time, in-silico models to address substance transport into and through the Skin are gaining more and more importance in different fields of science and industry. In particular, the mathematical prediction of in-vivo Skin Absorption is of great interest to overcome ethical and economical issues. The presented work outlines a strategy to address this problem and in particular, investigates in-vitro and in-vivo Skin penetration experiments of the model compound flufenamic acid solved in an ointment by means of a mathematical model. Experimental stratum corneum concentration–depth profiles (SC–CDP) for various time intervals using two different in-vitro systems (Franz diffusion cell, Saarbruecken penetration model) were examined and simulated with the help of a highly optimized three compartment numerical diffusion model and compared to the findings of SC–CDPs of the in-vivo scenario. Fitted model input parameters (diffusion coefficient and partition coefficient with respect to the stratum corneum) for the in-vitro infinite dose case could be used to predict the in-use conditions in-vitro. Despite apparent differences in calculated partition coefficients between in-vivo and in-vitro studies, prediction of in-vivo scenarios from input parameters calculated from the in-vitro case yielded reasonable results.
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From the structure of the Skin barrier and dermal formulations to in vitro transport models for Skin Absorption: Skin research in the Netherlands and in Germany.
Skin pharmacology and physiology, 2013Co-Authors: Maike Windbergs, Ulrich F. Schaefer, Steffi Hansen, Claus-michael Lehr, A Schroeter, Joke A BouwstraAbstract:This review presents an overview of German and Dutch research institutions and their studies in the field of Skin drug delivery and adjacent topics. In the Netherlands, the involved research groups are mainly localized in Leiden, whereas in Germany the Skin research institutions are spread over the whole country. The scientific studies in the Netherlands focus on the in-depth analysis of human Skin composition and its individual components as well as on the development and characterization of dermal drug delivery systems ranging from liquid crystalline systems and vesicles up to microneedles with an emphasis on examining the interactions of these drug delivery systems with the human Skin in vitro and in vivo. In Germany, the individual areas of research span from in-depth investigations on various drug delivery systems intended for Skin application and the development of novel in vitro models for Skin Absorption testing up to in vivo studies focusing on the biological performance of topically applied actives. Furthermore, sophisticated analytical techniques are applied for the elucidation of Skin assembly and transport processes. In addition, experimentally derived data are correlated with advanced computational modelling. Even though the individual research topics in the Netherlands and Germany are quite diverse, the exchange of knowledge and interdisciplinary collaborations between the two neighbouring countries were and are still frequently made. In this context, the review aims at highlighting crosslinks between the different institutions and individual persons to complete the picture. For each institution, the principal investigators and their studies are presented and the upcoming young scientists are introduced as an outlook for the field. This review does not claim completeness, but is rather intended to give a general overview of Dutch and German research in the field of Skin drug delivery and adjacent topics.
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from the structure of the Skin barrier and dermal formulations to in vitro transport models for Skin Absorption Skin research in the netherlands and in germany
Skin Pharmacology and Physiology, 2013Co-Authors: Maike Windbergs, Ulrich F. Schaefer, Steffi Hansen, Claus-michael Lehr, A Schroeter, Joke A BouwstraAbstract:This review presents an overview of German and Dutch research institutions and their studies in the field of Skin drug delivery and adjacent topics. In the Netherlands, the involved research groups are mainly localized in Leiden, whereas in Germany the Skin research institutions are spread over the whole country. The scientific studies in the Netherlands focus on the in-depth analysis of human Skin composition and its individual components as well as on the development and characterization of dermal drug delivery systems ranging from liquid crystalline systems and vesicles up to microneedles with an emphasis on examining the interactions of these drug delivery systems with the human Skin in vitro and in vivo. In Germany, the individual areas of research span from in-depth investigations on various drug delivery systems intended for Skin application and the development of novel in vitro models for Skin Absorption testing up to in vivo studies focusing on the biological performance of topically applied actives. Furthermore, sophisticated analytical techniques are
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Improved input parameters for diffusion models of Skin Absorption
Advanced drug delivery reviews, 2012Co-Authors: Steffi Hansen, Claus-michael Lehr, Ulrich F. SchaeferAbstract:To use a diffusion model for predicting Skin Absorption requires accurate estimates of input parameters on model geometry, affinity and transport characteristics. This review summarizes methods to obtain input parameters for diffusion models of Skin Absorption focusing on partition and diffusion coefficients. These include experimental methods, extrapolation approaches, and correlations that relate partition and diffusion coefficients to tabulated physico-chemical solute properties. Exhaustive databases on lipid-water and corneocyte protein-water partition coefficients are presented and analyzed to provide improved approximations to estimate lipid-water and corneocyte protein-water partition coefficients. The most commonly used estimates of lipid and corneocyte diffusion coefficients are also reviewed. In order to improve modeling of Skin Absorption in the future diffusion models should include the vertical stratum corneum heterogeneity, slow equilibration processes, the Absorption from complex non-aqueous formulations, and an improved representation of dermal Absorption processes. This will require input parameters for which no suitable estimates are yet available.
