1
|
Fandrei F, Havrišák T, Opálka L, Engberg O, Smith A, Pullmannová P, Kučerka N, Ondrejčeková V, Demé B, Nováková L, Steinhart M, Vávrová K, Huster D. The Intriguing Molecular Dynamics of Cer[EOS] in Rigid Skin Barrier Lipid Layers Requires Improvement of the Model. J Lipid Res 2023; 64:100356. [PMID: 36948272 PMCID: PMC10154977 DOI: 10.1016/j.jlr.2023.100356] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 03/07/2023] [Accepted: 03/08/2023] [Indexed: 03/24/2023] Open
Abstract
Omega-O-acyl ceramides such as 32-linoleoyloxydotriacontanoyl sphingosine (Cer[EOS]) are essential components of the lipid skin barrier, which protects our body from excessive water loss and the penetration of unwanted substances. These ceramides drive the lipid assembly to epidermal-specific long periodicity phase (LPP), structurally much different than conventional lipid bilayers. Here, we synthesized Cer[EOS] with selectively deuterated segments of the ultralong N-acyl chain or deuterated or 13C-labeled linoleic acid and studied their molecular behavior in a skin lipid model. Solid-state 2H NMR data revealed surprising molecular dynamics for the ultralong N-acyl chain of Cer[EOS] with increased isotropic motion towards the isotropic ester-bound linoleate. The sphingosine moiety of Cer[EOS] is also highly mobile at skin temperature, in stark contrast to the other LPP components, N-lignoceroyl sphingosine acyl, lignoceric acid and cholesterol, which are predominantly rigid. The dynamics of the linoleic chain is quantitatively described by distributions of correlation times and using dynamic detector analysis. These NMR results along with neutron diffraction data suggest an LPP structure with alternating fluid (sphingosine chain-rich), rigid (acyl chain-rich), isotropic (linoleate-rich), rigid (acyl-chain rich), and fluid layers (sphingosine chain-rich). Such an arrangement of the skin barrier lipids with rigid layers separated with two different dynamic "fillings" i) agrees well with ultrastructural data, ii) satisfies the need for simultaneous rigidity (to ensure low permeability) and fluidity (to ensure elasticity, accommodate enzymes or antimicrobial peptides), and iii) offers a straightforward way to remodel the lamellar body lipids into the final lipid barrier.
Collapse
Affiliation(s)
- Ferdinand Fandrei
- Institute of Medical Physics and Biophysics, University of Leipzig, Härtelstr. 16-18, 04275 Leipzig, Germany
| | - Tomáš Havrišák
- Skin Barrier Research Group, Faculty of Pharmacy, Charles University, Akademika Heyrovského 1203, 50005 Hradec Králové, Czech Republic
| | - Lukáš Opálka
- Skin Barrier Research Group, Faculty of Pharmacy, Charles University, Akademika Heyrovského 1203, 50005 Hradec Králové, Czech Republic
| | - Oskar Engberg
- Institute of Medical Physics and Biophysics, University of Leipzig, Härtelstr. 16-18, 04275 Leipzig, Germany
| | - AlbertA Smith
- Institute of Medical Physics and Biophysics, University of Leipzig, Härtelstr. 16-18, 04275 Leipzig, Germany
| | - Petra Pullmannová
- Skin Barrier Research Group, Faculty of Pharmacy, Charles University, Akademika Heyrovského 1203, 50005 Hradec Králové, Czech Republic
| | - Norbert Kučerka
- Faculty of Pharmacy, Comenius University in Bratislava, Odbojárov 10, 832 32 Bratislava, Slovakia
| | - Veronika Ondrejčeková
- Skin Barrier Research Group, Faculty of Pharmacy, Charles University, Akademika Heyrovského 1203, 50005 Hradec Králové, Czech Republic
| | - Bruno Demé
- Institut Laue-Langevin, 71 avenue des Martyrs, CS 20156, 38042 Grenoble, CEDEX 9, France
| | - Lucie Nováková
- Department of Analytical Chemistry, Faculty of Pharmacy, Charles University, Akademika Heyrovského 1203, 50005 Hradec Králové, Czech Republic
| | - Miloš Steinhart
- Institute of Macromolecular Chemistry, Czech Academy of Science in Prague, Heyrovského nám. 2, 162 06 Prague, Czech Republic
| | - Kateřina Vávrová
- Skin Barrier Research Group, Faculty of Pharmacy, Charles University, Akademika Heyrovského 1203, 50005 Hradec Králové, Czech Republic
| | - Daniel Huster
- Institute of Medical Physics and Biophysics, University of Leipzig, Härtelstr. 16-18, 04275 Leipzig, Germany
| |
Collapse
|
2
|
Wang Z, Hu Y, Xue Y, Wu Y, Zeng Q, Chen H, Guo Y, Liang P, Liang T, Shen C, Jiang C, Liu L, Shen Q, Zhu H, Liu Q. 4'-OH as the Action Site of Lipids and MRP1 for Enhanced Transdermal Delivery of Flavonoids. ACS APPLIED MATERIALS & INTERFACES 2023. [PMID: 36913526 DOI: 10.1021/acsami.2c18086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
To date, the transdermal delivery study mainly focused on the drug delivery systems' design and efficacy evaluation. Few studies reported the structure-affinity relationship of the drug with the skin, further revealing the action sites of the drugs for enhanced permeation. Flavonoids attained a considerable interest in transdermal administration. The aim is to develop a systematic approach to evaluate the substructures that were favorable for flavonoid delivery into the skin and understand how these action sites interacted with lipids and bound to multidrug resistance protein 1 (MRP1) for enhanced transdermal delivery. First, we investigated the permeation properties of various flavonoids on the porcine skin or rat skin. We found that 4'-OH (hydroxyl group on the carbon 4' position) rather than 7-OH on the flavonoids was the key group for flavonoid permeation and retention, while 4'-OCH3 and -CH2═CH2-CH-(CH3)2 were unfavorable for drug delivery. 4'-OH could decrease flavonoids' lipophilicity to an appropriate log P and polarizability for better transdermal drug delivery. In the stratum corneum, flavonoids used 4'-OH as a hand to specifically grab the C═O group of the ceramide NS (Cer), which increased the miscibility of flavonoids and Cer and then disturbed the lipid arrangement of Cer, thereby facilitating their penetration. Subsequently, we constructed overexpressed MRP1 HaCaT/MRP1 cells by permanent transfection of human MRP1 cDNA in wild HaCaT cells. In the dermis, we observed that 4'-OH, 7-OH, and 6-OCH3 substructures were involved in H-bond formation within MRP1, which increased the flavonoid affinity with MRP1 and flavonoid efflux transport. Moreover, the expression of MRP1 was significantly enhanced after the treatment of flavonoids on the rat skin. Collectively, 4'-OH served as the action site for increased lipid disruption and enhanced affinity for MRP1, which facilitate the transdermal delivery of flavonoids, providing valuable guidelines for molecular modification and drug design of flavonoids.
Collapse
Affiliation(s)
- Zhuxian Wang
- School of Traditional Chinese Medicine, Southern Medical University, 1838 North Guangzhou Avenue, Guangzhou 510515, China
| | - Yi Hu
- School of Traditional Chinese Medicine, Southern Medical University, 1838 North Guangzhou Avenue, Guangzhou 510515, China
| | - Yaqi Xue
- School of Traditional Chinese Medicine, Southern Medical University, 1838 North Guangzhou Avenue, Guangzhou 510515, China
| | - Yufan Wu
- School of Traditional Chinese Medicine, Southern Medical University, 1838 North Guangzhou Avenue, Guangzhou 510515, China
| | - Quanfu Zeng
- School of Traditional Chinese Medicine, Southern Medical University, 1838 North Guangzhou Avenue, Guangzhou 510515, China
| | - Hongkai Chen
- School of Traditional Chinese Medicine, Southern Medical University, 1838 North Guangzhou Avenue, Guangzhou 510515, China
| | - Yinglin Guo
- School of Traditional Chinese Medicine, Southern Medical University, 1838 North Guangzhou Avenue, Guangzhou 510515, China
| | - Peiyi Liang
- School of Traditional Chinese Medicine, Southern Medical University, 1838 North Guangzhou Avenue, Guangzhou 510515, China
| | - Tao Liang
- School of Traditional Chinese Medicine, Southern Medical University, 1838 North Guangzhou Avenue, Guangzhou 510515, China
| | - Chunyan Shen
- School of Traditional Chinese Medicine, Southern Medical University, 1838 North Guangzhou Avenue, Guangzhou 510515, China
| | - Cuiping Jiang
- School of Traditional Chinese Medicine, Southern Medical University, 1838 North Guangzhou Avenue, Guangzhou 510515, China
| | - Li Liu
- School of Traditional Chinese Medicine, Southern Medical University, 1838 North Guangzhou Avenue, Guangzhou 510515, China
| | - Qun Shen
- School of Traditional Chinese Medicine, Southern Medical University, 1838 North Guangzhou Avenue, Guangzhou 510515, China
| | - Hongxia Zhu
- School of Traditional Chinese Medicine, Southern Medical University, 1838 North Guangzhou Avenue, Guangzhou 510515, China
| | - Qiang Liu
- School of Traditional Chinese Medicine, Southern Medical University, 1838 North Guangzhou Avenue, Guangzhou 510515, China
| |
Collapse
|
3
|
Pham QD, Biatry B, Grégoire S, Topgaard D, Sparr E. Solubility of Foreign Molecules in Stratum Corneum Brick and Mortar Structure. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:2347-2357. [PMID: 36716111 PMCID: PMC9933541 DOI: 10.1021/acs.langmuir.2c03092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Revised: 01/12/2023] [Indexed: 06/18/2023]
Abstract
The barrier function of the skin is mainly assured by its outermost layer, stratum corneum (SC). One key aspect in predicting dermal drug delivery and in safety assessment of skin exposure to chemicals is the need to determine the amount of chemical that is taken up into the SC. We here present a strategy that allows for direct measures of the amount of various solid chemicals that can be dissolved in the SC in any environmental relative humidity (RH). A main advantage of the presented method is that it distinguishes between molecules that are dissolved within the SC and molecules that are not dissolved but might be present at, for example, the skin surface. In addition, the method allows for studies of uptake of hydrophobic chemicals without the need to use organic solvents. The strategy relies on the differences in the molecular properties of the added molecules in the dissolved and the excess states, employing detection methods that act as a dynamic filter to spot only one of the fractions, either the dissolved molecules or the excess solid molecules. By measuring the solubility in SC and delipidized SC at the same RHs, the same method can be used to estimate the distribution of the added chemical between the extracellular lipids and corneocytes at different hydration conditions. The solubility in porcine SC is shown to vary with hydration, which has implications for the molecular uptake and transport across the skin. The findings highlight the importance of assessing the chemical uptake at hydration conditions relevant to the specific applications. The methodology presented in this study can also be generalized to study the solubility and partitioning of chemicals in other heterogeneous materials with complex composition and structure.
Collapse
Affiliation(s)
- Quoc Dat Pham
- Division
of Physical Chemistry, Chemistry Department, Lund University, P.O. Box 124, 22100Lund, Sweden
- Gillette
Reading Innovation Centre, 460 Basingstoke Road, ReadingRG2 0QE, Berkshire, U.K.
| | - Bruno Biatry
- L’Oréal
Research & Innovation, 1, avenue Eugène Schueller, 93601Aulnay sous Bois, France
| | - Sébastien Grégoire
- L’Oréal
Research & Innovation, 1, avenue Eugène Schueller, 93601Aulnay sous Bois, France
| | - Daniel Topgaard
- Division
of Physical Chemistry, Chemistry Department, Lund University, P.O. Box 124, 22100Lund, Sweden
| | - Emma Sparr
- Division
of Physical Chemistry, Chemistry Department, Lund University, P.O. Box 124, 22100Lund, Sweden
| |
Collapse
|
4
|
Zhang T, Peng X, Li F, Toufouki S, Yao S. Risk-focused investigation on ionic liquids against their applied background in transdermal delivery. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.118770] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
|
5
|
Mosquera Narvaez LE, Ferreira LMDMC, Sanches S, Alesa Gyles D, Silva-Júnior JOC, Ribeiro Costa RM. A Review of Potential Use of Amazonian Oils in the Synthesis of Organogels for Cosmetic Application. Molecules 2022; 27:molecules27092733. [PMID: 35566084 PMCID: PMC9100349 DOI: 10.3390/molecules27092733] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 11/26/2021] [Accepted: 12/14/2021] [Indexed: 02/01/2023] Open
Abstract
New strategies for the delivery of bioactives in the deeper layers of the skin have been studied in recent years, using mainly natural ingredients. Among the strategies are organogels as a promising tool to load bioactives with different physicochemical characteristics, using vegetable oils. Studies have shown satisfactory skin permeation, good physicochemical stability mainly due to its three-dimensional structure, and controlled release using vegetable oils and low-molecular-weight organogelators. Within the universe of natural ingredients, vegetable oils, especially those from the Amazon, have a series of benefits and characteristics that make them unique compared to conventional oils. Several studies have shown that the use of Amazonian oils brings a series of benefits to the skin, among which are an emollient, moisturizing, and nourishing effect. This work shows a compilation of the main Amazonian oils and their nutraceutical and physicochemical characteristics together with the minority polar components, related to health benefits, and their possible effects on the synthesis of organogels for cosmetic purposes.
Collapse
Affiliation(s)
- Luis Eduardo Mosquera Narvaez
- Laboratory of Pharmaceutical Nanotechnology, College of Pharmacy, Federal University of Pará, Belém 66075-110, Brazil; (L.E.M.N.); (L.M.d.M.C.F.); (S.S.)
| | | | - Suellen Sanches
- Laboratory of Pharmaceutical Nanotechnology, College of Pharmacy, Federal University of Pará, Belém 66075-110, Brazil; (L.E.M.N.); (L.M.d.M.C.F.); (S.S.)
| | - Desireé Alesa Gyles
- Jamaica College of Health Sciences, School of Pharmacy, University of Technology, 237 Old Hope Road, Kinston 6, Jamaica;
| | | | - Roseane Maria Ribeiro Costa
- Laboratory of Pharmaceutical Nanotechnology, College of Pharmacy, Federal University of Pará, Belém 66075-110, Brazil; (L.E.M.N.); (L.M.d.M.C.F.); (S.S.)
- Correspondence: ; Tel.: +55-91-3201-7203
| |
Collapse
|
6
|
Elucidating Pathway and Anesthetic Mechanism of Action of Clove Oil Nanoformulations in Fish. Pharmaceutics 2022; 14:pharmaceutics14050919. [PMID: 35631505 PMCID: PMC9147060 DOI: 10.3390/pharmaceutics14050919] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Revised: 04/15/2022] [Accepted: 04/20/2022] [Indexed: 02/01/2023] Open
Abstract
Clove oil (CO), an essential oil of Syzygium aromaticum, has been reported as an anesthetic for many fish species. However, its insoluble properties require a suitable delivery system for its application. In the present study, nanoformulations of CO as a nanoemulsion (CO-NE), a self-microemulsifying drug-delivery system (CO-SMEDDS), and a self-nanoemulsifying drug-delivery system (CO-SNEDDS) were prepared for delivering CO. Zebrafish were used as a fish model to investigate oil pathways. The result shows fluorescence spots of fluorescence-labeled CO accumulate on the gills, skin, and brain. All CO nanoformulations significantly increased penetration flux compared to CO ethanolic solution. Investigation of the anesthetic mechanism of action using a rat brain γ-aminobutyric acid subtype A (GABAA) receptor-binding test demonstrates that CO and its major compound, eugenol, modulate [3H]muscimol binding. CO-NE exhibited a concentration-dependent binding activity with an EC50 value of 175 µg/mL, significantly higher than CO solution in dimethyl sulfoxide. In conclusion, CO enters the fish through the skin and gills. The anesthetic mechanism of action of CO is based on modulation of [3H] muscimol binding to GABAA receptors. Among three nanoformulations tested, CO-NE is the most effective at increasing permeability and enhancing the receptor-binding activity of the oil.
Collapse
|
7
|
Kis N, Gunnarsson M, Berkó S, Sparr E. The effects of glycols on molecular mobility, structure, and permeability in stratum corneum. J Control Release 2022; 343:755-764. [PMID: 35150813 DOI: 10.1016/j.jconrel.2022.02.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 01/28/2022] [Accepted: 02/07/2022] [Indexed: 11/26/2022]
Abstract
The skin provides an attractive alternative to the conventional drug administration routes. Still, it comes with challenges as the upper layer of the skin, the stratum corneum (SC), provides an efficient barrier against permeation of most compounds. One way to overcome the skin barrier is to apply chemical permeation enhancers, which can modify the SC structure. In this paper, we investigated the molecular effect of three different types of glycols in SC: dipropylene glycol (diPG), propylene glycol (PG), and butylene glycol (BG). The aim is to understand how these molecules influence the molecular mobility and structure of the SC components, and to relate the molecular effects to the efficiency of these molecules as permeation enhancers. We used complementary experimental techniques, including natural abundance 13C NMR spectroscopy and wide-angle X-ray diffraction to characterize the molecular consequences of these compounds at different doses in SC at 97% RH humidity and 32 °C. In addition, we study the permeation enhancing effects of the same glycols in comparable conditions using Raman spectroscopy. Based on the results from NMR, we conclude that all three glycols cause increased mobility in SC lipids, and that the addition of glycols has an effect on the keratin filaments in similar manner as Natural Moisturizing Factor (NMF). The highest mobility of both lipids and amino acids can be reached with BG, which is followed by PG. It is also shown that one reaches an apparent saturation level for all three chemicals in SC, after which increased addition of the compound does not lead to further increase in the mobility of SC lipids or protein components. The examination with Raman mapping show that BG and PG give a significant permeation enhancement as compared to SC without any added glycol at corresponding conditions. Finally, we observe a non-monotonic response in permeation enhancement with respect to the concentration of glycols, where the highest concentration does not give the highest permeation. This is explained by the dehydration effects at highest glycol concentrations. In summary, we find a good correlation between the molecular effects of glycols on the SC lipid and protein mobility, and macroscopic permeation enhances of the same molecules.
Collapse
Affiliation(s)
- Nikolett Kis
- Institute of Pharmaceutical Technology and Regulatory Affairs, Faculty of Pharmacy, University of Szeged, 6720 Szeged, Hungary.
| | - Maria Gunnarsson
- Division of Physical Chemistry, Chemistry Department, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden.
| | - Szilvia Berkó
- Institute of Pharmaceutical Technology and Regulatory Affairs, Faculty of Pharmacy, University of Szeged, 6720 Szeged, Hungary.
| | - Emma Sparr
- Division of Physical Chemistry, Chemistry Department, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden.
| |
Collapse
|
8
|
Pham QD, Gregoire S, Biatry B, Cassin G, Topgaard D, Sparr E. Skin hydration as a tool to control the distribution and molecular effects of intermediate polarity compounds in intact stratum corneum. J Colloid Interface Sci 2021; 603:874-885. [PMID: 34246090 DOI: 10.1016/j.jcis.2021.06.097] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 06/07/2021] [Accepted: 06/15/2021] [Indexed: 01/02/2023]
Abstract
The barrier function of the skin is mainly assured by its outermost layer, stratum corneum (SC), which consists of dead keratin-filled cells embedded in a lipid matrix. The skin is daily exposed to an environment with changing conditions in terms of hydration and different chemicals. Here we investigate how a molecule that has reasonable solubility in both hydrophobic and hydrophilic environments can be directed to certain regions in SC by changing the skin hydration. We use 1,2,3-trimethoxy propane (TMP) as a model substance and solid-state NMR on natural abundance 13C to obtain atomically resolved information on the molecular dynamics of TMP as well as SC lipid and protein components at varying hydration conditions. Upon dehydration, TMP redistributes from the hydrophilic corneocytes to the hydrophobic SC lipid regions. In this way, TMP can act to prevent the fluid-solid lipid transition in drying conditions and be present in the corneocytes in more humid conditions. Hydration can thereby be used as a switch to control the location and action of TMP or similar compounds in complex materials like SC. The general principles described here can also have impact on other applications including lipid-based formulations in food, drug delivery and cosmetics.
Collapse
Affiliation(s)
- Quoc Dat Pham
- Division of Physical Chemistry, Chemistry Department, Lund University, P.O. Box 124, 22100 Lund, Sweden; Department of Food Technology, Lund University, P.O. Box 124, 22100 Lund, Sweden; Product Design, McNeil AB, Box 941, 25109, Helsingborg, Sweden.
| | - Sebastien Gregoire
- L'Oreal Research & Innovation, 1, avenue Eugène Schueller, 93601 Aulnay-sous- Bois, France
| | - Bruno Biatry
- L'Oreal Research & Innovation, 1, avenue Eugène Schueller, 93601 Aulnay-sous- Bois, France
| | - Guillaume Cassin
- L'Oreal Research & Innovation, 1, avenue Eugène Schueller, 93601 Aulnay-sous- Bois, France
| | - Daniel Topgaard
- Division of Physical Chemistry, Chemistry Department, Lund University, P.O. Box 124, 22100 Lund, Sweden
| | - Emma Sparr
- Division of Physical Chemistry, Chemistry Department, Lund University, P.O. Box 124, 22100 Lund, Sweden
| |
Collapse
|
9
|
Nováčková A, Sagrafena I, Pullmannová P, Paraskevopoulos G, Dwivedi A, Mazumder A, Růžičková K, Slepička P, Zbytovská J, Vávrová K. Acidic pH Is Required for the Multilamellar Assembly of Skin Barrier Lipids In Vitro. J Invest Dermatol 2021; 141:1915-1921.e4. [PMID: 33675786 DOI: 10.1016/j.jid.2021.02.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 02/18/2021] [Accepted: 02/23/2021] [Indexed: 11/19/2022]
Abstract
Lipid membrane remodeling belongs to the most fundamental processes in the body. The skin barrier lipids, which are ceramide dominant and highly rigid, must attain an unusual multilamellar nanostructure with long periodicity to restrict water loss and prevent the entry of potentially harmful environmental factors. Our data suggest that the skin acid mantle, apart from regulating enzyme activities and keeping away pathogens, may also be a prerequisite for the multilamellar assembly of the skin barrier lipids. Atomic force microscopy on monolayers composed of synthetic or human stratum corneum lipids showed multilayer formation (approximately 10-nm step height) in an acidic but not in a neutral environment. X-ray diffraction, Fourier transform infrared spectroscopy, and permeability studies showed markedly altered lipid nanostructure and increased water loss at neutral pH compared with that at acidic pH. These findings are consistent with the data on the altered organization of skin lipids and increased transepidermal water loss under conditions such as inadequate skin acidification, for example, in neonates, the elderly, and patients with atopic dermatitis.
Collapse
Affiliation(s)
- Anna Nováčková
- Faculty of Pharmacy in Hradec Králové, Charles University, Hradec Králové, Czech Republic
| | - Irene Sagrafena
- Faculty of Pharmacy in Hradec Králové, Charles University, Hradec Králové, Czech Republic
| | - Petra Pullmannová
- Faculty of Pharmacy in Hradec Králové, Charles University, Hradec Králové, Czech Republic
| | | | - Anupma Dwivedi
- Faculty of Pharmacy in Hradec Králové, Charles University, Hradec Králové, Czech Republic
| | - Anisha Mazumder
- Faculty of Pharmacy in Hradec Králové, Charles University, Hradec Králové, Czech Republic
| | - Karolína Růžičková
- Faculty of Pharmacy in Hradec Králové, Charles University, Hradec Králové, Czech Republic
| | - Petr Slepička
- Faculty of Chemical Technology, University of Chemistry and Technology Prague, Prague, Czech Republic
| | - Jarmila Zbytovská
- Faculty of Pharmacy in Hradec Králové, Charles University, Hradec Králové, Czech Republic; Faculty of Chemical Technology, University of Chemistry and Technology Prague, Prague, Czech Republic
| | - Kateřina Vávrová
- Faculty of Pharmacy in Hradec Králové, Charles University, Hradec Králové, Czech Republic.
| |
Collapse
|
10
|
Mojumdar EH, Sparr E. The effect of pH and salt on the molecular structure and dynamics of the skin. Colloids Surf B Biointerfaces 2021; 198:111476. [DOI: 10.1016/j.colsurfb.2020.111476] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 11/08/2020] [Accepted: 11/09/2020] [Indexed: 01/17/2023]
|
11
|
Liu Y, Lunter DJ. Tracking heavy-water-incorporated confocal Raman spectroscopy for evaluating the effects of PEGylated emulsifiers on skin barrier. JOURNAL OF BIOPHOTONICS 2020; 13:e202000286. [PMID: 32975040 DOI: 10.1002/jbio.202000286] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 09/22/2020] [Accepted: 09/22/2020] [Indexed: 06/11/2023]
Abstract
The class of PEGylated emulsifiers finds broad application in the pharmaceutical and cosmetic industry. We target on one of the categories of polyethylene glycol (PEG) alkyl ethers with different lipophilic and hydrophilic chain length and aim to examine their effects on the skin comprehensively. In this study, we employed confocal Raman spectroscopy for skin depth profiling and imaging. A unique probe of heavy water (D2 O) was incorporated, which can be tracked percutaneously and simultaneously monitor the effects caused by emulsifiers. According to the results, most of the PEGylated emulsifiers caused changes in skin lipid content/organization and induced the alteration in relative water content/hydrogen bonding structure. The results obtained from the depth profiling analysis provided the possibility to estimate the least penetration depth of emulsifiers. Among them, PEG-20 ethers displayed the most penetration ability. Meanwhile, it is interesting to find that the treatment of emulsifiers also affected the spatial distribution of D2 O whose differences were in line with the molecular skin variations. In particular, the isotopic H/D substitution in the skin was highlighted in detail. This result supports the possibility to use D2 O as an excellent and cost-effective probe to evaluate the skin barrier function.
Collapse
Affiliation(s)
- Yali Liu
- Department of Pharmaceutical Technology, Faculty of Science, Eberhard Karls Universität Tübingen, Tuebingen, Germany
| | - Dominique Jasmin Lunter
- Department of Pharmaceutical Technology, Faculty of Science, Eberhard Karls Universität Tübingen, Tuebingen, Germany
| |
Collapse
|
12
|
Engberg O, Kováčik A, Pullmannová P, Juhaščik M, Opálka L, Huster D, Vávrová K. The Sphingosine and Acyl Chains of Ceramide [NS] Show Very Different Structure and Dynamics That Challenge Our Understanding of the Skin Barrier. Angew Chem Int Ed Engl 2020; 59:17383-17387. [PMID: 32515145 PMCID: PMC7540555 DOI: 10.1002/anie.202003375] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 05/22/2020] [Indexed: 12/28/2022]
Abstract
The lipid phase of the uppermost human skin layer is thought to comprise highly rigid lipids in an orthorhombic phase state to protect the body against the environment. By synthesizing sphingosine-d28 deuterated N-lignoceroyl-d-erythro-sphingosine (ceramide [NS]), we compare the structure and dynamics of both chains of that lipid in biologically relevant mixtures using X-ray diffraction, 2 H NMR analysis, and infrared spectroscopy. Our results reveal a substantial fraction of sphingosine chains in a fluid and dynamic phase state at physiological temperature. These findings prompt revision of our current understanding of the skin lipid barrier, where an extended ceramide [NS] conformation is preferred and a possible domain structure is proposed. Mobile lipid chains may be crucial for skin elasticity and the translocation of physiologically important molecules.
Collapse
Affiliation(s)
- Oskar Engberg
- Institute of Medical Physics and BiophysicsUniversity of LeipzigHärtelstr. 16–1804275LeipzigGermany
| | - Andrej Kováčik
- Skin Barrier Research GroupFaculty of Pharmacy in Hradec KrálovéCharles UniversityAkademika Heyrovského 120350005Hradec KrálovéCzech Republic
| | - Petra Pullmannová
- Skin Barrier Research GroupFaculty of Pharmacy in Hradec KrálovéCharles UniversityAkademika Heyrovského 120350005Hradec KrálovéCzech Republic
| | - Martin Juhaščik
- Skin Barrier Research GroupFaculty of Pharmacy in Hradec KrálovéCharles UniversityAkademika Heyrovského 120350005Hradec KrálovéCzech Republic
| | - Lukáš Opálka
- Skin Barrier Research GroupFaculty of Pharmacy in Hradec KrálovéCharles UniversityAkademika Heyrovského 120350005Hradec KrálovéCzech Republic
| | - Daniel Huster
- Institute of Medical Physics and BiophysicsUniversity of LeipzigHärtelstr. 16–1804275LeipzigGermany
- Department of Chemical ScienceTata Institute of Fundamental ResearchDr. Homi Bhabha Road, ColabaMumbai400 005India
| | - Kateřina Vávrová
- Skin Barrier Research GroupFaculty of Pharmacy in Hradec KrálovéCharles UniversityAkademika Heyrovského 120350005Hradec KrálovéCzech Republic
| |
Collapse
|
13
|
Engberg O, Kováčik A, Pullmannová P, Juhaščik M, Opálka L, Huster D, Vávrová K. Die unterschiedliche Struktur und Dynamik der Sphingosin‐ und Acylketten von Ceramid [NS] verändern unser Verständnis der Struktur der Hautbarriere. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202003375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Oskar Engberg
- Institut für Medizinische Physik und Biophysik Universität Leipzig Härtelstraße 16–18 04275 Leipzig Deutschland
| | - Andrej Kováčik
- Skin Barrier Research Group Faculty of Pharmacy in Hradec Králové Charles University Akademika Heyrovského 1203 50005 Hradec Králové Czech Republi
| | - Petra Pullmannová
- Skin Barrier Research Group Faculty of Pharmacy in Hradec Králové Charles University Akademika Heyrovského 1203 50005 Hradec Králové Czech Republi
| | - Martin Juhaščik
- Skin Barrier Research Group Faculty of Pharmacy in Hradec Králové Charles University Akademika Heyrovského 1203 50005 Hradec Králové Czech Republi
| | - Lukáš Opálka
- Skin Barrier Research Group Faculty of Pharmacy in Hradec Králové Charles University Akademika Heyrovského 1203 50005 Hradec Králové Czech Republi
| | - Daniel Huster
- Institut für Medizinische Physik und Biophysik Universität Leipzig Härtelstraße 16–18 04275 Leipzig Deutschland
- Department of Chemical Science Tata Institute of Fundamental Research Dr. Homi Bhabha Road, Colaba Mumbai 400 005 Indien
| | - Kateřina Vávrová
- Skin Barrier Research Group Faculty of Pharmacy in Hradec Králové Charles University Akademika Heyrovského 1203 50005 Hradec Králové Czech Republi
| |
Collapse
|
14
|
Hama T, Kouchi A, Watanabe N, Shioya N, Shimoaka T, Hasegawa T. In vivo characterization of the structures of films of a fatty acid and an alcohol adsorbed on the skin surface. Biophys Chem 2020; 266:106459. [PMID: 32835910 DOI: 10.1016/j.bpc.2020.106459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 08/13/2020] [Accepted: 08/14/2020] [Indexed: 11/17/2022]
Abstract
An in vivo analysis of stearyl alcohol and stearic acid films on the skin surface using polarized infrared-external reflection spectroscopy revealed that whether the sample molecules adopt an energetically stable conformation and orientation strongly depends on the molecular functionalities and sample preparation conditions. For stearic acid, even the difference in solute concentration between 0.1 and 0.5 wt% results in a different molecular conformation and orientation. This illustrates that the molecular organization of the adsorbate on the skin surface is sensitively determined by the kinetics of the sample film growth, not by the simple thermodynamic equilibrium with the skin temperature.
Collapse
Affiliation(s)
- Tetsuya Hama
- Komaba Institute for Science, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo 153-8902, Japan; Department of Basic Science, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo 153-8902, Japan.
| | - Akira Kouchi
- Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan
| | - Naoki Watanabe
- Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan
| | - Nobutaka Shioya
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Takafumi Shimoaka
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Takeshi Hasegawa
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| |
Collapse
|
15
|
Kilo S, Wick J, Mini Vijayan S, Göen T, Horch RE, Ludolph I, Drexler H. Impact of physiologically relevant temperatures on dermal absorption of active substances - an ex-vivo study in human skin. Toxicol In Vitro 2020; 68:104954. [PMID: 32738276 DOI: 10.1016/j.tiv.2020.104954] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 07/08/2020] [Accepted: 07/27/2020] [Indexed: 11/18/2022]
Abstract
Skin temperature plays a certain role in the dermal absorption of substances, but the extent and mechanisms of skin temperatures-induced modulation in ranges caused by physiological thermoregulation or environmental conditions are largely unknown. The influence of dermal temperature on the absorption of the model lipophilic compound (anisole) and the model hydrophilic compounds (1,4-dioxane, ethanol) through human skin was investigated at three dermal temperatures (25, 32 and 39 °C) in an ex-vivo diffusion cell model. The substances were applied to the skin and transdermal penetration was monitored. All substances showed temperature dependent variations in their penetration behavior (3 h: 25-39 °C: 202-275% increase in cumulative, transdermally penetrated amounts). The relative differences in absorption in relation to temperature were greatest within 45 min after exposure (25-39 °C: 347-653% rise in cumulated penetration), although absolute amounts absorbed were small (45 min vs. 3 h: 4.5-14.5%). Regardless of blood circulation, skin temperature significantly influences the amount and kinetics of dermal absorption. Substance-dependent, temperature-related changes of the lipid layer order or the porous pathway may facilitate penetration. The early-stage modulation of transdermal penetration indicates transappendageal absorption, which may be relevant for short-term exposures. For both, toxicological evaluation and perfusion cell studies, it is important to consider the thermal influence on absorption or to perform the latter at a standardized temperature (32±1 °C).
Collapse
Affiliation(s)
- S Kilo
- Institute and Out-Patient Clinic of Occupational, Social and Environmental Medicine, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Germany.
| | - J Wick
- Institute and Out-Patient Clinic of Occupational, Social and Environmental Medicine, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Germany
| | - S Mini Vijayan
- Institute and Out-Patient Clinic of Occupational, Social and Environmental Medicine, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Germany
| | - T Göen
- Institute and Out-Patient Clinic of Occupational, Social and Environmental Medicine, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Germany
| | - R E Horch
- Department of Plastic and Hand Surgery, University Hospital of Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Germany
| | - I Ludolph
- Department of Plastic and Hand Surgery, University Hospital of Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Germany
| | - H Drexler
- Institute and Out-Patient Clinic of Occupational, Social and Environmental Medicine, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Germany
| |
Collapse
|
16
|
Pham QD, Carlström G, Lafon O, Sparr E, Topgaard D. Quantification of the amount of mobile components in intact stratum corneum with natural-abundance 13C solid-state NMR. Phys Chem Chem Phys 2020; 22:6572-6583. [PMID: 32159206 DOI: 10.1039/d0cp00079e] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The outermost layer of the skin is the stratum corneum (SC), which is mainly comprised of solid proteins and lipids. Minor amounts of mobile proteins and lipids are crucial for the macroscopic properties of the SC, including softness, elasticity and barrier function. Still this minor number of mobile components are not well characterized in terms of structure or amount. Conventional quantitative direct polarization (Q-DP) 13C solid-state NMR gives signal amplitudes proportional to concentrations, but fails to quantify the SC mobile components because of spectral overlap with the overwhelming signals from the solids. Spectral editing with the INEPT scheme suppresses the signals from solids, but also modulates the amplitudes of the mobile components depending on their values of the transverse relaxation times T2, scalar couplings JCH, and number of covalently bound hydrogens nH. This study describes a quantitative INEPT (Q-INEPT) method relying on systematic variation of the INEPT timing variables to estimate T2, JCH, nH, and amplitude for each of the resolved resonances from the mobile components. Q-INEPT is validated with a series of model systems containing molecules with different hydrophobicity and dynamics. For selected systems where Q-DP is applicable, the results of Q-INEPT and Q-DP are similar with respect to the linearity and uncertainty of the obtained molar ratios. Utilizing a reference compound with known concentration, we quantify the concentrations of mobile lipids and proteins within the mainly solid SC. By melting all lipids at high temperature, we obtain the total lipid concentration. These Q-INEPT results are the first steps towards a quantitative understanding of the relations between mobile component concentrations and SC macroscopic properties.
Collapse
Affiliation(s)
- Quoc Dat Pham
- Division of Physical Chemistry, Chemistry Department, Lund University, Lund, Sweden and Department of Food Technology, Lund University, Lund, Sweden
| | - Göran Carlström
- Centre for Analysis and Synthesis, Department of Chemistry, Lund University, Lund, Sweden
| | - Olivier Lafon
- Univ. Lille, CNRS, Centrale Lille, Univ. Artois, UMR 8181-UCCS-Unité de Catalyse et Chimie du Solide, F-59000 Lille, France and Institut Universitaire de France (IUF), Paris, France
| | - Emma Sparr
- Division of Physical Chemistry, Chemistry Department, Lund University, Lund, Sweden
| | - Daniel Topgaard
- Division of Physical Chemistry, Chemistry Department, Lund University, Lund, Sweden
| |
Collapse
|
17
|
Solvent Effects on Skin Penetration and Spatial Distribution of the Hydrophilic Nitroxide Spin Probe PCA Investigated by EPR. Cell Biochem Biophys 2020; 78:127-137. [PMID: 32303897 PMCID: PMC8557165 DOI: 10.1007/s12013-020-00908-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 03/30/2020] [Indexed: 12/13/2022]
Abstract
Oxidative stress occurs in extrinsic skin aging processes and diseases when the enhanced production of free radicals exceeds the homeostatic antioxidant capacity of the skin. The spin probe, 3-(carboxy)-2,2,5,5-tetramethylpyrrolidin-1-oxyl (PCA), is frequently used to study the cutaneous radical production by electron paramagnetic resonance (EPR) spectroscopy. This approach requires delivering PCA into the skin, yet solvent effects on the skin penetration and spatial distribution of PCA have not been thoroughly investigated. Three solvents of ethanol, phosphate-buffered saline (PBS) and ethanol-PBS (1:1) were studied. For both human and porcine skin ex vivo, the amount of PCA in the stratum corneum (SC) was the lowest when using ethanol and very similar for PBS and ethanol-PBS. The highest amount of PCA in the viable skin layers was detected for ethanol-PBS, yet it only took up less than 5% of the total amount. The majority of PCA was localized in the SC, among which PCA with high mobility was predominantly distributed in the hydrophilic microenvironment of corneocytes and PCA with lower mobility was mainly in the less hydrophilic microenvironment of intercellular skin lipids. A higher ethanol concentration in the solvent could improve the distribution of PCA in the hydrophilic microenvironments of the SC. The results suggest that ethanol-PBS (1:1) is best-suited for delivering most PCA deep into the skin. This work enhances the understanding of solvent effects on the skin penetration and distribution of PCA and supports the utilization of PCA in studying cutaneous radical production.
Collapse
|
18
|
MacDermaid CM, Hall KW, DeVane RH, Klein ML, Fiorin G. Coexistence of Lipid Phases Stabilizes Interstitial Water in the Outer Layer of Mammalian Skin. Biophys J 2020; 118:1588-1601. [PMID: 32101711 DOI: 10.1016/j.bpj.2020.01.044] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 01/20/2020] [Accepted: 01/27/2020] [Indexed: 12/22/2022] Open
Abstract
The lipid matrix in the outer layer of mammalian skin, the stratum corneum, has been previously investigated by multiple biophysical techniques aimed at identifying hydrophilic and lipophilic pathways of permeation. Although consensus is developing over the microscopic structure of the lipid matrix, no molecular-resolution model describes the permeability of all chemical species simultaneously. Using molecular dynamics simulations of a model mixture of skin lipids, the self-assembly of the lipid matrix lamellae has been studied. At higher humidity, the resulting lamellar phase is maintained by partitioning excess water into isolated droplets of controlled size and spatial distribution. The droplets may fuse together to form intralamellar water channels, thereby providing a pathway for the permeation of hydrophilic species. These results reconcile competing data on the outer skin's structure and broaden the scope of molecular-based methods to improve the safety of topical products and to advance transdermal drug delivery.
Collapse
Affiliation(s)
- Christopher M MacDermaid
- Institute for Computational Molecular Science and Temple Materials Institute, Philadelphia, Pennsylvania
| | - Kyle Wm Hall
- Institute for Computational Molecular Science and Temple Materials Institute, Philadelphia, Pennsylvania
| | | | - Michael L Klein
- Institute for Computational Molecular Science and Temple Materials Institute, Philadelphia, Pennsylvania
| | - Giacomo Fiorin
- Institute for Computational Molecular Science and Temple Materials Institute, Philadelphia, Pennsylvania.
| |
Collapse
|
19
|
Mojumdar EH, Grey C, Sparr E. Self-Assembly in Ganglioside‒Phospholipid Systems: The Co-Existence of Vesicles, Micelles, and Discs. Int J Mol Sci 2019; 21:ijms21010056. [PMID: 31861839 PMCID: PMC6982371 DOI: 10.3390/ijms21010056] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Revised: 12/05/2019] [Accepted: 12/16/2019] [Indexed: 02/07/2023] Open
Abstract
Ganglioside lipids have been associated with several physiological processes, including cell signaling. They have also been associated with amyloid aggregation in Parkinson’s and Alzheimer’s disease. In biological systems, gangliosides are present in a mix with other lipid species, and the structure and properties of these mixtures strongly depend on the proportions of the different components. Here, we study self-assembly in model mixtures composed of ganglioside GM1 and a zwitterionic phospholipid, 1,2-Dioleoyl-sn-glycero-3-phosphocholine (DOPC). We characterize the structure and molecular dynamics using a range of complementary techniques, including cryo-TEM, polarization transfer solid state NMR, diffusion NMR, small-angle X-ray scattering (SAXS), dynamic light scattering (DLS), and calorimetry. The main findings are: (1) The lipid acyl chains are more rigid in mixtures containing both lipid species compared to systems that only contain one of the lipids. (2) The system containing DOPC with 10 mol % GM1 contains both vesicles and micelles. (3) At higher GM1 concentrations, the sample is more heterogenous and also contains small disc-like or rod-like structures. Such a co-existence of structures can have a strong impact on the overall properties of the lipid system, including transport, solubilization, and partitioning, which can be crucial to the understanding of the role of gangliosides in biological systems.
Collapse
Affiliation(s)
- Enamul Haque Mojumdar
- Physical Chemistry, Lund University, 221 00 Lund, Sweden
- Correspondence: (E.H.M.); (E.S.); Tel.: +46-46-222-33-32 (E.H.M.); +46-46-222-15-36 (E.S.)
| | - Carl Grey
- Division of Biotechnology, Lund University, 221 00 Lund, Sweden;
| | - Emma Sparr
- Physical Chemistry, Lund University, 221 00 Lund, Sweden
- Correspondence: (E.H.M.); (E.S.); Tel.: +46-46-222-33-32 (E.H.M.); +46-46-222-15-36 (E.S.)
| |
Collapse
|
20
|
Abstract
Skin hydration is a complex process that influences the physical and mechanical properties of skin. Various technologies have emerged over the years to assess this parameter, with the current standard being electrical probe-based instruments. Nevertheless, their inability to provide detailed information has prompted the use of sophisticated spectroscopic and imaging methodologies, which are capable of in-depth skin analysis that includes structural and composition details. Modern imaging and spectroscopic techniques have transformed skin research in the dermatological and cosmetics disciplines, and are now commonly employed in conjunction with traditional methods for comprehensive assessment of both healthy and pathological skin. This article reviews current techniques employed in measuring skin hydration, and gives an account on their principle of operation and applications in skin-related research.
Collapse
|
21
|
Gennari CGM, Selmin F, Minghetti P, Cilurzo F. Medicated Foams and Film Forming Dosage Forms as Tools to Improve the Thermodynamic Activity of Drugs to be Administered Through the Skin. Curr Drug Deliv 2019; 16:461-471. [PMID: 30657040 PMCID: PMC6637090 DOI: 10.2174/1567201816666190118124439] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 01/04/2019] [Accepted: 01/09/2019] [Indexed: 11/22/2022]
Abstract
Medicated foams and film forming systems are dosage forms formulated to undergo a con-trolled metamorphosis when applied on the skin. Indeed, due to the presence of propellant or a particular air-spray foam pump, a liquid can generate foam when applied on the stratum corneum, or a liquid or conventional dosage form can form on the skin a continuous film as a consequence of the solvent evapora-tion. Thanks to these controlled modifications, the drug thermodynamic activity increases favoring the skin penetration and, therefore, the bioavailability with respect to conventional semi-solid and liquid dosage forms. Furthermore, the available clinical data also evidence that these dosage forms improve the patient’s compliance. The main formulative aspects of medicated foams and film forming systems are reviewed with the aim to underline the possible advantages in terms of biopharmaceutical performances and pa-tient’s adherence.
Collapse
Affiliation(s)
- Chiara G M Gennari
- Department of Pharmaceutical Sciences, University of Milan, Via G. Colombo, 71 - 20133 Milan, Italy
| | - Francesca Selmin
- Department of Pharmaceutical Sciences, University of Milan, Via G. Colombo, 71 - 20133 Milan, Italy
| | - Paola Minghetti
- Department of Pharmaceutical Sciences, University of Milan, Via G. Colombo, 71 - 20133 Milan, Italy
| | - Francesco Cilurzo
- Department of Pharmaceutical Sciences, University of Milan, Via G. Colombo, 71 - 20133 Milan, Italy
| |
Collapse
|
22
|
Abstract
AbstractThe outer layer of the skin, stratum corneum (SC) is an efficient transport barrier and it tolerates mechanical deformation. At physiological conditions, the majority of SC lipids are solid, while the presence of a small amount of fluid lipids is considered crucial for SC barrier and material properties. Here we use solid-state and diffusion nuclear magnetic resonance to characterize the composition and molecular dynamics of the fluid lipid fraction in SC model lipids, focusing on the role of the essential SC lipid CER EOS, which is a ceramide esterified omega-hydroxy sphingosine linoleate with very long chain. We show that both rigid and mobile structures are present within the same CER EOS molecule, and that the linoleate segments undergo fast isotropic reorientation while exhibiting extraordinarily slow self-diffusion. The characterization of this unusual self-assembly in SC lipids provides deepened insight into the molecular arrangement in the SC extracellular lipid matrix and the role of CER EOS linoleate in the healthy and diseased skin.
Collapse
|
23
|
Soltanipoor M, Stilla T, Riethmüller C, Thyssen JP, Sluiter JK, Rustemeyer T, Fischer TW, Kezic S, Angelova-Fischer I. Specific barrier response profiles after experimentally induced skin irritation in vivo. Contact Dermatitis 2018; 79:59-66. [PMID: 29607504 PMCID: PMC6099430 DOI: 10.1111/cod.12981] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 01/23/2018] [Accepted: 01/24/2018] [Indexed: 12/25/2022]
Abstract
Background Recently, natural moisturizing factors (NMFs) and corneocyte surface topography were suggested as biomarkers for irritant dermatitis. Objectives To investigate how exposure to different irritants influences corneocyte surface topography, NMF levels and the barrier function of human skin in vivo. Methods Eight healthy adult volunteers were exposed to aqueous solutions of 60% n‐propanol, 0.5% sodium lauryl sulfate (SLS), 0.15% sodium hydroxide, and 2.0% acetic acid, and distilled water, in a repeated irritation test over a period of 96 hours. Erythema, transepidermal water loss (TEWL), skin hydration, the dermal texture index (DTI) and NMF levels were measured at baseline, and after 24 and 96 hours. Results SLS and sodium hydroxide had the most pronounced effects on erythema and TEWL. Although n‐propanol caused only slight changes in TEWL and erythema, it showed pronounced effects on skin hydration, NMF levels, and the DTI. NMF was the only parameter that was significantly altered by all investigated irritants. The changes in the DTI were inversely associated with NMF levels and skin hydration. Conclusion Skin barrier impairment and the inflammatory response are irritant‐specific, emphasizing the need for a multiparametric approach to the study of skin irritation. NMF levels seem to be the most sensitive parameter in detecting irritant‐induced skin barrier alterations.
Collapse
Affiliation(s)
- Maryam Soltanipoor
- Coronel Institute of Occupational Health, Academic Medical Centre, Amsterdam Public Health Research Institute, University of Amsterdam, Amsterdam, The Netherlands.,Department of Dermatology, VU University Medical Centre, Amsterdam, The Netherlands
| | - Tasja Stilla
- Department of Dermatology, University of Lübeck, Lübeck, Germany
| | - Christoph Riethmüller
- Centre for Nanotechnology, Serend-ip GmbH, Centre for Nanotechnology, Münster, Germany
| | - Jacob P Thyssen
- National Allergy Research Centre, Department of Dermatology and Allergy, Copenhagen University Hospital Herlev-Gentofte, University of Copenhagen, Hellerup, Denmark
| | - Judith K Sluiter
- Coronel Institute of Occupational Health, Academic Medical Centre, Amsterdam Public Health Research Institute, University of Amsterdam, Amsterdam, The Netherlands
| | - Thomas Rustemeyer
- Department of Dermatology, VU University Medical Centre, Amsterdam, The Netherlands
| | - Tobias W Fischer
- Department of Dermatology, University of Lübeck, Lübeck, Germany
| | - Sanja Kezic
- Coronel Institute of Occupational Health, Academic Medical Centre, Amsterdam Public Health Research Institute, University of Amsterdam, Amsterdam, The Netherlands
| | | |
Collapse
|
24
|
|
25
|
Azadi-Chegeni F, Schiphorst C, Pandit A. In vivo NMR as a tool for probing molecular structure and dynamics in intact Chlamydomonas reinhardtii cells. PHOTOSYNTHESIS RESEARCH 2018; 135:227-237. [PMID: 28646418 PMCID: PMC5783995 DOI: 10.1007/s11120-017-0412-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 06/07/2017] [Indexed: 06/14/2023]
Abstract
We report the application of NMR dynamic spectral editing for probing the structure and dynamics of molecular constituents in fresh, intact cells and in freshly prepared thylakoid membranes of Chlamydomonas reinhardtii (Cr.) green algae. For isotope labeling, wild-type Cr. cells were grown on 13C acetate-enriched minimal medium. 1D 13C J-coupling based and dipolar-based MAS NMR spectra were applied to distinguish 13C resonances of different molecular components. 1D spectra were recorded over a physiological temperature range, and whole-cell spectra were compared to those taken from thylakoid membranes, evaluating their composition and dynamics. A theoretical model for NMR polarization transfer was used to simulate the relative intensities of direct, J-coupling, and dipolar-based polarization from which the degree of lipid segmental order and rotational dynamics of the lipid acyl chains were estimated. We observe that thylakoid lipid signals dominate the lipid spectral profile of whole algae cells, demonstrating that with our novel method, thylakoid membrane characteristics can be detected with atomistic precision inside intact photosynthetic cells. The experimental procedure is rapid and applicable to fresh cell cultures, and could be used as an original approach for detecting chemical profiles, and molecular structure and dynamics of photosynthetic membranes in vivo in functional states.
Collapse
Affiliation(s)
- Fatemeh Azadi-Chegeni
- Department of Solid State NMR, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333CC, Leiden, The Netherlands
| | - Christo Schiphorst
- Department of Solid State NMR, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333CC, Leiden, The Netherlands
- Department of Biotechnology, University of Verona, Verona, Italy
| | - Anjali Pandit
- Department of Solid State NMR, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333CC, Leiden, The Netherlands.
| |
Collapse
|
26
|
Mojumdar EH, Pham QD, Topgaard D, Sparr E. Skin hydration: interplay between molecular dynamics, structure and water uptake in the stratum corneum. Sci Rep 2017; 7:15712. [PMID: 29146971 PMCID: PMC5691061 DOI: 10.1038/s41598-017-15921-5] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 10/27/2017] [Indexed: 12/24/2022] Open
Abstract
Hydration is a key aspect of the skin that influences its physical and mechanical properties. Here, we investigate the interplay between molecular and macroscopic properties of the outer skin layer - the stratum corneum (SC) and how this varies with hydration. It is shown that hydration leads to changes in the molecular arrangement of the peptides in the keratin filaments as well as dynamics of C-H bond reorientation of amino acids in the protruding terminals of keratin protein within the SC. The changes in molecular structure and dynamics occur at a threshold hydration corresponding to ca. 85% relative humidity (RH). The abrupt changes in SC molecular properties coincide with changes in SC macroscopic swelling properties as well as mechanical properties in the SC. The flexible terminals at the solid keratin filaments can be compared to flexible polymer brushes in colloidal systems, creating long-range repulsion and extensive swelling in water. We further show that the addition of urea to the SC at reduced RH leads to similar molecular and macroscopic responses as the increase in RH for SC without urea. The findings provide new molecular insights to deepen the understanding of how intermediate filament organization responds to changes in the surrounding environment.
Collapse
Affiliation(s)
- Enamul Haque Mojumdar
- Division of Physical Chemistry, Center for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, SE-22100, Lund, Sweden.
| | - Quoc Dat Pham
- Division of Physical Chemistry, Center for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, SE-22100, Lund, Sweden
| | - Daniel Topgaard
- Division of Physical Chemistry, Center for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, SE-22100, Lund, Sweden
| | - Emma Sparr
- Division of Physical Chemistry, Center for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, SE-22100, Lund, Sweden.
| |
Collapse
|
27
|
Paz Ramos A, Gooris G, Bouwstra J, Lafleur M. Evidence of hydrocarbon nanodrops in highly ordered stratum corneum model membranes. J Lipid Res 2017; 59:137-143. [PMID: 29092959 DOI: 10.1194/jlr.m080432] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 10/26/2017] [Indexed: 01/18/2023] Open
Abstract
The stratum corneum (SC), the top layer of skin, dictates the rate of both water loss through the skin and absorption of exogenous molecules into the body. The crystalline organization of the lipids in the SC is believed to be a key feature associated with the very limited permeability of the skin. In this work, we characterized the organization of SC lipid models that include, as in native SC, cholesterol, a series of FFAs (saturated with C16-C24 chains), as well as a ceramide bearing an oleate chain-linked to a very long saturated acyl chain [N-melissoyl-oleoyloxy hexacosanoyl-D-erythro-sphingosine (Cer EOS)]. The latter is reported to be essential for the native SC lipid organization. Our 2H-NMR, infrared, and Raman spectroscopy data reveal that Cer EOS leads to the formation of highly disordered liquid domains in a solid/crystalline matrix. The lipid organization imposes steric constraint on Cer EOS oleate chains in such a way that these hydrocarbon nanodroplets remain in the liquid state down to -30°C. These findings modify the structural description of the SC substantially and propose a novel role of Cer EOS, as this lipid is a strong modulator of SC solid/liquid balance.
Collapse
Affiliation(s)
- Adrian Paz Ramos
- Department of Chemistry, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Gert Gooris
- Department of Drug Delivery Technology, Leiden Academic Centre for Drug Research, 2333 CC Leiden, The Netherlands
| | - Joke Bouwstra
- Department of Drug Delivery Technology, Leiden Academic Centre for Drug Research, 2333 CC Leiden, The Netherlands
| | - Michel Lafleur
- Department of Chemistry, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| |
Collapse
|
28
|
Stahlberg S, Eichner A, Sonnenberger S, Kováčik A, Lange S, Schmitt T, Demé B, Hauß T, Dobner B, Neubert RHH, Huster D. Influence of a Novel Dimeric Ceramide Molecule on the Nanostructure and Thermotropic Phase Behavior of a Stratum Corneum Model Mixture. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:9211-9221. [PMID: 28819979 DOI: 10.1021/acs.langmuir.7b01227] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The stratum corneum (SC) is the outermost layer of the skin and is composed of a multilayered assembly of mostly ceramids (Cer), free fatty acids, cholesterol (Chol), and cholesterol sulfate (Chol-S). Because of the tight packing of these lipids, the SC features unique barrier properties defending the skin from environmental influences. Under pathological conditions, where the skin barrier function is compromised, topical application of molecules that rigidify the SC may lead to a restored barrier function. To this end, molecules are required that incorporate into the SC and bring back the original rigidity of the skin barrier. Here, we investigated the influence of a novel dimeric ceramide (dim-Cer) molecule designed to feature a long, rigid hydrocarbon chain ideally suited to forming an orthorhombic lipid phase. The influence of this molecules on the thermotropic phase behavior of a SC mixture consisting of Cer[AP18] (55 wt %), cholesterol (Chol, 25 wt %), steric acid (SA, 15 wt %), and cholesterol sulfate (Chol-S, 5 wt %) was studied using a combination of neutron diffraction and 2H NMR spectroscopy. These methods provide detailed insights into the packing properties of the lipids in the SC model mixture. Dim-Cer remains in an all-trans state of the membrane-spanning lipid chain at all investigated temperatures, but the influence on the phase behavior of the other lipids in the mixture is marginal. Biophysical experiments are complemented by permeability measurements in model membranes and human skin. The latter, however, indicates that dim-Cer only partially provides the desired effect on membrane permeability, necessitating further optimization of its structure for medical applications.
Collapse
Affiliation(s)
- Sören Stahlberg
- Institute for Medical Physics and Biophysics, Leipzig University , Leipzig, Germany
| | - Adina Eichner
- Institute of Pharmacy and #Institute of Applied Dermatopharmacy, Martin Luther University Halle-Wittenberg , Halle (Saale), Germany
| | - Stefan Sonnenberger
- Institute for Medical Physics and Biophysics, Leipzig University , Leipzig, Germany
- Institute of Pharmacy and #Institute of Applied Dermatopharmacy, Martin Luther University Halle-Wittenberg , Halle (Saale), Germany
| | - Andrej Kováčik
- Institute for Medical Physics and Biophysics, Leipzig University , Leipzig, Germany
- Skin Barrier Research Group, Faculty of Pharmacy in Hradec Králové, Charles University , Akademika Heyrovského 1203, 50005 Hradec Králové, Czech Republic
| | - Stefan Lange
- Institute of Pharmacy and #Institute of Applied Dermatopharmacy, Martin Luther University Halle-Wittenberg , Halle (Saale), Germany
| | - Thomas Schmitt
- Institute of Pharmacy and #Institute of Applied Dermatopharmacy, Martin Luther University Halle-Wittenberg , Halle (Saale), Germany
- Institute of Soft Matter and Functional Materials, Helmholtz-Zentrum Berlin für Materialien und Energie , Berlin, Germany
| | - Bruno Demé
- Institute Laue-Langevin (ILL) , Grenoble, France
| | - Thomas Hauß
- Institute of Soft Matter and Functional Materials, Helmholtz-Zentrum Berlin für Materialien und Energie , Berlin, Germany
| | - Bodo Dobner
- Institute of Pharmacy and #Institute of Applied Dermatopharmacy, Martin Luther University Halle-Wittenberg , Halle (Saale), Germany
| | - Reinhard H H Neubert
- Institute of Pharmacy and #Institute of Applied Dermatopharmacy, Martin Luther University Halle-Wittenberg , Halle (Saale), Germany
| | - Daniel Huster
- Institute for Medical Physics and Biophysics, Leipzig University , Leipzig, Germany
| |
Collapse
|
29
|
Choe C, Schleusener J, Lademann J, Darvin ME. In vivo confocal Raman microscopic determination of depth profiles of the stratum corneum lipid organization influenced by application of various oils. J Dermatol Sci 2017; 87:183-191. [PMID: 28522139 DOI: 10.1016/j.jdermsci.2017.04.016] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 04/05/2017] [Accepted: 04/28/2017] [Indexed: 11/16/2022]
Abstract
BACKGROUND The intercellular lipids (ICL) of stratum corneum (SC) play an important role in maintaining the skin barrier function. The lateral and lamellar packing order of ICL in SC is not homogenous, but rather depth-dependent. OBJECTIVE This study aimed to analyze the influence of the topically applied mineral-derived (paraffin and petrolatum) and plant-derived (almond oil and jojoba oil) oils on the depth-dependent ICL profile ordering of the SC in vivo. METHOD Confocal Raman microscopy (CRM), a unique tool to analyze the depth profile of the ICL structure non-invasively, is employed to investigate the interaction between oils and human SC in vivo. RESULTS The results show that the response of SC to oils' permeation varies in the depths. All oils remain in the upper layers of the SC (0-20% of SC thickness) and show predominated differences of ICL ordering from intact skin. In these depths, skin treated with plant-derived oils shows more disordered lateral and lamellar packing order of ICL than intact skin (p<0.05). In the intermediate layers of SC (30-50% of SC thickness), the oils do not influence the lateral packing order of SC ICL (p>0.1), except plant-derived oils at the depth 30% of SC thickness. In the deeper layers of the SC (60-100% of SC thickness), no difference between ICL lateral packing order of the oil-treated and intact skin can be observed, except that at the depths of 70-90% of the SC thickness, where slight changes with more disorder states are measured for plant-derived oil treated skin (p<0.1), which could be explained by the penetration of free fatty acid fractions in the deep-located SC areas. CONCLUSION Both oil types remain in the superficial layers of the SC (0-20% of the SC thickness). Skin treated with mineral- and plant-derived oils shows significantly higher disordered lateral and lamellar packing order of ICL in these layers of the SC compared to intact skin. Plant-derived oils significantly changed the ICL ordering in the depths of 30% and 70-90% of the SC thickness, which is likely due to the penetration of free fatty acids in the deeper layers of the SC.
Collapse
Affiliation(s)
- ChunSik Choe
- Charité - Universitätsmedizin Berlin, Department of Dermatology, Venerology and Allergology, Center of Experimental and Applied Cutaneous Physiology, Charitéplatz 1, 10117 Berlin, Germany; Kim Il Sung University, Ryongnam-Dong, Taesong District, Pyongyang, Democratic People's Republic of Korea
| | - Johannes Schleusener
- Charité - Universitätsmedizin Berlin, Department of Dermatology, Venerology and Allergology, Center of Experimental and Applied Cutaneous Physiology, Charitéplatz 1, 10117 Berlin, Germany
| | - Jürgen Lademann
- Charité - Universitätsmedizin Berlin, Department of Dermatology, Venerology and Allergology, Center of Experimental and Applied Cutaneous Physiology, Charitéplatz 1, 10117 Berlin, Germany
| | - Maxim E Darvin
- Charité - Universitätsmedizin Berlin, Department of Dermatology, Venerology and Allergology, Center of Experimental and Applied Cutaneous Physiology, Charitéplatz 1, 10117 Berlin, Germany.
| |
Collapse
|
30
|
Schroeter A, Stahlberg S, Školová B, Sonnenberger S, Eichner A, Huster D, Vávrová K, Hauß T, Dobner B, Neubert RHH, Vogel A. Phase separation in ceramide[NP] containing lipid model membranes: neutron diffraction and solid-state NMR. SOFT MATTER 2017; 13:2107-2119. [PMID: 28225091 DOI: 10.1039/c6sm02356h] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The stratum corneum is the outermost layer of the skin and protects the organism against external influences as well as water loss. It consists of corneocytes embedded in a mixture of ceramides, fatty acids, and cholesterol in a molar ratio of roughly 1 : 1 : 1. The unique structural and compositional arrangement of these stratum corneum lipids is responsible for the skin barrier properties. Many studies investigated the organization of these barrier lipids and, in particular, the exact conformation of ceramides. However, so far no consensus has been reached. In this study, we investigate a model system comprised of N-(non-hydroxy-tetracosanoyl)-phytosphingosine/cholesterol/tetracosanoic acid (CER[NP]-C24/CHOL/TA) at a 1 : 1 : 1 molar ratio using neutron diffraction and 2H solid-state NMR spectroscopy at temperatures from 25 °C to 80 °C. Deuterated variants of all three lipid components of the model system were used to enable their separate investigation in the NMR spectra and quantification of the amount of molecules in each phase. Neutron scattering experiments show the coexistence of two lipid phases at low temperatures with repeat spacings of 54.2 Å and 43.0 Å at a physiological skin temperature of 32 °C. They appear to be indistinguishable in the 2H NMR spectra as both phases are crystalline and ceramide molecules do not rotate around their long axis on a microsecond timescale. The evolution of these phases upon heating is followed and with increasing temperature fluid and even isotropically mobile molecules are observed. A model of the organization of the lamellar phases is proposed in which the thicker phase consists of CER[NP]-C24 in a hairpin conformation mixed with CHOL and TA, while the phase with a repeat spacing of 43.0 Å contains CER[NP]-C24 in a V-shape conformation.
Collapse
Affiliation(s)
- Annett Schroeter
- Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Sören Stahlberg
- Institute for Medical Physics and Biophysics, University of Leipzig, Härtelstraße 16-18, D-04107 Leipzig, Germany.
| | - Barbora Školová
- Institute for Medical Physics and Biophysics, University of Leipzig, Härtelstraße 16-18, D-04107 Leipzig, Germany. and Faculty of Pharmacy, Charles University, Akademika Heyrovského 1203, 50005 Hradec Králové, Czech Republic
| | - Stefan Sonnenberger
- Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Adina Eichner
- Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Daniel Huster
- Institute for Medical Physics and Biophysics, University of Leipzig, Härtelstraße 16-18, D-04107 Leipzig, Germany.
| | - Kateřina Vávrová
- Faculty of Pharmacy, Charles University, Akademika Heyrovského 1203, 50005 Hradec Králové, Czech Republic
| | - Thomas Hauß
- Institute of Soft Matter and Functional Materials, Helmholtz-Zentrum für Materialien und Energie, Berlin, Germany
| | - Bodo Dobner
- Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Reinhard H H Neubert
- Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany and Institute of Applied Dermatopharmacy at the Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Alexander Vogel
- Institute for Medical Physics and Biophysics, University of Leipzig, Härtelstraße 16-18, D-04107 Leipzig, Germany.
| |
Collapse
|