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Fisher HA, Evans MV, Bunge AL, Hubal EAC, Vallero DA. A compartment model to predict in vitro finite dose absorption of chemicals by human skin. CHEMOSPHERE 2024; 349:140689. [PMID: 37963497 PMCID: PMC10842870 DOI: 10.1016/j.chemosphere.2023.140689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 10/30/2023] [Accepted: 11/09/2023] [Indexed: 11/16/2023]
Abstract
Dermal uptake is an important and complex exposure route for a wide range of chemicals. Dermal exposure can occur due to occupational settings, pharmaceutical applications, environmental contamination, or consumer product use. The large range of both chemicals and scenarios of interest makes it difficult to perform generalizable experiments, creating a need for a generic model to simulate various scenarios. In this study, a model consisting of a series of four well-mixed compartments, representing the source solution (vehicle), stratum corneum, viable tissue, and receptor fluid, was developed for predicting dermal absorption. The model considers experimental conditions including small applied doses as well as evaporation of the vehicle and chemical. To evaluate the model assumptions, we compare model predictions for a set of 26 chemicals to finite dose in-vitro experiments from a single laboratory using steady-state permeability coefficient and equilibrium partition coefficient data derived from in-vitro experiments of infinite dose exposures to these same chemicals from a different laboratory. We find that the model accurately predicts, to within an order of magnitude, total absorption after 24 h for 19 of these chemicals. In combination with key information on experimental conditions, the model is generalizable and can advance efficient assessment of dermal exposure for chemical risk assessment.
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Affiliation(s)
- H A Fisher
- Oak Ridge Associated Universities, Assigned to U.S. Environmental Protection Agency, Office of Research and Development, Center for Computational Toxicology and Exposure, Research Triangle Park, NC, USA
| | - M V Evans
- U.S. Environmental Protection Agency, Office of Research and Development, Center for Computational Toxicology and Exposure, Research Triangle Park, NC, USA
| | - A L Bunge
- Chemical and Biological Engineering, Colorado School of Mines, Golden, CO, USA
| | - E A Cohen Hubal
- U.S. Environmental Protection Agency, Office of Research and Development, Center for Public Health and Environmental Assessment, Research Triangle Park, NC, USA
| | - D A Vallero
- U.S. Environmental Protection Agency, Office of Research and Development, Center for Computational Toxicology and Exposure, Research Triangle Park, NC, USA.
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2
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Wang Z, Geng S, Zhang J, Yang H, Shi S, Zhao L, Luo X, Cao Z. Methods for the characterisation of dermal uptake: Progress and perspectives for organophosphate esters. ENVIRONMENT INTERNATIONAL 2024; 183:108400. [PMID: 38142534 DOI: 10.1016/j.envint.2023.108400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 12/18/2023] [Accepted: 12/19/2023] [Indexed: 12/26/2023]
Abstract
Organophosphate esters (OPEs) are a group of pollutants that are widely detected in the environment at high concentrations. They can adversely affect human health through multiple routes of exposure, including dermal uptake. Although attention has been paid to achieving an accurate and complete quantification of the dermal uptake of OPEs, existing evaluation methods and parameters have obvious weaknesses. This study reviewed two main categories of methodologies, namely the relative absorption (RA) model and the permeability coefficient (PC) model, which are widely used to assess the dermal uptake of OPEs. Although the PC model is more accurate and is increasingly used, the most important parameter in this model, the permeability coefficient (Kp), has been poorly characterised for OPEs, resulting in considerable errors in the estimation of the dermal uptake of OPEs. Thus, the detailed in vitro methods for the determination of Kp are summarised and sorted. Furthermore, the commonly used skin membranes are identified and the factors affecting Kp and corresponding mechanisms are discussed. In addition, the experimental conditions, conclusions, and available data on Kp values of the OPEs are thoroughly summarised. Finally, the corresponding knowledge gaps are proposed, and a more accurate and sophisticated experimental system and unknown Kp values for OPEs are suggested.
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Affiliation(s)
- Zhexi Wang
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Normal University, Xinxiang 453007, China
| | - Shuxiang Geng
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Normal University, Xinxiang 453007, China
| | - Jiayi Zhang
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Normal University, Xinxiang 453007, China
| | - Hengkang Yang
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Normal University, Xinxiang 453007, China
| | - Shiyu Shi
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Normal University, Xinxiang 453007, China
| | - Leicheng Zhao
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Normal University, Xinxiang 453007, China
| | - Xiaojun Luo
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Resources Utilization and Protection, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.
| | - Zhiguo Cao
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Normal University, Xinxiang 453007, China.
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Zhang Q, Alinaghi A, Williams DB, Roberts MS. A thermodynamic and kinetic analysis of human epidermal penetration of phenolic compounds: II. Maximum flux and solute diffusion through stratum corneum lipids. Int J Pharm 2023; 631:122522. [PMID: 36563793 DOI: 10.1016/j.ijpharm.2022.122522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 11/17/2022] [Accepted: 12/16/2022] [Indexed: 12/24/2022]
Abstract
Warming the skin is a key means of promoting solute permeation through the skin. Changes in solute permeation associated with variations in skin temperature also assist in understanding the mechanism by which solutes permeate the skin. However, few studies have considered the relative impact of temperature on the main determinants of the maximum flux for a solute across the skin, the solubility of a solute and its diffusivity in the stratum corneum. In this study, we quantified for the first time the thermodynamics associated with the maximum skin fluxes for a series of phenolic compounds of similar size but with varying lipophilicity (defined by the logarithms of their octanol/water partition coefficient, logP). These studies were undertaken using aqueous donor solutions (along with testosterone as a reference solute) across human epidermal membranes in vertical Franz diffusion cells at 4 °C, 24 °C and 37 °C with intermittent receptor sampling and volume replacement over 24 h. Kinetic and thermodynamic analyses included the estimation of the stratum corneum (SC) apparent SC diffusivity from the SC maximum fluxes and SC solubilities and the associated activation energies, enthalpies and entropies for diffusion. The key findings were that the differences in the maximum flux of phenolic compounds varying in lipophilicity mainly arose from differences in SC solubility at the various temperatures and that, at the highest temperature, SC permeability and SC diffusion were affected by SC lipid fluidisation and that variations in SC - water partitioning enthalpies explain some of the previously low activation energies for permeation of the more lipophilic phenols. Higher enthalpies for diffusion were seen for solutes with addition hydrogen bonding capacity and the highest negative entropy was observed with the more compact solutes. Various relationships between the derived thermodynamic parameters were explored and interpreted in a proposed model for solute partitioning into and permeation through the SC intercellular lipid lamellae.
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Affiliation(s)
- Qian Zhang
- Clinical and Health Sciences, University of South Australia, Adelaide SA 5001, Australia; Current address: Acrux DDS Pty Ltd, 103-113 Stanley St, West Melbourne, VIC 3003, Australia
| | - Azadeh Alinaghi
- Clinical and Health Sciences, University of South Australia, Adelaide SA 5001, Australia; Basil Hetzel Institute for Translational Health Research, The Queen Elizabeth Hospital, Adelaide, SA, Australia
| | - Desmond B Williams
- Clinical and Health Sciences, University of South Australia, Adelaide SA 5001, Australia
| | - Michael S Roberts
- Clinical and Health Sciences, University of South Australia, Adelaide SA 5001, Australia; Basil Hetzel Institute for Translational Health Research, The Queen Elizabeth Hospital, Adelaide, SA, Australia; Therapeutics Research Centre, Frazer Institute, University of Queensland, Translational Research Institute, Brisbane, QLD, Australia.
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Thermodynamic and kinetic analysis of human epidermal penetration of phenolic compounds: I. Stratum corneum solubility and partitioning. Int J Pharm 2022; 630:122424. [PMID: 36427696 DOI: 10.1016/j.ijpharm.2022.122424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 11/15/2022] [Accepted: 11/17/2022] [Indexed: 11/26/2022]
Abstract
Warming of the skin is now an accepted means of promoting skin permeation. Accordingly, the usually quite onerous thermodynamic studies on solute transport through the skin have practical applications. Phenolic compounds permeate through the skin by partitioning into and diffusing through the stratum corneum (SC) intercellular lipids, with their size being the main determinant of their maximal solute flux through skin. This paper sought to characterise the enthalpic and entropic changes associated with the solubility and equilibrium partitioning into the human SC of a series of phenols similar in size but with differing log P from aqueous vehicles. The solubilities of 9 phenolic compounds, covering a range of polarities, were determined in water and SC following 72 h at 4, 24, 32 and 37 °C which allowed the estimation of the SC-water partition coefficients. Van't Hoff plots were then used to estimate the enthalpies and entropies for the SC solubility, water solubility and SC partitioning of phenols. In addition, partition coefficients of 3 of the 9 phenols from mineral oil into hydrated and dehydrated SC were measured at the same temperatures. Van't Hoff plots were then used to estimate the enthalpies and entropies for the SC solubility, water solubility and SC partitioning of phenols from the oil. The SC solubility for the polar phenols increased more with temperature than the non-polar phenols, with the SC-water partition coefficients increasing with temperature for the polar phenols but decreasing with temperature for the non-polar phenols. Thermodynamic analyses suggest that, while enthalpy and entropy effects are involved in the SC partitioning of the non-polar solutes, the SC partitioning of the polar phenols were almost entirely entropy driven. The resultant thermodynamic parameters are consistent with the polar phenols being mainly associated with the SC polar head groups whereas the nonpolar phenols were more likely to be located in the interior interface SC lipid region adjacent to the polar head groups. Further, hydrating the SC led to an increase in the enthalpy of partitioning for both the polar and non-polar phenols studied. The estimated entropy of the partitioning for solutes from dehydrated SC suggests this is not only a hydrophobic effect in water but that the partitioning arises from the nature of phenolic compound - SC intercellular lipid interactions and SC intercellular lipid entropy. This partitioning process is dominated more by the extent of interaction between the SC and solute than the hydrophobic effect in water and is likely to be even greater above the SC lipid phase transition at around 36 °C for hydrated epidermal membranes.
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Sarheed O, Shouqair D, Ramesh KVRNS, Khaleel T, Amin M, Boateng J, Drechsler M. Formation of stable nanoemulsions by ultrasound-assisted two-step emulsification process for topical drug delivery: Effect of oil phase composition and surfactant concentration and loratadine as ripening inhibitor. Int J Pharm 2019; 576:118952. [PMID: 31843549 DOI: 10.1016/j.ijpharm.2019.118952] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 11/14/2019] [Accepted: 12/11/2019] [Indexed: 01/02/2023]
Abstract
Nanoemulsions are very interesting systems as they offer capacity to encapsulate both hydrophilic and lipophilic molecules in a single particle, as well as the controlled release of chemical moieties initially entrapped in the internal droplets. In this study, we propose a new two-step modified ultrasound-assisted phase inversion approaches-phase inversion temperature (PIT) and self-emulsification, to prepare stable o/w nanoemulsions from a fully water-dilutable microemulsion template for the transdermal delivery of loratadine (a hydrophobe and as Ostwald ripening inhibitor). Firstly, the primary water-in-oil microemulsion concentrate (w/o) was formed using loratadine in the oil phase (oleic acid or coconut oil) and Tween 80 in the aqueous phase and by adjusting the PIT around 85 °C followed by stepwise dilution with water at 25 °C to initiate the formation the nanoemulsions (o/w). To assure the long-term stability, a brief application of low frequency ultrasound was employed. Combining the two low energy methods resulted in nanoemulsions prepared by mixing constant surfactant/oil ratios above the PIT with varying water volume fraction (self-emulsification) during the PIT by stepwise dilution. The kinetic stability was evaluated by measuring the droplet size with time by dynamic light scattering (DLS). The droplet size ranged 15-43 nm and did not exceed 100 nm over the period of 6 months indicating the system had high kinetic stability. Cryo-TEM showed that the nanoemulsions droplets were monodispersed and approaching micellar structure and scale. All nanoemulsions had loratadine crystals formed within 20 days after preparation, which tended to sediment during storage. Nanoemulsions improved the in vitro permeation of loratadine through porcine skin up to 20 times compared to the saturated solution.
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Affiliation(s)
- Omar Sarheed
- RAK College of Pharmaceutical Sciences, RAK Medical and Health Sciences University, Ras AlKhaimah, United Arab Emirates.
| | - Douha Shouqair
- RAK College of Pharmaceutical Sciences, RAK Medical and Health Sciences University, Ras AlKhaimah, United Arab Emirates
| | - K V R N S Ramesh
- RAK College of Pharmaceutical Sciences, RAK Medical and Health Sciences University, Ras AlKhaimah, United Arab Emirates
| | - Taha Khaleel
- RAK College of Pharmaceutical Sciences, RAK Medical and Health Sciences University, Ras AlKhaimah, United Arab Emirates
| | - Muhammad Amin
- School of Science, Faculty of Engineering and Science, University of Greenwich, UK
| | - Joshua Boateng
- School of Science, Faculty of Engineering and Science, University of Greenwich, UK
| | - Markus Drechsler
- Bavarian Polymer Institute, KeyLab "Electron and Optical Microscopy", University of Bayreuth, Germany
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Mechanistic Evaluation of Enhanced Curcumin Delivery through Human Skin In Vitro from Optimised Nanoemulsion Formulations Fabricated with Different Penetration Enhancers. Pharmaceutics 2019; 11:pharmaceutics11120639. [PMID: 31805660 PMCID: PMC6956259 DOI: 10.3390/pharmaceutics11120639] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 11/24/2019] [Accepted: 11/25/2019] [Indexed: 01/01/2023] Open
Abstract
Curcumin is a natural product with chemopreventive and other properties that are potentially useful in treating skin diseases, including psoriasis and melanoma. However, because of the excellent barrier function of the stratum corneum and the relatively high lipophilicity of curcumin (log P 3.6), skin delivery of curcumin is challenging. We used the principles of a Quality by Design (QbD) approach to develop nanoemulsion formulations containing biocompatible components, including Labrasol and Lecithin as surfactants and Transcutol and ethanol as cosurfactants, to enhance the skin delivery of curcumin. The nanoemulsions were characterised by cryo-SEM, Zeta potential, droplet size, pH, electrical conductivity (EC) and viscosity (η). Physicochemical long-term stability (6 months) was also investigated. The mean droplet sizes as determined by dynamic light scattering (DLS) were in the lower submicron range (20–50 nm) and the average Zeta potential values were low (range: −0.12 to −2.98 mV). Newtonian flow was suggested for the nanoemulsions investigated, with dynamic viscosity of the nanoemulsion formulations ranging from 5.8 to 31 cP. The droplet size of curcumin loaded formulations remained largely constant over a 6-month storage period. The inclusion of terpenes to further enhance skin permeation was also examined. All nanoemulsions significantly enhanced the permeation of curcumin through heat-separated human epidermal membranes, with the greatest effect being a 28-fold increase in maximum flux (Jmax) achieved with a limonene-based nanoemulsion, compared to a 60% ethanol in water control vehicle. The increases in curcumin flux were associated with increased skin diffusivity. In summary, we demonstrated the effectiveness of nanoemulsions for the skin delivery of the lipophilic active compound curcumin, and elucidated the mechanism of permeation enhancement. These formulations show promise as delivery vehicles for curcumin to target psoriasis and skin cancer, and more broadly for other skin delivery applications.
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Abd E, Benson H, Mohammed Y, Roberts M, Grice J. Permeation Mechanism of Caffeine and Naproxen through in vitro Human Epidermis: Effect of Vehicles and Penetration Enhancers. Skin Pharmacol Physiol 2019; 32:132-141. [DOI: 10.1159/000497225] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 01/18/2019] [Indexed: 11/19/2022]
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9
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Bonnel D, Legouffe R, Eriksson AH, Mortensen RW, Pamelard F, Stauber J, Nielsen KT. MALDI imaging facilitates new topical drug development process by determining quantitative skin distribution profiles. Anal Bioanal Chem 2018; 410:2815-2828. [PMID: 29546543 DOI: 10.1007/s00216-018-0964-3] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 02/07/2018] [Accepted: 02/14/2018] [Indexed: 01/10/2023]
Abstract
Generation of skin distribution profiles and reliable determination of drug molecule concentration in the target region are crucial during the development process of topical products for treatment of skin diseases like psoriasis and atopic dermatitis. Imaging techniques like mass spectrometric imaging (MSI) offer sufficient spatial resolution to generate meaningful distribution profiles of a drug molecule across a skin section. In this study, we use matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) to generate quantitative skin distribution profiles based on tissue extinction coefficient (TEC) determinations of four different molecules in cross sections of human skin explants after topical administration. The four drug molecules: roflumilast, tofacitinib, ruxolitinib, and LEO 29102 have different physicochemical properties. In addition, tofacitinib was administrated in two different formulations. The study reveals that with MALDI-MSI, we were able to observe differences in penetration profiles for both the four drug molecules and the two formulations and thereby demonstrate its applicability as a screening tool when developing a topical drug product. Furthermore, the study reveals that the sensitivity of the MALDI-MSI techniques appears to be inversely correlated to the drug molecules' ability to bind to the surrounding tissues, which can be estimated by their Log D values. Graphical abstract.
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Affiliation(s)
- David Bonnel
- ImaBiotech SAS, Parc Eurasanté, 885 Avenue Eugène Avinée, 59120, Loos, France
| | - Raphaël Legouffe
- ImaBiotech SAS, Parc Eurasanté, 885 Avenue Eugène Avinée, 59120, Loos, France
| | | | | | - Fabien Pamelard
- ImaBiotech SAS, Parc Eurasanté, 885 Avenue Eugène Avinée, 59120, Loos, France
| | - Jonathan Stauber
- ImaBiotech SAS, Parc Eurasanté, 885 Avenue Eugène Avinée, 59120, Loos, France.,ImaBiotech Corp, 44 Manning Road Unit 3, Billerica, MA, 01821, USA
| | - Kim T Nielsen
- LEO Pharma A/S, Industriparken 55, 2750, Ballerup, Denmark.
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Ashrafi P, Sun Y, Davey N, Adams RG, Wilkinson SC, Moss GP. Model fitting for small skin permeability data sets: hyperparameter optimisation in Gaussian Process Regression. J Pharm Pharmacol 2018; 70:361-373. [PMID: 29341138 DOI: 10.1111/jphp.12863] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 11/22/2017] [Indexed: 11/30/2022]
Abstract
OBJECTIVES The aim of this study was to investigate how to improve predictions from Gaussian Process models by optimising the model hyperparameters. METHODS Optimisation methods, including Grid Search, Conjugate Gradient, Random Search, Evolutionary Algorithm and Hyper-prior, were evaluated and applied to previously published data. Data sets were also altered in a structured manner to reduce their size, which retained the range, or 'chemical space' of the key descriptors to assess the effect of the data range on model quality. KEY FINDINGS The Hyper-prior Smoothbox kernel results in the best models for the majority of data sets, and they exhibited significantly better performance than benchmark quantitative structure-permeability relationship (QSPR) models. When the data sets were systematically reduced in size, the different optimisation methods generally retained their statistical quality, whereas benchmark QSPR models performed poorly. CONCLUSIONS The design of the data set, and possibly also the approach to validation of the model, is critical in the development of improved models. The size of the data set, if carefully controlled, was not generally a significant factor for these models and that models of excellent statistical quality could be produced from substantially smaller data sets.
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Affiliation(s)
- Parivash Ashrafi
- School of Computer Science, University of Hertfordshire, Hatfield, UK
| | - Yi Sun
- School of Computer Science, University of Hertfordshire, Hatfield, UK
| | - Neil Davey
- School of Computer Science, University of Hertfordshire, Hatfield, UK
| | - Roderick G Adams
- School of Computer Science, University of Hertfordshire, Hatfield, UK
| | - Simon C Wilkinson
- Medical Toxicology Centre, Wolfson Unit, Medical School, University of Newcastle-upon-Tyne, Newcastle upon Tyne, UK
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Abd E, Benson HAE, Roberts MS, Grice JE. Minoxidil Skin Delivery from Nanoemulsion Formulations Containing Eucalyptol or Oleic Acid: Enhanced Diffusivity and Follicular Targeting. Pharmaceutics 2018; 10:E19. [PMID: 29370122 PMCID: PMC5874832 DOI: 10.3390/pharmaceutics10010019] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Revised: 01/14/2018] [Accepted: 01/14/2018] [Indexed: 12/26/2022] Open
Abstract
In this work, we examined enhanced skin delivery of minoxidil applied in nanoemulsions incorporating skin penetration enhancers. Aliquots of fully characterized oil-in-water nanoemulsions (1 mL), containing minoxidil (2%) and the skin penetration enhancer oleic acid or eucalyptol as oil phases, were applied to full-thickness excised human skin in Franz diffusion cells, while aqueous solutions (1 mL) containing minoxidil were used as controls. Minoxidil in the stratum corneum (SC), hair follicles, deeper skin layers, and flux through the skin over 24 h was determined, as well as minoxidil solubility in the formulations and in the SC. The nanoemulsions significantly enhanced the permeation of minoxidil through skin compared with control solutions. The eucalyptol formulations (NE) promoted minoxidil retention in the SC and deeper skin layers more than did the oleic acid formulations, while the oleic acid formulations (NO) gave the greatest hair follicle penetration. Minoxidil maximum flux enhancement was associated with increases in both minoxidil SC solubility and skin diffusivity in both nanoemulsion systems. The mechanism of enhancement appeared to be driven largely by increased diffusivity, rather than increased partitioning into the stratum corneum, supporting the concept of enhanced fluidity and disruption of stratum corneum lipids.
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Affiliation(s)
- Eman Abd
- Therapeutics Research Centre, School of Medicine, Translational Research Institute, University of Queensland, Brisbane 4102, Australia.
| | - Heather A E Benson
- Curtin Health Innovation Research Institute, School of Pharmacy, Curtin University, Perth 6845, Australia.
| | - Michael S Roberts
- Therapeutics Research Centre, School of Medicine, Translational Research Institute, University of Queensland, Brisbane 4102, Australia.
- School of Pharmacy and Medical Sciences, University of South Australia, Adelaide 5000, Australia.
| | - Jeffrey E Grice
- Therapeutics Research Centre, School of Medicine, Translational Research Institute, University of Queensland, Brisbane 4102, Australia.
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12
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Intarakumhaeng R, Wanasathop A, Li SK. Effects of solvents on skin absorption of nonvolatile lipophilic and polar solutes under finite dose conditions. Int J Pharm 2018; 536:405-413. [DOI: 10.1016/j.ijpharm.2017.11.042] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 09/07/2017] [Accepted: 11/19/2017] [Indexed: 12/01/2022]
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13
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Zhang Q, Song Y, Page SW, Garg S. Evaluation of Transdermal Drug Permeation as Modulated by Lipoderm and Pluronic Lecithin Organogel. J Pharm Sci 2017; 107:587-594. [PMID: 28935590 DOI: 10.1016/j.xphs.2017.09.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 08/31/2017] [Accepted: 09/11/2017] [Indexed: 11/26/2022]
Abstract
The transdermal delivery of 2 fluorescent probes with similar molecular weight but different lipophilicity, into and through the skin from 2 commercially available transdermal bases, pluronic lecithin organogel, and Lipoderm® has been evaluated. First, in vitro penetration of fluorescein sodium and fluorescein (free acid) through porcine skin was evaluated. Retention and depth distribution profiles in skin were obtained by tape stripping and then followed by optical sectioning using multiphoton microscopy. The results showed that Lipoderm® led to an enhanced penetration of the hydrophilic compound, fluorescein sodium. For the lipophilic compound fluorescein (free acid), Lipoderm® performed similar to pluronic lecithin organogel base, where minimal drug was detected in either receptor phase. The skin retention and depth distribution results also showed that the hydrophilic fluorescein sodium had high skin retention with Lipoderm®, whereas fluorescein (free acid) had very low penetration and retention with increasing skin depth. Moreover, optical sectioning by multiphoton microscopy revealed an uneven distribution of probes across the skin in the x-y plane for both transdermal bases. This work showed that a hydrophilic compound has significantly increased skin penetration and retention when formulated with Lipoderm®, and the skin retention of the probe was the main determinant of its skin flux.
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Affiliation(s)
- Qian Zhang
- Centre for Pharmaceutical Innovation and Development, School of Pharmacy and Medical Science, University of South Australia, Adelaide 5000, South Australia, Australia
| | - Yunmei Song
- Centre for Pharmaceutical Innovation and Development, School of Pharmacy and Medical Science, University of South Australia, Adelaide 5000, South Australia, Australia
| | - Stephen W Page
- Luoda Pharma, Caringbah 2229, New South Wales, Australia
| | - Sanjay Garg
- Centre for Pharmaceutical Innovation and Development, School of Pharmacy and Medical Science, University of South Australia, Adelaide 5000, South Australia, Australia.
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14
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Combination of MALDI-MSI and cassette dosing for evaluation of drug distribution in human skin explant. Anal Bioanal Chem 2017; 409:4993-5005. [DOI: 10.1007/s00216-017-0443-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 05/24/2017] [Accepted: 05/31/2017] [Indexed: 12/30/2022]
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15
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Abd E, Yousef SA, Pastore MN, Telaprolu K, Mohammed YH, Namjoshi S, Grice JE, Roberts MS. Skin models for the testing of transdermal drugs. Clin Pharmacol 2016; 8:163-176. [PMID: 27799831 PMCID: PMC5076797 DOI: 10.2147/cpaa.s64788] [Citation(s) in RCA: 143] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The assessment of percutaneous permeation of molecules is a key step in the evaluation of dermal or transdermal delivery systems. If the drugs are intended for delivery to humans, the most appropriate setting in which to do the assessment is the in vivo human. However, this may not be possible for ethical, practical, or economic reasons, particularly in the early phases of development. It is thus necessary to find alternative methods using accessible and reproducible surrogates for in vivo human skin. A range of models has been developed, including ex vivo human skin, usually obtained from cadavers or plastic surgery patients, ex vivo animal skin, and artificial or reconstructed skin models. Increasingly, largely driven by regulatory authorities and industry, there is a focus on developing standardized techniques and protocols. With this comes the need to demonstrate that the surrogate models produce results that correlate with those from in vivo human studies and that they can be used to show bioequivalence of different topical products. This review discusses the alternative skin models that have been developed as surrogates for normal and diseased skin and examines the concepts of using model systems for in vitro–in vivo correlation and the demonstration of bioequivalence.
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Affiliation(s)
- Eman Abd
- Translational Research Institute, School of Medicine, University of Queensland, Brisbane
| | - Shereen A Yousef
- Translational Research Institute, School of Medicine, University of Queensland, Brisbane
| | - Michael N Pastore
- School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, Australia
| | - Krishna Telaprolu
- Translational Research Institute, School of Medicine, University of Queensland, Brisbane
| | - Yousuf H Mohammed
- Translational Research Institute, School of Medicine, University of Queensland, Brisbane
| | - Sarika Namjoshi
- Translational Research Institute, School of Medicine, University of Queensland, Brisbane
| | - Jeffrey E Grice
- Translational Research Institute, School of Medicine, University of Queensland, Brisbane
| | - Michael S Roberts
- Translational Research Institute, School of Medicine, University of Queensland, Brisbane; School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, Australia
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16
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Yousef S, Mohammed Y, Namjoshi S, Grice J, Sakran W, Roberts M. Mechanistic Evaluation of Hydration Effects on the Human Epidermal Permeation of Salicylate Esters. AAPS JOURNAL 2016; 19:180-190. [PMID: 27634383 DOI: 10.1208/s12248-016-9984-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 08/30/2016] [Indexed: 11/30/2022]
Abstract
We sought to understand when and how hydration enhances the percutaneous absorption of salicylate esters. Human epidermal membrane fluxes and stratum corneum solubilities of neat and diluted solutions of three esters were determined under hydrated and dehydrated conditions. Hydration doubled the human epidermal flux seen for methyl and ethyl salicylate under dehydrated conditions and increased the flux of neat glycol salicylate 10-fold. Mechanistic analyses showed that this hydration-induced enhancement arises mainly from an increase in the stratum corneum diffusivity of the three esters. Further, we showed that unlike methyl and ethyl salicylate, glycol salicylate is hygroscopic and the ∼10-fold hydration-induced flux enhancement seen with neat glycol salicylate may be due to its ability to hydrate the stratum corneum to a greater extent. The hydration-induced enhancements in in vitro epidermal flux seen here for glycol and ethyl salicylate were similar to those reported for their percutaneous absorption rates in a comparable in vivo study, whilst somewhat higher enhancement was seen for methyl salicylate in vivo. This may be explained by a physiologically induced self enhancement of neat methyl salicylate absorption in vivo which is not applicable in vitro.
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Affiliation(s)
- Shereen Yousef
- Therapeutics Research Centre, School of Medicine, University of Queensland, Translational Research Institute, Brisbane, Australia.,School of Pharmacy, Helwan University, Helwan, Egypt
| | - Yousuf Mohammed
- Therapeutics Research Centre, School of Medicine, University of Queensland, Translational Research Institute, Brisbane, Australia
| | - Sarika Namjoshi
- Therapeutics Research Centre, School of Medicine, University of Queensland, Translational Research Institute, Brisbane, Australia
| | - Jeffrey Grice
- Therapeutics Research Centre, School of Medicine, University of Queensland, Translational Research Institute, Brisbane, Australia
| | - Wedad Sakran
- School of Pharmacy, Helwan University, Helwan, Egypt
| | - Michael Roberts
- Therapeutics Research Centre, School of Medicine, University of Queensland, Translational Research Institute, Brisbane, Australia. .,School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, Australia. .,Therapeutics Research Centre, The University of Queensland School of Medicine-Translational Research Institute, 37 Kent St, Woolloongabba, Brisbane, QLD, 4102, Australia.
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17
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Zhang A, Jung EC, Zhu H, Zou Y, Hui X, Maibach H. Vehicle effects on human stratum corneum absorption and skin penetration. Toxicol Ind Health 2016; 33:416-425. [PMID: 27436841 DOI: 10.1177/0748233716656119] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This study evaluated the effects of three vehicles-ethanol (EtOH), isopropyl alcohol (IPA), and isopropyl myristate (IPM)-on stratum corneum (SC) absorption and diffusion of the [14C]-model compounds benzoic acid and butenafine hydrochloride to better understand the transport pathways of chemicals passing through and resident in SC. Following application of topical formulations to human dermatomed skin for 30 min, penetration flux was observed for 24 h post dosing, using an in vitro flow-through skin diffusion system. Skin absorption and penetration was compared to the chemical-SC (intact, delipidized, or SC lipid film) binding levels. A significant vehicle effect was observed for chemical skin penetration and SC absorption. IPA resulted in the greatest levels of intact SC/SC lipid absorption, skin penetration, and total skin absorption/penetration of benzoic acid, followed by IPM and EtOH, respectively. For intact SC absorption and total skin absorption/penetration of butenafine, the vehicle that demonstrated the highest level of sorption/penetration was EtOH, followed by IPA and IPM, respectively. The percent doses of butenafine that were absorbed in SC lipid film and penetrated through skin in 24 h were greatest for IPA, followed by EtOH and IPM, respectively. The vehicle effect was consistent between intact SC absorption and total chemical skin absorption and penetration, as well as SC lipid absorption and chemical penetration through skin, suggesting intercellular transport as a main pathway of skin penetration for model chemicals. These results suggest the potential to predict vehicle effects on skin permeability with simple SC absorption assays. As decontamination was applied 30 min after chemical exposure, significant vehicle effects on chemical SC partitioning and percutaneous penetration also suggest that skin decontamination efficiency is vehicle dependent, and an effective decontamination method should act on chemical solutes in the lipid domain.
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Affiliation(s)
- Alissa Zhang
- 1 Department of Chemical and Physical Biology, Harvard University, Cambridge, MA, USA
| | - Eui-Chang Jung
- 2 Department of Dermatology, University of California San Francisco, San Francisco, CA, USA
| | - Hanjiang Zhu
- 2 Department of Dermatology, University of California San Francisco, San Francisco, CA, USA
| | - Ying Zou
- 3 Skin & Cosmetic Research Department, Shanghai Skin Disease Hospital, Shanghai, China
| | - Xiaoying Hui
- 2 Department of Dermatology, University of California San Francisco, San Francisco, CA, USA
| | - Howard Maibach
- 2 Department of Dermatology, University of California San Francisco, San Francisco, CA, USA
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Taevernier L, Veryser L, Roche N, Peremans K, Burvenich C, Delesalle C, De Spiegeleer B. Human skin permeation of emerging mycotoxins (beauvericin and enniatins). JOURNAL OF EXPOSURE SCIENCE & ENVIRONMENTAL EPIDEMIOLOGY 2016; 26:277-287. [PMID: 25757886 DOI: 10.1038/jes.2015.10] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 10/23/2014] [Accepted: 01/05/2015] [Indexed: 06/04/2023]
Abstract
Currently, dermal exposure data of cyclic depsipeptide mycotoxins are completely absent. There is a lack of understanding about the local skin and systemic kinetics and effects, despite their widespread skin contact and intrinsic hazard. Therefore, we provide a quantitative characterisation of their dermal kinetics. The emerging mycotoxins enniatins (ENNs) and beauvericin (BEA) were used as model compounds and their transdermal kinetics were quantitatively evaluated, using intact and damaged human skin in an in vitro Franz diffusion cell set-up and ultra high-performance liquid chromatography (UHPLC)-MS analytics. We demonstrated that all investigated mycotoxins are able to penetrate through the skin. ENN B showed the highest permeation (kp,v=9.44 × 10(-6) cm/h), whereas BEA showed the lowest (kp,v=2.35 × 10(-6) cm/h) and the other ENNs ranging in between. Combining these values with experimentally determined solubility data, Jmax values ranging from 0.02 to 0.35 μg/(cm(2) h) for intact skin and from 0.07 to 1.11 μg/(cm(2) h) for damaged skin were obtained. These were used to determine the daily dermal exposure (DDE) in a worst-case scenario. On the other hand, DDE's for a typical occupational scenario were calculated based on real-life mycotoxin concentrations for the industrial exposure of food-related workers. In the latter case, for contact with intact human skin, DDE's up to 0.0870 ng/(kg BW × day) for ENN A were calculated, whereas for impaired skin barrier this can even rise up to 0.3209 ng/(kg BW × day) for ENN B1. This knowledge is needed for the risk assessment after skin exposure of contaminated food, feed, indoor surfaces and airborne particles with mycotoxins.
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Affiliation(s)
- Lien Taevernier
- Drug Quality and Registration (DruQuaR) Group, Department of Pharmaceutical Analysis, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, Ghent, Belgium
| | - Lieselotte Veryser
- Drug Quality and Registration (DruQuaR) Group, Department of Pharmaceutical Analysis, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, Ghent, Belgium
| | - Nathalie Roche
- Department of Plastic and Reconstructive Surgery, University Hospital Ghent, De Pintelaan 185, Ghent, Belgium
| | - Kathelijne Peremans
- Department of Medical Imaging and Small Animal Orthopaedics, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, Merelbeke, Belgium
| | - Christian Burvenich
- Department of Comparative Physiology and Biometrics, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, Merelbeke, Belgium
| | - Catherine Delesalle
- Department of Comparative Physiology and Biometrics, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, Merelbeke, Belgium
| | - Bart De Spiegeleer
- Drug Quality and Registration (DruQuaR) Group, Department of Pharmaceutical Analysis, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, Ghent, Belgium
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19
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Abd E, Namjoshi S, Mohammed YH, Roberts MS, Grice JE. Synergistic Skin Penetration Enhancer and Nanoemulsion Formulations Promote the Human Epidermal Permeation of Caffeine and Naproxen. J Pharm Sci 2016; 105:212-20. [PMID: 26554868 DOI: 10.1002/jps.24699] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 09/18/2015] [Accepted: 09/30/2015] [Indexed: 11/07/2022]
Abstract
We examined the extent of skin permeation enhancement of the hydrophilic drug caffeine and lipophilic drug naproxen applied in nanoemulsions incorporating skin penetration enhancers. Infinite doses of fully characterized oil-in-water nanoemulsions containing the skin penetration enhancers oleic acid or eucalyptol as oil phases and caffeine (3%) or naproxen (2%) were applied to human epidermal membranes in Franz diffusion cells, along with aqueous control solutions. Caffeine and naproxen fluxes were determined over 8 h. Solute solubility in the formulations and in the stratum corneum (SC), as well as the uptake of product components into the SC were measured. The nanoemulsions significantly enhanced the skin penetration of caffeine and naproxen, compared to aqueous control solutions. Caffeine maximum flux enhancement was associated with a synergistic increase in both caffeine SC solubility and skin diffusivity, whereas a formulation-increased solubility in the SC was the dominant determinant for increased naproxen fluxes. Enhancements in SC solubility were related to the uptake of the formulation excipients containing the active compounds into the SC. Enhanced skin penetration in these systems is largely driven by uptake of formulation excipients containing the active compounds into the SC with impacts on SC solubility and diffusivity.
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20
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Effects of solvent on percutaneous absorption of nonvolatile lipophilic solute. Int J Pharm 2014; 476:266-76. [PMID: 25261711 DOI: 10.1016/j.ijpharm.2014.09.034] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Revised: 09/14/2014] [Accepted: 09/23/2014] [Indexed: 11/21/2022]
Abstract
Understanding the effects of solvents upon percutaneous absorption can improve drug delivery across skin and allow better risk assessment of toxic compound exposure. The objective of the present study was to examine the effects of solvents upon the deposition of a moderately lipophilic solute at a low dose in the stratum corneum (SC) that could influence skin absorption of the solute after topical application. Skin permeation experiments were performed using Franz diffusion cells and human epidermal membrane (HEM). Radiolabeled corticosterone ((3)H-CS) was the model permeant. The solvents used had different evaporation and skin penetration properties that were expected to impact skin deposition of CS and its absorption across skin. The results show no correlation between the rate of absorption of the permeant and the rate of solvent evaporation/penetration with ethanol, hexane, isopropanol, and butanol as the solvent; all of these solvents have fast evaporation rates (complete evaporation in <30 min after application). This suggests no differences in solvent-induced deposition of CS in the SC for the fast-evaporating solvents. The results of these fast-evaporating solvents were different from those of water, propylene glycol, and polyethylene glycol 400, that a relationship between permeant absorption and the rate of solvent evaporation was observed.
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Sjövall P, Greve TM, Clausen SK, Moller K, Eirefelt S, Johansson B, Nielsen KT. Imaging of distribution of topically applied drug molecules in mouse skin by combination of time-of-flight secondary ion mass spectrometry and scanning electron microscopy. Anal Chem 2014; 86:3443-52. [PMID: 24568123 DOI: 10.1021/ac403924w] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In the development of topical drugs intended for local effects in the skin, one of the major challenges is to achieve drug penetration through the external barrier of the skin, stratum corneum, and secure exposure to the viable skin layers. Mass spectrometric imaging offers an opportunity to study drug penetration in a variety of skin models by mapping the spatial distribution in different skin layers after topical application of the drug. In this study, we used time-of-flight secondary ion mass spectrometry (TOF-SIMS) and scanning electron microscopy (SEM) to image the distribution of three drug molecules in skin tissue cross sections of inflamed mouse ear. The three compounds, roflumilast, tofacitinib, and ruxolitinib, were topically administered to the mouse ears, which were subsequently cryosectioned and thawed for the analyses. The results reveal that the combination of TOF-SIMS and SEM was beneficial for interpretation of drug distribution. SEM identified the different skin layers, while spatial distributions of all three compounds could be visualized by TOF-SIMS, showing that the drug was primarily distributed into, or on the top of, the stratum corneum. Imaging of endogenous skin components like cholesterol, phospholipids, ceramides, and free fatty acids showed distributions in good agreement with the literature. One limitation of the TOF-SIMS method is sensitivity, typically allowing for analysis in the millimolar range rather than the pharmacologically relevant micromolar range. However, the data presented demonstrate the potential of the technique for studying the penetration of drugs with different physicochemical properties in skin.
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Affiliation(s)
- Peter Sjövall
- SP Technical Research Institute of Sweden , Post Office Box 857, SE-50115 Borås, Sweden
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Roberts MS. Solute-vehicle-skin interactions in percutaneous absorption: the principles and the people. Skin Pharmacol Physiol 2013; 26:356-70. [PMID: 23921122 DOI: 10.1159/000353647] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
An appreciation of solute-vehicle-skin interactions underpins our current understanding of the processes of percutaneous absorption as well as in the prediction of the extent of absorption. This understanding has been reached through principles developed and validated over the last century through the work of a number of authors, including Dale Wurster, Takeru Higuchi, Irvin Blank, Robert Scheuplein, Gordon Flynn, Boyd Poulsen and Tom Franz, as well as by many scientists from my and younger generations. Their work has led to an appreciation of the rate-limiting steps in percutaneous penetration, the role played by the physicochemical properties of the solute, vehicle and skin and the variability that may arise from using various experimental/mathematical/pharmacokinetic models to quantify absorption as well as enabling the prediction of local and systemic efficacy and toxicity. In addition, unexpected behaviour may result from non-ideality in solute-vehicle-skin effects, including dehydration, chemical enhancement, supersaturation, metabolism, sequestration and vascular effects, including those of nanosystems on the local vasculature. In general, in vitro skin penetration profiles are predictive of in vivo profiles but a number of exceptions also exist.
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Affiliation(s)
- M S Roberts
- Therapeutics Research Centre, School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, S.A., Australia.
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23
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Wiechers JW, Watkinson AC, Cross SE, Roberts MS. Predicting skin penetration of actives from complex cosmetic formulations: an evaluation of inter formulation and inter active effects during formulation optimization for transdermal delivery. Int J Cosmet Sci 2012; 34:525-35. [DOI: 10.1111/ics.12001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Accepted: 08/26/2012] [Indexed: 11/29/2022]
Affiliation(s)
- J. W. Wiechers
- Therapeutics Research Centre; School of Medicine; Princess Alexandra Hospital; University of Queensland; Woolloongabba; Qld; 4102; Australia
| | - A. C. Watkinson
- Storith Consulting Limited; 138 High Street; Hythe; Kent; CT21 5JU; U.K
| | - S. E. Cross
- Therapeutics Research Centre; School of Medicine; Princess Alexandra Hospital; University of Queensland; Woolloongabba; Qld; 4102; Australia
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