Contamination of soil and water (ground and surface water) and the transfer of hazardous chemicals is a major concern. When the large surface area of skin is exposed to contaminated soil and water (work, play, swim, daily bath), skin absorption may be significant. Brown et al. (1) suggested that skin absorption of contaminants in water has been underestimated and that ingestion may not constitute the sole, or even the primary route of exposure. Soil has become an environmental depository for potentially hazardous chemicals. Exposure through work in pesticide-sprayed areas on chemical dump sites seems obvious. However, there may be hidden dangers in weekend gardening or in the child’s play area where the soil has become laden with lead or other hazardous chemicals.
{"title":"Skin contamination and absorption of chemicals from water and soil","authors":"R. Wester, H. Maibach","doi":"10.1081/CUS-120001863","DOIUrl":"https://doi.org/10.1081/CUS-120001863","url":null,"abstract":"Contamination of soil and water (ground and surface water) and the transfer of hazardous chemicals is a major concern. When the large surface area of skin is exposed to contaminated soil and water (work, play, swim, daily bath), skin absorption may be significant. Brown et al. (1) suggested that skin absorption of contaminants in water has been underestimated and that ingestion may not constitute the sole, or even the primary route of exposure. Soil has become an environmental depository for potentially hazardous chemicals. Exposure through work in pesticide-sprayed areas on chemical dump sites seems obvious. However, there may be hidden dangers in weekend gardening or in the child’s play area where the soil has become laden with lead or other hazardous chemicals.","PeriodicalId":17547,"journal":{"name":"Journal of Toxicology-cutaneous and Ocular Toxicology","volume":"115 4","pages":"319 - 333"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91477838","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fuel system maintenance usually requires direct, prolonged exposure to fuel. Thus, both military and commercial aircraft workers are at risk of dermal exposure and toxicity from JP-8 jet fuel. At present, there are no standards for U.S. Air Force personnel regarding dermal exposure to jet fuel. Hence, there are needs for data and approaches to understand the human hazard from dermal exposure to JP-8. In this study, we investigated the alteration in porcine skin at ultrastructural level, after a 24-h exposure to JP-8, with the help of transmission electron microscopy (TEM). Many ultrastructural modifications were noticed in the photomicrographs. Large-scale expansion in intercellular lipid domains of stratum corneum and disruption in its structural integrity; alteration in configuration of basal cells; rupture of hemidesmosomes and desmosomes; and diminished dendritic processes in Langerhans cells were observed. It is concluded that JP-8 exposure can cause alteration in skin anatomy, which may lead to dermal toxicity. Further studies are required to determine comparative damages incurred by individual components of JP-8.
{"title":"EFFECT OF JP-8 JET FUEL EXPOSURE ON THE ULTRASTRUCTURE OF SKIN","authors":"Somnath Singh, Jagdish Singh","doi":"10.1081/CUS-100000336","DOIUrl":"https://doi.org/10.1081/CUS-100000336","url":null,"abstract":"Fuel system maintenance usually requires direct, prolonged exposure to fuel. Thus, both military and commercial aircraft workers are at risk of dermal exposure and toxicity from JP-8 jet fuel. At present, there are no standards for U.S. Air Force personnel regarding dermal exposure to jet fuel. Hence, there are needs for data and approaches to understand the human hazard from dermal exposure to JP-8. In this study, we investigated the alteration in porcine skin at ultrastructural level, after a 24-h exposure to JP-8, with the help of transmission electron microscopy (TEM). Many ultrastructural modifications were noticed in the photomicrographs. Large-scale expansion in intercellular lipid domains of stratum corneum and disruption in its structural integrity; alteration in configuration of basal cells; rupture of hemidesmosomes and desmosomes; and diminished dendritic processes in Langerhans cells were observed. It is concluded that JP-8 exposure can cause alteration in skin anatomy, which may lead to dermal toxicity. Further studies are required to determine comparative damages incurred by individual components of JP-8.","PeriodicalId":17547,"journal":{"name":"Journal of Toxicology-cutaneous and Ocular Toxicology","volume":"26 1","pages":"11 - 21"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89796499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In vitro percutaneous absorption methods have become widely used for measuring the absorption of compounds that come in contact with skin. Safety evaluations of toxic chemicals frequently rely on in vitro studies for human permeation data. Animal data must be used cautiously for estimating human absorption due to differences in barrier properties of animal and human skin (1). In vitro absorption studies can also be used to measure skin metabolism if viable skin is obtained for the study and if the viability is maintained in the diffusion cells (2). The in vitro system allows for the isolation of skin so that metabolism of the organ can be distinguished from systemic metabolism. Important considerations is conducting in vitro absorption studies are discussed in the following sections.
{"title":"Determination of percutaneous absorption by in vitro techniques","authors":"R. Bronaugh, H. Hood, M. Kraeling, J. Yourick","doi":"10.1081/CUS-120001867","DOIUrl":"https://doi.org/10.1081/CUS-120001867","url":null,"abstract":"In vitro percutaneous absorption methods have become widely used for measuring the absorption of compounds that come in contact with skin. Safety evaluations of toxic chemicals frequently rely on in vitro studies for human permeation data. Animal data must be used cautiously for estimating human absorption due to differences in barrier properties of animal and human skin (1). In vitro absorption studies can also be used to measure skin metabolism if viable skin is obtained for the study and if the viability is maintained in the diffusion cells (2). The in vitro system allows for the isolation of skin so that metabolism of the organ can be distinguished from systemic metabolism. Important considerations is conducting in vitro absorption studies are discussed in the following sections.","PeriodicalId":17547,"journal":{"name":"Journal of Toxicology-cutaneous and Ocular Toxicology","volume":"37 1","pages":"423 - 427"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79051749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
From the 1950s through the 1970s, the rate of uptake of a chemical through the skin was generally estimated from studies of humans using radiolabeled compounds (1). More recently, estimates of dermal absorption have been made using animal (in vivo or in vitro) or human (in vitro) skin. In vivo percutaneous absorption in animals is usually determined by measuring radioactivity in blood and excreta following a topical application of the labeled compound. This indirect method of determining percutaneous absorption provides an estimate of the total absorbed dose, but often fails to reveal information on absorption kinetics. To date, the only way to determine the absolute bioavailability of a topically applied compound is to compare the concentrations in blood or urine following topical and intravenous administration (2). Since blood levels may be very low in these situations, this practice is often restricted by the sensitivity limits of the assay or analysis. As an alternative to conducting radiotracer studies, a new, real-time breath analysis system coupled with physiologically based pharmacokinetic (PBPK) modeling has been developed to determine percutaneous absorption in rats and humans in vivo (3). With this system, a topical dose of a compound can be applied to a specified skin surface area, and the breath analysis system can be used to monitor the concentration of that compound and/or its metabolites in the exhaled breath. A PBPK model, modified to describe the dermal exposure, can than be used to determine the skin permeability constant under various exposure situations.
{"title":"An innovative method to determine percutaneous absorption: Real-time breath analysis and physiologically based pharmacokinetic modeling","authors":"K. Thrall, T. Poet, R. Corley","doi":"10.1081/CUS-120001873","DOIUrl":"https://doi.org/10.1081/CUS-120001873","url":null,"abstract":"From the 1950s through the 1970s, the rate of uptake of a chemical through the skin was generally estimated from studies of humans using radiolabeled compounds (1). More recently, estimates of dermal absorption have been made using animal (in vivo or in vitro) or human (in vitro) skin. In vivo percutaneous absorption in animals is usually determined by measuring radioactivity in blood and excreta following a topical application of the labeled compound. This indirect method of determining percutaneous absorption provides an estimate of the total absorbed dose, but often fails to reveal information on absorption kinetics. To date, the only way to determine the absolute bioavailability of a topically applied compound is to compare the concentrations in blood or urine following topical and intravenous administration (2). Since blood levels may be very low in these situations, this practice is often restricted by the sensitivity limits of the assay or analysis. As an alternative to conducting radiotracer studies, a new, real-time breath analysis system coupled with physiologically based pharmacokinetic (PBPK) modeling has been developed to determine percutaneous absorption in rats and humans in vivo (3). With this system, a topical dose of a compound can be applied to a specified skin surface area, and the breath analysis system can be used to monitor the concentration of that compound and/or its metabolites in the exhaled breath. A PBPK model, modified to describe the dermal exposure, can than be used to determine the skin permeability constant under various exposure situations.","PeriodicalId":17547,"journal":{"name":"Journal of Toxicology-cutaneous and Ocular Toxicology","volume":"158 1","pages":"513 - 521"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75759386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lourdes B. Nonato, Y. Kalia, A. Naik, C. Lund, R. Guy
The skin, one of the largest organs of the body, functions as a protective and regulatory barrier between the body and the external environment. At birth, infants must make the transition from a fluid intrauterine environment to dry, extrauterine life. Full-term infants, born at 40 weeks of gestation, make the transition with a competently formed barrier. However, the skin of the premature neonate comprises as much as 13% of the body weight, compared to only 3% of the body weight of an adult (1). In addition, the surface area to body weight ratio of the neonate is four times that of adults (2). Thus, the immaturity of the skin has numerous ramifications for the neonate, including ineffective thermoregulation (3), fluid imbalance (4), percutaneous absorption of toxins (2), tissue injury (5), infection (6), and delayed healing (7). Within the last decade, new technologies have changed the caretaking practices of the premature neonate; advances in respirator design, monitor technology, reduction of blood volume required for specialized tests, and the sophistication of new diagnostic techniques have all contributed to increasing the chances of survival of the premature neonate (8). Nevertheless, much remains to be learned about the complex extrauterine skin development of these neonates.
{"title":"The development of skin barrier function in the neonate","authors":"Lourdes B. Nonato, Y. Kalia, A. Naik, C. Lund, R. Guy","doi":"10.1081/CUS-120001864","DOIUrl":"https://doi.org/10.1081/CUS-120001864","url":null,"abstract":"The skin, one of the largest organs of the body, functions as a protective and regulatory barrier between the body and the external environment. At birth, infants must make the transition from a fluid intrauterine environment to dry, extrauterine life. Full-term infants, born at 40 weeks of gestation, make the transition with a competently formed barrier. However, the skin of the premature neonate comprises as much as 13% of the body weight, compared to only 3% of the body weight of an adult (1). In addition, the surface area to body weight ratio of the neonate is four times that of adults (2). Thus, the immaturity of the skin has numerous ramifications for the neonate, including ineffective thermoregulation (3), fluid imbalance (4), percutaneous absorption of toxins (2), tissue injury (5), infection (6), and delayed healing (7). Within the last decade, new technologies have changed the caretaking practices of the premature neonate; advances in respirator design, monitor technology, reduction of blood volume required for specialized tests, and the sophistication of new diagnostic techniques have all contributed to increasing the chances of survival of the premature neonate (8). Nevertheless, much remains to be learned about the complex extrauterine skin development of these neonates.","PeriodicalId":17547,"journal":{"name":"Journal of Toxicology-cutaneous and Ocular Toxicology","volume":"50 1","pages":"335 - 367"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79797141","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The skin is a portal of entry and the largest organ of the body. It has been shown to contain the major enzymes found in other tissues of the body (1). Topically applied compounds may be metabolized in skin resulting in altered pharmacologic or toxicologic activity. The metabolism of benzo[a]pyrene applied to mouse skin floating in an organ culture demonstrated the potential importance of metabolism of chemicals during percutaneous absorption (2). A flow-through diffusion cell was subsequently developed to aid in quantitating skin absorption and metabolism (3). Viability of skin in the diffusion cell, which was assessed by light microscopy, was found to be maintained for at least 17 h (3). The viability of pig skin was maintained in flow-through cells by using tissue culture media; skin-mediated hydrolysis of diethyl malonate was observed (4). The suitability of these conditions to maintain skin viability was assessed in initial studies by the ability to graft the skin to nude mice (5).
{"title":"Cutaneous metabolism during in vitro percutaneous absorption","authors":"R. Bronaugh, M. Kraeling, J. Yourick, H. Hood","doi":"10.1081/CUS-120001860","DOIUrl":"https://doi.org/10.1081/CUS-120001860","url":null,"abstract":"The skin is a portal of entry and the largest organ of the body. It has been shown to contain the major enzymes found in other tissues of the body (1). Topically applied compounds may be metabolized in skin resulting in altered pharmacologic or toxicologic activity. The metabolism of benzo[a]pyrene applied to mouse skin floating in an organ culture demonstrated the potential importance of metabolism of chemicals during percutaneous absorption (2). A flow-through diffusion cell was subsequently developed to aid in quantitating skin absorption and metabolism (3). Viability of skin in the diffusion cell, which was assessed by light microscopy, was found to be maintained for at least 17 h (3). The viability of pig skin was maintained in flow-through cells by using tissue culture media; skin-mediated hydrolysis of diethyl malonate was observed (4). The suitability of these conditions to maintain skin viability was assessed in initial studies by the ability to graft the skin to nude mice (5).","PeriodicalId":17547,"journal":{"name":"Journal of Toxicology-cutaneous and Ocular Toxicology","volume":"6 1","pages":"271 - 277"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80195362","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Bellot, M. Palmero, C. García-Cabanes, M. Sanz, A. Orts
Retinal pigmented epithelium (RPE) is an ocular tissue that performs several important functions such as light perception and phagocytosis. This study investigated the effects of hypoxia and serum and glucose deprivation of the RPE tissue. The possible protective effects of antioxidants were also studied by determining cell viability, ATP content, and DNA fragmentation. The results demonstrate that antioxidants can protect RPE tissue from death through the inhibition of some mechanisms that lead to cellular apoptosis.
{"title":"EFFECT OF HYPOXIC STRESS IN RPE CELLS: INFLUENCE OF ANTIOXIDANT TREATMENTS","authors":"J. Bellot, M. Palmero, C. García-Cabanes, M. Sanz, A. Orts","doi":"10.1081/CUS-100000338","DOIUrl":"https://doi.org/10.1081/CUS-100000338","url":null,"abstract":"Retinal pigmented epithelium (RPE) is an ocular tissue that performs several important functions such as light perception and phagocytosis. This study investigated the effects of hypoxia and serum and glucose deprivation of the RPE tissue. The possible protective effects of antioxidants were also studied by determining cell viability, ATP content, and DNA fragmentation. The results demonstrate that antioxidants can protect RPE tissue from death through the inhibition of some mechanisms that lead to cellular apoptosis.","PeriodicalId":17547,"journal":{"name":"Journal of Toxicology-cutaneous and Ocular Toxicology","volume":"173 1","pages":"29 - 38"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86803572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Federal Food, Drug, and Cosmetic Act (FD&C Act) establishes substantially different regulatory requirements in the United States for cosmetics and drugs. This chapter traces the history of U.S. regulatory policy for these two categories of products, discusses the application of U.S. law to products that fall within both categories at the same time (i.e., cosmetic drugs), and considers potential strategies for resolving the long-standing concern that the drug provisions of the Act impose overly stringent requirements on cosmetic drugs.
{"title":"The legal distinction in the United States between a cosmetic and a drug","authors":"P. Hutt","doi":"10.1081/CUS-120001858","DOIUrl":"https://doi.org/10.1081/CUS-120001858","url":null,"abstract":"The Federal Food, Drug, and Cosmetic Act (FD&C Act) establishes substantially different regulatory requirements in the United States for cosmetics and drugs. This chapter traces the history of U.S. regulatory policy for these two categories of products, discusses the application of U.S. law to products that fall within both categories at the same time (i.e., cosmetic drugs), and considers potential strategies for resolving the long-standing concern that the drug provisions of the Act impose overly stringent requirements on cosmetic drugs.","PeriodicalId":17547,"journal":{"name":"Journal of Toxicology-cutaneous and Ocular Toxicology","volume":"401 1","pages":"203 - 219"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76460256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"PRELIMINARY RESULTS WITH A NEW SOFT PLIABLE DOG INTRAOCULAR IMPLANT: THE CANI/JAG","authors":"J. Gaiddon, J. Gaiddon, P. Lallement","doi":"10.1081/CUS-100000340","DOIUrl":"https://doi.org/10.1081/CUS-100000340","url":null,"abstract":"","PeriodicalId":17547,"journal":{"name":"Journal of Toxicology-cutaneous and Ocular Toxicology","volume":"27 1","pages":"49 - 51"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73586482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Unique biochemical and immunological events dictate the complex cyclic growth and differentiation patterns of hair follicles and their associated sebaceous glands (1), structures that are collectively referred to as pilosebaceous units. Once regarded as mere evolutionary remnants, hair follicles and sebaceous glands have been recognized increasingly as significant pathways for percutaneous transport (2). Percutaneous transport routes via the lipoidal domains of the stratum corneum have been well established (3,4), whereas comparatively less is known about the specific roles of hair follicles and sebaceous glands. Determination of the roles of these structures is complicated by the lack of adequate animal models and methodologies that can distinctly distinguish follicular and stratum corneumpathways.Moreover, it may be possible that a topically applied compound traverses more than one pathway simultaneously. The stratum corneum is acknowledged not only as the main barrier to skin penetration, but also as the major permeation pathway. The tightly packed, semicrystalline intercellular lipid domains and the extremely compact corneocytes of the stratum corneum create a barrier highly resistant to percutaneous transport (3,4). Modulation of stratum corneum lipid fluidity by topical agents has been thoroughly studied and is generally acknowledged as the major mechanism of percutaneous delivery (5). Passive percutaneous transport depends on several factors, including penetrant lipophilicity, charge, and molecular size (6). The upper limit of molecular size for permeation through the stratum corneum is still unknown. Early suggestions of a follicular pathway were based on the hypothesis that hair follicles act as shunts, resulting in the rapid transport of ions and large polar molecules. Scheuplein (7) and Scheuplein et al. (8) first described transient follicular delivery for small polar molecules and large polar steroids that ordinarily would not be expected to traverse the skin rapidly due to their charge or restrictive molecular size. Feldmann and Maibach (9) and Maibach et al. (10) observed increases in percutaneous transport through skin areas with greatest follicular densities in both animals and humans, which also hinted at the possibility of follicular delivery.
{"title":"Percutaneous drug delivery to the hair follicle","authors":"A. Lauer","doi":"10.1081/CUS-120001871","DOIUrl":"https://doi.org/10.1081/CUS-120001871","url":null,"abstract":"Unique biochemical and immunological events dictate the complex cyclic growth and differentiation patterns of hair follicles and their associated sebaceous glands (1), structures that are collectively referred to as pilosebaceous units. Once regarded as mere evolutionary remnants, hair follicles and sebaceous glands have been recognized increasingly as significant pathways for percutaneous transport (2). Percutaneous transport routes via the lipoidal domains of the stratum corneum have been well established (3,4), whereas comparatively less is known about the specific roles of hair follicles and sebaceous glands. Determination of the roles of these structures is complicated by the lack of adequate animal models and methodologies that can distinctly distinguish follicular and stratum corneumpathways.Moreover, it may be possible that a topically applied compound traverses more than one pathway simultaneously. The stratum corneum is acknowledged not only as the main barrier to skin penetration, but also as the major permeation pathway. The tightly packed, semicrystalline intercellular lipid domains and the extremely compact corneocytes of the stratum corneum create a barrier highly resistant to percutaneous transport (3,4). Modulation of stratum corneum lipid fluidity by topical agents has been thoroughly studied and is generally acknowledged as the major mechanism of percutaneous delivery (5). Passive percutaneous transport depends on several factors, including penetrant lipophilicity, charge, and molecular size (6). The upper limit of molecular size for permeation through the stratum corneum is still unknown. Early suggestions of a follicular pathway were based on the hypothesis that hair follicles act as shunts, resulting in the rapid transport of ions and large polar molecules. Scheuplein (7) and Scheuplein et al. (8) first described transient follicular delivery for small polar molecules and large polar steroids that ordinarily would not be expected to traverse the skin rapidly due to their charge or restrictive molecular size. Feldmann and Maibach (9) and Maibach et al. (10) observed increases in percutaneous transport through skin areas with greatest follicular densities in both animals and humans, which also hinted at the possibility of follicular delivery.","PeriodicalId":17547,"journal":{"name":"Journal of Toxicology-cutaneous and Ocular Toxicology","volume":"5 1","pages":"475 - 495"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75201448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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