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Hopf NB, De Luca HP, Borgatta M, Koch HM, Pälmke C, Benedetti M, Berthet A, Reale E. Human skin absorption of three phthalates. Toxicol Lett 2024; 398:38-48. [PMID: 38880306 DOI: 10.1016/j.toxlet.2024.05.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 05/01/2024] [Accepted: 05/30/2024] [Indexed: 06/18/2024]
Abstract
Population studies reveal widespread exposure to phthalates. Understanding their absorption, distribution, metabolism, and excretion is vital to reduce exposure. However, data on skin absorption remain limited. We thus aim to characterize the skin permeation of three phthalates in a mixture, neat or in emulsion; di(2-ethylhexyl) phthalate (d4-DEHP), dibutyl phthalate (d4-DBP), and diethyl phthalate (d4-DEP), by comparing in vitro human skin (800 µm) permeation (24 hours) results using flow-through diffusion cells with urine results obtained from volunteers exposed to the same mixture applied to a forearm (40 cm2). Metabolites were analyzed in receptor fluids and urine. Phthalates crossed the skin barrier and metabolized into monoesters before elimination. Increased permeation was observed for phthalates in emulsion compared to neat substances, with polyethylene glycol (PEG) in the receptor fluid enhancing emulsion permeation, but not affecting neat substances. In vitro results mirrored in vivo findings: DEP showed rapid permeation (J: ∼2 ug/cm2/h) and urinary excretion peaking at six hours post-application, whereas DBP exhibited slower kinetics (J: ∼0.1 ug/cm2/h), with a urinary peak at 15-17 hours post-application. DEHP had minimal permeation (J: ∼0.0002 ug/cm2/h) with no observable urinary peak. These findings underscore the importance of comprehending phthalate skin absorption for effective exposure mitigation strategies.
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Affiliation(s)
- Nancy B Hopf
- Center for Primary Care and Public Health (Unisanté), University of Lausanne, Route de la Corniche 2, Epalinges, Lausanne 1066, Switzerland; Swiss Center for Applied Human Toxicology (SCAHT), Basel.
| | - Hélène P De Luca
- Center for Primary Care and Public Health (Unisanté), University of Lausanne, Route de la Corniche 2, Epalinges, Lausanne 1066, Switzerland; Swiss Center for Applied Human Toxicology (SCAHT), Basel
| | - Myriam Borgatta
- Center for Primary Care and Public Health (Unisanté), University of Lausanne, Route de la Corniche 2, Epalinges, Lausanne 1066, Switzerland; Swiss Center for Applied Human Toxicology (SCAHT), Basel
| | - Holger M Koch
- Institute for Prevention and Occupational Medicine of the German Social Accident Insurance - Institute of the Ruhr-University Bochum (IPA), Bochum, Germany
| | - Claudia Pälmke
- Institute for Prevention and Occupational Medicine of the German Social Accident Insurance - Institute of the Ruhr-University Bochum (IPA), Bochum, Germany
| | - Manon Benedetti
- Center for Primary Care and Public Health (Unisanté), University of Lausanne, Route de la Corniche 2, Epalinges, Lausanne 1066, Switzerland
| | - Aurélie Berthet
- Center for Primary Care and Public Health (Unisanté), University of Lausanne, Route de la Corniche 2, Epalinges, Lausanne 1066, Switzerland; Swiss Center for Applied Human Toxicology (SCAHT), Basel
| | - Elena Reale
- Center for Primary Care and Public Health (Unisanté), University of Lausanne, Route de la Corniche 2, Epalinges, Lausanne 1066, Switzerland; Swiss Center for Applied Human Toxicology (SCAHT), Basel
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Gustafsson E, Hellsing MS, Rennie AR, Welbourn RJL, Campana M, Hughes A, Li P, Bowden TM. Understanding interactions of plasticisers with a phospholipid monolayer. SOFT MATTER 2024; 20:2892-2899. [PMID: 38465518 DOI: 10.1039/d3sm01611k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
The use of DEHP (diethylhexyl phthalate) is now banned for most applications in Europe; the exception is for blood bags, where its toxicity is overshadowed by its ability to extend the storage life of red blood cells. Another plasticiser, BTHC (butanoyl trihexyl citrate), is used in paediatric blood bags but does not stabilise blood cells as effectively. Interactions between plasticisers and lipids are investigated with a phospholipid, DMPC, to understand the increased stability of blood cells in the presence of DEHP as well as bioaccumulation and identify differences with BTHC. Mixed monolayers of DMPC and DEHP or BTHC were studied on Langmuir troughs where surface pressure/area isotherms can be measured. Neutron reflection measurements were made to determine the composition and structure of these mixed layers. A large amount of plasticiser can be incorporated into a DMPC monolayer but once an upper limit is reached, plasticiser is selectively removed from the interface at high surface pressures. The upper limit is found to occur between 40-60 mol% for DEHP and 20-40 mol% for BTHC. The areas per molecule are also different with DEHP being in the range of 50-100 Å2 and BTHC being 65-120 Å2. Results indicate that BTHC does not fit as well as DEHP in DMPC monolayers which could help explain the differences observed with regards to the stability of blood cells.
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Affiliation(s)
- Emil Gustafsson
- Department of Chemistry, Ångström Laboratory, Uppsala University, Box 538, 752 37 Uppsala, Sweden.
| | - Maja S Hellsing
- RISE Research Institutes of Sweden, Box 5604, 114 86 Stockholm, Sweden
| | - Adrian R Rennie
- Department of Chemistry, Ångström Laboratory, Uppsala University, Box 538, 752 37 Uppsala, Sweden.
- Centre for Neutron Scattering, Ångström Laboratory, Uppsala University, Box 538, 752 37 Uppsala, Sweden
| | - Rebecca J L Welbourn
- ISIS Pulsed Neutron and Muon Facility, Rutherford Appleton Laboratory, Didcot, Oxfordshire, OX11 0QX, UK
| | - Mario Campana
- ISIS Pulsed Neutron and Muon Facility, Rutherford Appleton Laboratory, Didcot, Oxfordshire, OX11 0QX, UK
| | - Arwel Hughes
- ISIS Pulsed Neutron and Muon Facility, Rutherford Appleton Laboratory, Didcot, Oxfordshire, OX11 0QX, UK
| | - Peixun Li
- ISIS Pulsed Neutron and Muon Facility, Rutherford Appleton Laboratory, Didcot, Oxfordshire, OX11 0QX, UK
| | - Tim Melander Bowden
- Department of Chemistry, Ångström Laboratory, Uppsala University, Box 538, 752 37 Uppsala, Sweden.
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Taoka Y, Asmaa Saari R, Kida T, Yamaguchi M, Matsumura K. Enhancing the Mechanical Properties of Poly(vinyl alcohol) Fibers by Lithium Iodide Addition. ACS OMEGA 2023; 8:32623-32634. [PMID: 37720794 PMCID: PMC10500668 DOI: 10.1021/acsomega.3c03280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 08/02/2023] [Indexed: 09/19/2023]
Abstract
The effect of lithium iodide (LiI) on the mechanical strength, properties, and molecular orientation of poly(vinyl alcohol) (PVA) fibers spun by wet spinning and then heat-stretched was studied. The stretchability of LiI-PVA fibers was improved, and the rupture during stretching was suppressed compared to PVA fibers. In addition, the tensile strength and elastic modulus of the thermally stretched fibers have been significantly improved. It was also found that the addition of LiI improves the molecular orientation of PVA. This was achieved because LiI reduced the hydrogen bonds between the molecular chains of PVA, resulting in reduced crystallinity. Most of the LiI in the fiber could be removed by a coagulation bath and washing during the spinning process. This means that LiI is eventually removed, and the heat-treatment strengthens the hydrogen bonds, resulting in excellent mechanical strength.
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Affiliation(s)
- Yusuke Taoka
- School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1211, Japan
| | - Riza Asmaa Saari
- School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1211, Japan
| | - Takumitsu Kida
- School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1211, Japan
| | - Masayuki Yamaguchi
- School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1211, Japan
| | - Kazuaki Matsumura
- School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1211, Japan
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