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Experimental Asbestosis
Published in Joan Gil, Models of Lung Disease, 2020
The methods and techniques developed for the study of asbestos have been adapted for the investigation of the biological effects of other mineral fibers. These have included synthetic mineral fibers both vitreous and crystalline, derived from glass, slag, volcanic rock, and ceramic materials, and the fibrous clay minerals: palygorskite, sepiolite, and anthophyllite. Most interesting so far, of these investigations has been the recognition of the zeolite fibre erionite as the cause of the devastating incidence of mesotheliomas in the Urgup region of Cappadocia in central Turkey. It has been possible to confirm by experimental study the sinister effects of exposure to the finer erionite fibers. This is the only dust in which we have been able to produce a 100% tumor incidence using both the inhalation and implantation techniques.
Microneedles for transdermal drug delivery using clay-based composites
Published in Expert Opinion on Drug Delivery, 2022
Farzaneh Sabbagh, Beom Soo Kim
Sepiolite, a non-planar hydrated magnesium silicate clay mineral with the largest specific surface area among nonmetallic minerals, has a fibrous structure and a unique pore structure. This mineral has the strongest adsorption power among all clay materials. It has one octahedral sheet in the middle, and two tetrahedral sheets of silicon and oxygen. The octahedral sheet remains infinite in two dimensions or discontinuities, whereas the tetrahedral sheet is periodically inverted along the β-axis. This regular inversion leads to the development of long channels through which organic molecules and water can be absorbed. Sepiolite has been used in drug delivery systems to increase drug solubility [78].
Clay nanoparticles as pharmaceutical carriers in drug delivery systems
Published in Expert Opinion on Drug Delivery, 2021
Jiani Dong, Zeneng Cheng, Songwen Tan, Qubo Zhu
Sepiolite(SEP), with a fibrous structure either, is a non-planar hydrated magnesium silicate clay mineral with the unique content pore structure and the largest specific surface area among nonmetallic minerals. It is recognized as the clay mineral with the strongest adsorption capacity [83]. The crystal structure of sepiolite is roughly the same as palygorskite, which is a kind of hydrated magnesium silicate with a layered chain structure. And it has two tetrahedral sheets of silicon and oxygen and one octahedral sheet in the middle. The tetrahedral sheets are periodically inverted along the B-axis, while the octahedral sheet remains infinite in two dimensions or discontinuities(Figure 2 (e)). This periodic inversion results in the formation of long channels, through which water and organic molecules can be absorbed [84]. SEP is often used in drug delivery systems to increase drug solubility. For example, praziquantel(PZQ), used to treat the human schistosomiasis, is a drug of low solubility and high permeability. The solubility of PZQ can be increased by embedding it in sepiolite channels [85]. Cyclodextrin (CDs) and SEP were combined as drug carriers to load the Biopharmaceutical Classification System (BCS) class IV drug (low solubility and permeability) hydrochlorothiazide (HCT), and the solubility increased about 12 times than the drug alone [86]. Mura et al [87]. also chose cyclodextrin [88]-nanoclay complexes as drug vehicles to load a poorly water-soluble anti-inflammatory drug oxaprozin (OXA). They compared the adsorption equilibrium of three different clay minerals (sepiolite, attapulgite, and bentonite) and finally chose sepiolite for its greater adsorption power toward OXA. Dissolution studies had also shown that CD-SEP complexes could significantly improve the solubility of OXA.