Penetration human skin

Coumarin penetrates human skin rapidly and efficiently (see Section 4.1). 

These chloroarsines are effective cytochrome oxidase destroyers, or blood agents. Arsenic seeks to replace calcium in the bones, thus causing bone marrow destruction as the endocrine system is concurrently attacked (Styblo and Thomas, 1997). Many organic radicals penetrate human skin, carrying their compounds with them (Cohen et al, 2006). 

On the other hand, highly lipophilic compounds, such as hormones, can be solubilized via the prodrug approach. For example, the rate of transdermal absorption of the highly lipophilic drug, testosterone, was enhanced over 50-fold by forming water-soluble, yet lipophilic, prodrug ester.f The prodrug testoster-onyl-4-dimethylaminobutyrate was found to penetrate human skin tissue, in vitro, 54 times faster than... 

Ethylene oxide is readily taken up by the lung. At steady state, 20-25% of inhaled ethylene oxide reaching the alveolar space is exhaled as unchanged compound and 75-80% is taken up by the body and metabolized. Aqueous ethylene oxide solutions can penetrate human skin. 

Oxamniquine is an important Third World drug used in the treatment of schistosomiasis (bilharzia). This disease affects an estimated two hundred million people and is contracted by swimming or wading in infected water. The disease is carried by a snail which can penetrate human skin and enter the blood supply. There, it produces eggs which become trapped in organs and tissues, and this in turn leads to the symptoms of the disease. 

The toxicity of nanomaterials is not well understood, and many commentators have expressed concern that the unique properties of nanomaterials maybe associated with unknown risks. Some of the concern is because of the ability of small particles to penetrate Hving tissue. There are conflicting study conclusions on whether inhaled nanoparticles may mimic the action of asbestos in the lungs. Some studies conclude that they do cause inflammation because they can reach the lung structures that exchange oxygen and carbon dioxide from the blood. However, other studies conclude that the results are equivocal. Similarly, titanium dioxide nanoparticles have been the subject of several studies to determine whether or not they can penetrate human skin when they are used in sunscreen formulations. While studies have shown that they do not penetrate beyond the outer layer of skin, the studies have been criticized because they were aU on intact, unabraded healthy adult skin, and so the risks in actual use may not be the same as indicated by those studies. In addition, many formulations contain moisturizers that are designed to penetrate skin, and the effects of these moisturizers on the skin penetration of titanium dioxide nanoparticles are unknown. ... 

Properties Pale yel. liq. sol. in ether sol. > 10 mg/ml in 95% ethanol si. sol. in DMSO insol. in water m.w. 268.27 m.p. 84-86 C b.p. 135 C Toxicology LD50 (oral, rat) 339 mg/kg toxic local irritant photosensitive neurotoxic effects penetrates human skin and is only slowly excreted target organ nerves TSCA listed... 

Hexachlorophene <0.1% and when an alternative preservative has not been shown to be as effective and it may not be used in cosmetics to be applied to mucous membranes Neurotoxic effect and ability to penetrate human skin... 

The decay of Tritium produces He and energy of 18.6 keV is released (5.7 keV is the kinetic energy of the electron, the rest is the energy of the neutrino v). The decay of tritium produces low energy radiation. This radiation is not dangerous because it cannot penetrate human skin (only if inhaled or ingested). 

The filariform larva found in moist soils may be either ingested or penetrate the skin of its host. It is then carried through the circulatory system to the lungs and migrates up the respiratory tree into the digestive tract. The worms feed on intestinal tissue and blood. Some worms may persist in humans as long as nine years. Infestations cause cutaneous reactions, pulmonary lesions, intestinal ulcerations, and anemia. 

Alcohol and alcohol ether sulfates have also been studied to determine their toxicity by percutaneous absorption in rats and guinea pigs [354-356]. Alcohol ether sulfates penetrate in the order of 1 ng/cm2/day and alcohol sulfates are less penetrant by a factor of 10. The surfactant absorbed was metabolized. Since it is known that human skin is less permeable than animal skin, only very small amounts of alcohol or alcohol ether sulfates can be absorbed even in the case of complete body exposure. 

Sartorelli P, Aprea C, Bussani R, et al. 1997. In vitro percutaneous penetration of methyl-parathion from a commercial formulation through the human skin. Occup Environ Med 54 524-525. 

Nickel salts penetrate very slowly into the human skin [272-274] and little enhancement by sweat or detergents has been observed [272]. In addition, an initial rapid phase of uptake through the sweat ducts and hair follicles has been suggested [271, 275],... 

Even nickel ions under occlusion penetrate the human skin very slowly, with a lag-time of about 50 h [276] there is a reversible binding of nickel to epidermis [278]. Nickel permeation is also highly dependent on the choice of vehicle [277] a higher penetration rate of metal ions from a solution than from a semisolid suspension has been reported [279],... 

The contact of nanoparticles with human skin is another concern when considering the potential human health risks of CNTs (Nohynek et al., 2007). It can penetrate the skin, reach to bloodstream, and be taken by cells, tissues, and organs. For example, if gloves are not worn when handling CNTs, dermal toxicity can take place and very fine nanoparticles might also penetrate the skin through resulting in transdermal delivery. 

N. Leveque, S. Makki, J. Hadgraft, and P. Humbert. Comparison of Franz cells and microdialysis for assessing salicylic acid penetration through human skin. Int. J. Pharm. 269 323-328 (2004). 

I. H. Pitman and S. J. Rostas. A comparison of frozen and reconstituted cattle and human skin as barriers to drug penetration. J. Pharm. Sci. 71 427-430 (1982). 

Keywords Skin permeability Percutaneous absorption Skin penetration Mathematical model Quantitative structure-activity relationships Permeability coefficient Human skin... 

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