Adsorption dermal

The dermal adsorption of DEBT in humans has been studied in the Netherlands by appHcation of DEBT as undiluted technical material or as 15% solutions in alcohol. Labeled material was recovered from the skin, and absorption of DEBT was indicated by the appearance of label in urine after two hours of skin exposure. About 5—8% of the appHed treatments was recovered as metaboHtes from urine, and excretion of metaboHtes in the urine came to an end four hours after exposure ended. DEBT did not accumulate in the skin, and only a small (less than 0.08%) amount ended up in feces. Curiously, less has been absorbed through skin from 100% DEBT appHcation (3—8%, mean of 5.6%) than from 15% alcohol appHcation (4—14%, mean of 8.4%). These results have been described as consistent with previous absorption/metaboHsm studies using guinea pigs, rats, and hairless dogs. Other pubHcations on DEBT toxicology have been cited (92). 

Diphtheria (adsorbed) Cultures of C. diphtheriae in liquid medium 1 Separation and concentration of toxin 2 Conversion of toxin to toxoid 3 Adsorption of toxoid to adjuvant 3+3 quantal assay in guinea-pigs using intra-dermal challenge Inoculation of guinea-pigs to exclude residual toxin... 

The title compound 188, currently under development for the treatment of acne, psoriasis and photoaging via a topical application, has been synthesized161 in two steps by reacting carboxyl-[14C]vitamin A, 189, with ethyl chloroformate and subsequent treatment of the mixed anhydride 190 with acetamidophenol in the presence of a catalytic amount of 4-dimethylaminopyridine (equation 68), Carbon- 14-labelled compound was needed to investigate its metabolism and the extent of systematic adsorption of 188 after dermal application. 

Bioavailability from Environmental Media. Carbon tetrachloride can be absorbed following inhalation, oral, or dermal exposure. No data were located regarding the potential effects of environmental media (air, water, soil) on the absorption of carbon tetrachloride. Flowever, since soil adsorption is considered to be relatively low for carbon tetrachloride, it seems unlikely that soil would have a significant effect on its bioavailability. Additional studies are needed to determine the extent of bioavailability from contaminated air, drinking water, and soil at hazardous waste sites. 

Bunge AL Colorado School of Mines Golden, CO Dermal Adsorption from Soils—Evaluation and Prediction National Institute of Environmental Health Sciences... 

Toxicity The acute oral LD50 and dermal LD50 toxicity of toxaphene in rats are 40 and 600 mg/kg, respectively. Toxaphene is an active nerve poison and interferes with fluxes of cations across nerve cell membranes, which increases neuronal irritability and results in convulsions and seizures. Toxaphene also has been found to damage the lungs, liver, and kidney of animals and humans. Although the dermal adsorption efficiency of toxaphene is less than that of other organochlorines, its absorption is enhanced by fat and fat solvents. Toxaphene has been shown to cause cancer in pregnant animals and to induce birth defects.68... 

Toxicity Parathion is highly toxic by all routes of exposure. Occurrences of human fatalities are due to ingestion, dermal adsorption, and inhalation of parathion. The acute oral LD50 for rats is 2.6 mg/kg, for mice 12.0 mg/kg, and for guinea pigs 10 mg/kg. The acute dermal LD50 for rats is 71 to 76 mg/kg.1,3 9 78,79... 

Data indicate that soil adsorption decreases the dermal bioavailability of benzene. A study in which male rats were treated dermally with 0.004 mg/cm214C-benzene, with or without 1 g of clay or sandy soil, reported benzene absorption half-lives of 3.1, 3.6, and 4.4 hours for pure benzene, sandy soil, and clay soil, respectively (Skowronski et al. 1988). 

Skowronski GA, Turkall RM, Abdel-Rahman MS. 1988. Soil adsorption alters bioavailability of benzene in dermally exposed male rats. Am Ind Hyg Assoc J 49 506-511. 

Bioavailability from Environmental Media. Asbestos fibers are insoluble and are not absorbed in the usual sense after inhalation, oral, or dermal exposure. Most exposures occur either to fibers in air or water, so the effect of matrices such as soil or food are largely unknown. It is possible that adsorption of fibers onto other dust particles could influence the location of deposition in the lung, and might even influence the cellular response to the fibers. Research to determine if this occurs and is of biological significance would be helpful. 

No human or animal studies were found on adsorption, distribution, metabolism, or excretion of titanium tetrachloride. Because of the nature of titanium tetrachloride, it is suggested that the major route of exposure is via inhalation, with the lungs as the major target organ. Dermal exposure can also result where accidental spills have occurred. It has been shown that titanium dioxide was present in the lungs of workers occupationally exposed to titanium tetrachloride. 

Surfactants and solvents are added to commercial pesticides to increase adsorption by targeted species. These chemicals also enhance adsorption through mammalian skin. In a laboratory animal experiment, dermal... 

Bioavailability from Environmental Media. Available absorption kinetics of dinitrophenols following ingestion and dermal contact are discussed in Section 2.3. No experimental or estimated data were located that provide information about the bioavailability of dinitrophenols from natural air, water, and soil. The observation that dinitrophenols are found at least partly in the particulate-sorbed state in the air (Nojima et al. 1983) indicates that their bioavailability from air is <100%. The adsorption of dinitrophenols to soil and sediment depends on the nature of soil and sediment (e.g., organic matter and clay content) and the pH of the medium (Callahan et al. 1979 Kaufman 1976). Therefore, the bioavailability of particle-sorbed dinitrophenols due to desorption from soil and sediment containing a high percent of organic matter and clay may be less than that of the free form (unadsorbed) of dinitrophenol. The bioavailability of dinitrophenols from inhaled air particulates with small particle diameters remains unknown. 

Target levels were established for cleaning equipment surfaces. These levels for normal products were proposed based on a simple evaluation of toxicological data, such as ADI (allowable daily intake) or LD50, and estimates of dermal contact and potential skin adsorption (Table II). 

EXPOSURE ROUTES inhalation or dermal contact manufacture, formulation, application of pesticide pesticide leaching or runoff percutaneous adsorption wastewater effluents... 

EXPOSURE ROUTES contaminated air in pressure treated log homes low levels in drinking water and food contaminated air at wood treatment facilities and lumber mills dermal contact with pressure treated lumber inhalation skin adsorption ingestion eye and skin contact... 

In 1962 in Quebec ( ), the dermal exposure was found to be 6.3 mg/15 min. as a mean of 7 subjects the range was 4.6-7.6. The exposure was determined by the adsorption to forehead and wrist pads. This approximated the long-sleeved regimen where our home gardener received a much lower 0.2-0.3 mg/15 min. for high plants ... 

IP, mouse) 100 mg/kg, (dermal) > 4000 mg/kg poison by IP route mod. toxic by ing. causes eye damage, skin irritation TSCA listed Environmental LC50 (guppy) 40 mg/l nontoxic to bees slow degradation high soil adsorption affinity... 

Monitoring methods for dermal exposure have not been standardized as well as the methods to assess inhalation exposure. Adsorptive pads of activated carbon cloth can be used for monitoring of dermal exposure to organic solvents. Patches are attached on various parts of the body under the clothing and the amounts analyzed are then multiplied with the areas of each body region.Exposure assessment is complicated by the contribution of solvent vapor on the samples. Because the adsorptive surface of activated carbon is much larger than that of the skin, pads will adsorb much more solvents than the skin. However, only exposure to liquid phase is usually significant therefore, the adsorbed vapor should be subtracted from the total mass analyzed. However, this makes the exposure assessment... 

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