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In vitro dermal absorption of a metalworking fluid additive: dicyclohexylamine (DCHA).

Linthicum-A; Koivisto-E; Brooks-JD; Baynes-RE
Toxicologist 2012 Mar; 126(Suppl 1):123
Dicyclohexylamine (DCHA) is commonly used in the metalworking industry to prevent corrosion of fabricated materials. There is no published information describing the dermal absorption of DCHA in metalworking fluid (MWF) formulations. Machine workers are most likely to be exposed to DCHA by the dermal route. The objective of this research was to quantify the dermal absorption of DCHA in vitro using porcine skin because of its similarity to human skin both anatomically and biochemically. DCHA was applied to pig skin in water and in 3 generic MWF formulations commonly used in industry: Soluble (SO), synthetic (SYN), and semi-synthetic (SS) oil. Dermatomed pig skin (n=4) was loaded onto a flow-through diffusion cell system with individual dose areas of 0.64 cm2 and perfused with media containing 4.5% bovine serum albumin for 8h to mimic occupational exposure conditions. Pig skin was dosed with 5-10% DCHA in 7 vehicles: Water, water + 5% SO, SYN, or SS oil; or neat SO, SYN, or SS oil. Dermal absorption of DCHA was similar between SO, SYN, and SS oil mixed with water, as well as between neat SO, SYN, and SS oil. Dermal absorption of DCHA from water + SS (0.08%) > water + SO (0.02%) > water + SYN (0.005%). Dermal absorption of DCHA from neat SS (0.11%) > neat SYN (0.09%) > neat SO (0.03%). The highest overall dermal absorption was at 1.4% from the water vehicle. These results suggest that water facilitates the dermal absorption of DCHA across skin whereas DCHA in MWFs may partition more with the vehicle due to its partitioning behavior. In conclusion, the varied dermal absorption of DCHA across MWF formulations must be taken into account within the machining industry and MWF manufacturing as repeated occupational exposure to this metalworking fluid additive may prove to be detrimental to human health.
Health-hazards; Cyclohexylamines; Metalworking-fluids; Skin-absorption; Quantitative-analysis; In-vitro-study; Exposure-assessment; Exposure-levels; Exposure-methods; Laboratory-animals; Laboratory-testing; Oil-dermatitis; Oils; Synthetics; Fluid-mechanics; Fluids
Publication Date
Document Type
Funding Amount
Funding Type
Fiscal Year
Identifying No.
Grant-Number-R01-OH-003669; B04252012
Priority Area
Manufacturing; Disease and Injury: Allergic and Irritant Dermatitis
Source Name
The Toxicologist. Society of Toxicology 51st Annual Meeting and ToxExpo, March 11-15, 2012, San Francisco, California
Performing Organization
North Carolina State University, Raleigh, North Carolina
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division