Dermal absorption of N,N-dimethylacetamide in human volunteers

T. Nomiyama, K. Omae, C. Ishizuka, T. Yamauchi, Y. Kawasumi, K. Yamada, H. Endoh, H. Sakurai

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Abstract

Objectives: We investigated the potential for the dermal absorption of N,N-dimethylacetamide (DMAC: CAS No. 127-19-5) vapor, the biological half-life of N-methylacetamide (NMAC) in urine as the biological exposure item of DMAC, and the adjustment method for urinary concentrations. Methods: Twelve healthy male volunteers (mean age 25.2 years, range 21-43 years) were exposed to DMAC for 4 h on two occasions at intervals of 96 h or above. Each volunteer sat inside a whole-body-type exposure chamber for the dermal exposure experiment or outside the chamber for the inhalation exposure experiment. The temperature and relative humidity in the chamber were controlled at approximately 26°C and 40% in order to keep the skin (90% naked) of the volunteers dry. DMAC concentrations were 6.1 ± 1.3 ppm for dermal exposure and 6.1 ± 1.3 ppm for inhalation exposure. Urine samples were collected from 0 h through 36 h and at 48 h and 72 h after the exposure. Extrapolations from exposure concentrations for 4 h to 10 ppm for 8 h were performed. Results: Mean dermal absorption was estimated to be 40.4% of the total DMAC uptake. The biological half-lives of urinary NMAC were 9.0 ± 1.4 h and 5.6 ± 1.3 h via skin and lung, respectively. Mean NMAC in urine just after 5 consecutive workdays (8 h/day) at 10 ppm DMAC exposure was assumed to be 33.7 mg/g · Cr (18.6-70.0 mg/g · Cr). Creatinine-adjusted NMAC concentration in urine for each volunteer within 12 h after the exposure was more closely correlated with the total excretion amount of NMAC up to 36 h than with urinary-volume-adjusted or specific-gravity-adjusted NMAC concentration in both the dermal and inhalation exposure experiments. Conclusions: DMAC vapor was significantly absorbed through the skin. Estimated NMAC values indicate that 20 mg/g · Cr NMAC seems to be appropriate as the biological exposure index.

Original languageEnglish
Pages (from-to)121-126
Number of pages6
JournalInternational Archives of Occupational and Environmental Health
Volume73
Issue number2
DOIs
Publication statusPublished - 2000 Mar

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Keywords

  • Biological half-life
  • Biological monitoring
  • Dermal absorption
  • N,N-Dimethylacetamide
  • N-Methylformamide

ASJC Scopus subject areas

  • Public Health, Environmental and Occupational Health

Cite this

Nomiyama, T., Omae, K., Ishizuka, C., Yamauchi, T., Kawasumi, Y., Yamada, K., Endoh, H., & Sakurai, H. (2000). Dermal absorption of N,N-dimethylacetamide in human volunteers. International Archives of Occupational and Environmental Health, 73(2), 121-126. https://doi.org/10.1007/s004200050017