Albumin adducts and urinary metabolites resulting from occupational exposure to 1,5-naphthalene diisocyanate
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University of Würzburg, Würzburg, Germany (Department of Toxicology)
Institute of Environmental and Occupational Toxicology, Airolo, Switzerland
University of Munich, Munich, Germany (Walther-Straub-Institute of Pharmacology and Toxicology)
Online publication date: 2017-04-20
Corresponding author
Gabriele Sabbioni   

Institute of Environmental and Occupational Toxicology, Casella Postale 108, CH-6780 Airolo, Switzerland
Int J Occup Med Environ Health 2017;30(4):579–591
Objectives: 1,5-Naphthalene diisocyanate (NDI) is used in the plastic industry as a curing agent. 1,5-Naphthalene diisocyanate is classified as a sensitizing agent. The objective of this study has been to develop biomonitoring methods for the evaluation of exposure to NDI. Material and Methods: We obtained blood and urine samples from a group of 20 male workers exposed to NDI. The workers answered a questionnaire about their exposure history, job description, the number of years with the company and the time spent working with NDI over the 10 days of the study. Total plasma, albumin, and urine were analyzed for the presence of 1,5-naphthalenediamine (NDA) after acid hydrolysis using gas chromatography-mass spectrometry (GC-MS). Results: 1,5-Naphthalenediamine was found in about 60% of the samples obtained from the workers. 1,5-Naphthalenediamine was obtained after acid hydrolysis of plasma, albumin, and urine at levels up to 1.5 pmol NDA/mg of plasma proteins, 1.15 pmol NDA/mg of albumin, and 55.3 pmol NDA/ml of urine, respectively. Conclusions: 1,5-Naphthalenediamine found in urine correlates best with the plasma levels (r = 0.91, p < 0.01). The albumin-adduct levels did not correlate with the NDI-specific immunoglobulin E (IgE) or total IgE present in the workers. The adduct and metabolite levels correlate with the air levels of NDI. Int J Occup Med Environ Health 2017;30(4):579–591