Pharmacokinetics of Triclosan Following Oral Ingestion in Humans

Abstract

The number of personal hygiene products containing triclosan has increased rapidly during the last decade, and triclosan is one of the most common antibacterial compounds used in dentifrices today. However, the extent of triclosan exposure has not yet been well described. The potential risks of generating triclosan-resistant pathogenic microorganisms or of the selection of resistant strains are some areas of concern. The aim of the present study was to (1) obtain information on baseline levels of triclosan in plasma and urine, and (2) study the pharmacokinetic pattern of triclosan after a single-dose intake. Ten healthy volunteers were exposed to a single oral dose of 4 mg triclosan by swallowing an oral mouthwash solution. Triclosan in plasma and urine was followed before and up to 8 d after exposure. Triclosan levels in plasma increased rapidly, with a maximum concentration within 1 to 3 h, and the terminal plasma half-life was 21 h. The major fraction was excreted within the first 24 h. The accumulated urinary excretion varied between the subjects, with 24 to 83% of the oral dose being excreted during the first 4 d after exposure. In conclusion, triclosan appears to be readily absorbed from the gastrointestinal tract and has a rapid turnover in humans. The high lipid solubility of the substance gives rise to questions regarding distribution properties and accumulation. The findings of the present study form a basis for greater understanding of the toxicokinetic properties of triclosan in humans.

The staffs at the Laboratory of Pharmacology of Huddinge University Hospital and at the Institute of Applied Environmental Research, University of Stockholm, are gratefully acknowledged for excellent assistance. This study was supported by the Swedish Environmental Protection Agency, the Swedish Research Council for Environment, Agricultural Sciences, and Spatial Planning (number 2002-0706), and the Swedish Patent Revenue Fund for Research in Preventive Dentistry.

Notes

Remberger, M., Sternbeck, J., and Strömberg, K. 2002. Screening av triclosan och vissa bromerade fenoliska ämnen i Sverige [Screening of triclosan and some brominated, phenolic compounds in Sweden] IVL‐rapport B1477–2.