"Dynamic" biological exposure indexes for n-hexane and 2,5-hexanedione, suggested by a physiologically based pharmacokinetic model

Am Ind Hyg Assoc J. 1990 Jul;51(7):356-62. doi: 10.1080/15298669091369781.


Biological exposure index (BEI) of n-hexane was studied for accuracy using a physiologically based pharmacokinetic (PB-PK) model. The kinetics of n-hexane in alveolar air, blood, urine, and other tissues were simulated for different values of alveolar ventilations and also for constant and variable exposures. The kinetics of 2,5-hexanedione, the toxic n-hexane metabolite, were also simulated. The ranges of n-hexane concentrations in biological media and the urinary concentrations of 2,5-hexanedione are discussed in connection with a mean n-hexane exposure of 180 mg/m3 (50 ppm) (threshold limit value [TLV] suggested by American Conference of Governmental Industrial Hygienists [ACGIH] for 1988-89). The experimental and field data as well as those predicted by simulation with the PB-PK model were comparable. The physiological-pharmacokinetic simulations are used to propose the "dynamic" BEIs of n-hexane and 2,5-hexanedione. The use of simulation with PB-PK models enables a better understanding of the limits, advantages, and issues associated with biological monitoring of exposures to industrial solvents.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Hexanes / pharmacokinetics*
  • Hexanes / urine
  • Hexanones / pharmacokinetics*
  • Hexanones / urine
  • Humans
  • Ketones / pharmacokinetics*
  • Maximum Allowable Concentration
  • Models, Biological
  • Tissue Distribution


  • Hexanes
  • Hexanones
  • Ketones
  • n-hexane
  • 2,5-hexanedione