ABSTRACT
Laboratory animals such as rats, guinea pigs, dogs, and monkeys are commonly used in inhalation toxicology research as surrogates for human exposures. The toxicity of a substance inhaled by these animals depends partially on the extent and loci of deposition in the respiratory tracts. Deposition, in turn, depends on particle characteristics (size, density, and shape), on physical characteristics of the respiratory system, and on the kinetics of gas flow within the system. Differences in deposition characteristics between humans and experimental animals will influence extrapolation of toxicity results obtained with these animals to human beings.
