ABSTRACT
The maximum tolerated dose, as it applies to particle toxicology, is a concept that takes the possibility of overload-related pathology into account and seeks to carry out the exposure at a level that cause overload. The best studied particles in terms of the adverse health effects are those that are encountered in the occupational setting. In Chronic obstructive pulmonary disease the deposition of ultrafines has been reported to be more efficient due probably to changes in the characteristics of air flow within the lungs. Ultrafine particles are particles less than 100 nm in diameter, such as ultrafine carbon black, ultrafine TO2 and ultrafine metals that are produced industrially. The maximum tolerated dose is an important concept in this regard. ‘Classical overload’ occurs in rats exposed to high levels of airborne particles which accumulate in the lungs to a point where there is failure of clearance, increased build-up of dose, inflammation, proliferation, fibrosis and tumour production.
