Inhalation testing of toiletries in animals

Synopsis The purpose of testing is to establish the safety of ingredients to be handled in the factory and of the products to be used by the consumer. Inhalation tests tend to require much time and are expensive; the number of inhalation tests may be reduced by preliminary measurement of the respirable fraction of an aerosol or powder, by toxicity tests on macrophages in culture, and by instillation of suspensions into the lung via the trachea. Inhalation exposures may be in whole body exposure chambers or the head only may be exposed; the techniques are discussed. The criteria of a satisfactory inhalation test are considered and histological features which should be investigated are reviewed.