ABSTRACT
Inhalation is, in many senses, a special case route of administration for toxicology as a whole and for acute toxicology in particular. As will be reviewed here, animal inhalation studies are difficult and complex to perform correctly. Generally, only two broad types of acute studies are performed using this route (the acute systemic exposure and the pul monary sensitization/irritation study), and, typically, such acute toxi cology studies are not performed well. The complexity and cost of such studies firmly dictates that they be performed only when there are sub stantial opportunities for human inhalation exposure. Such opportunities occur under three broad categories. In order of decreasing occurrence or importance, these are occupational (from the work place, either in the normal course of operations or during maintenance or accident situ ations), environmental (a spectacular example being Bhophal), or when the material is to be used as a therapeutic by this route.
