Respiratory retention of inhaled toluene and benzene in the dog.

This study deals with the inhalation of toluene and benzene found in the vapor phase of cigarette smoke. Determined in this study were the uptake of each substance by the total respiratory tract and by the upper and lower portions under varying conditions of ventilatory rate, tidal volume, and concentration inhaled. Retention by the total tract of toluene fell within the range of 91-94% at all ventilatory rates seen, indicating no relationship between rate and retention. With benzene, total tract retention varied from 88 to 68% with an inverse relationship between retention and rate apparent. This relationship was seen in all types of experiments conducted with benzene. Upper tract retention revealed an uptake of about 89% for both one- and two-way experiments with toluene. In the benzene experiments retention varied from 80 to 61% and from 81 to 63% in the one- and two-way procedures, respectively. Mean lower tract retention was 90% with toluene at all ventilatory rates considered. Benzene retention varied from 74 to 61% as the rate increased from 6 to 18 inhalations/min.