Biological Monitoring of Exposure to Organic Solvent Vapors II. Simulation Studies using a Physiological Pharmacokinetic Model for m-Xylene

Takashi KANEKO, Kazushi ENDOH, Akio SATO
1991
The relationship between external and internal doses of m-xylene afid the effects of body weight, body fatcontent, sex, and phys'ical activity on the pharmacokinetics of m-xylene were studied using a physiological simulation model. 1. Adow exposure concentrations, equal time-weighted average (TWA) concentrations gave almost the same intemal dose of m-xylene. 2. The m-xylene concentration in the blood increased continuously with increasing m-xylene concentration in inhaled air. By contrast, the
more » ... xcretion rate of m-methyl hippuric acid (m-MHA) in the urine approached a plateau with increasing m-xylene exposure concentration. 3. The larger the body size, the larger the amount of m-xylene absorbed, However, no significant change was found in m-xylene concentration in the blood with increase in body size. By contrast, the amounts of m-MHA excreted in the urine varied with body size: the Iarger the body size, the greater was the rate of urinary m-MHA excretion. 4. Both m-xylene concentration in the blood and the rate of urinary m-MHA excretion were higher ln a slim than in an obese man dttring exposure, but this relationship was reversed in due course of time after exposure. 5. The physical activity (50 W) during exposure greatly increased the blood concentration of m-xylene as well as the rate of urinary m-MHA excretion. 6. The concentration of m-xylene in the blood during exposure was lower in women than in men, while the opposite was true starting about 1O hours after the end ofexposure. The rate of m-MHA excretion in the urine was lower in women than in men both during and after exposure.
doi:10.34429/00003152 fatcat:k3dgwtoydrcsza62aqj5fozbzm