Relationship between blood/air partition coefficients of lipophilic organic solvents and blood triglyceride levels.

The blood/air partition coefficient is one of the important parameters for understanding the pharmacokinetics of organic solvents. In conventional pharmacokinetic models, the partition coefficient has been used as a constant value for each solvent. However, blood triglyceride content varies according to a diet, and the variation may affect the partition coefficient of lipophilic organic solvents. In this study, the relationship between the blood/air partition coefficient of lipophilic organic solvents and plasma triglyceride concentrations was clarified. Corn oil (4.0 ml/kg) was administered orally to male Wistar rats, and blood samples were collected 3 h after the administration, when the plasma triglyceride level reached a peak. Control rats received the same amount of distilled water via the same route. The blood/air partition coefficients of five types of lipophilic solvents (m-xylene, trichloroethylene, 1,1,1-trichloroethane, chloroform and carbon tetrachloride) were determined in these two groups of blood samples. The hematological and biochemical parameters were also examined in the same blood samples. Although the mean plasma triglyceride level in the oil group increased about 3.3 times compared with that in the control group, the increase in the blood/air partition coefficients of the five lipophilic solvents was relatively low (approximately 1.2-1.5 times). We concluded that the diet has no significant effect on the blood/air partition coefficients of organic solvents, and the value can be used as a constant parameter for each solvent in a physiological simulation model.