Distribution and Pharmacokinetics Models - Pesticide Biotransformation and Disposition - page 139

Inhaled dose

Exhaled

Alveolar space

Lung blood

Kidney

Excreted

Poorly perfused tissues

Fat

Dermal
dose

Rapidly perfused tissues

Skin

Oral
dose

Liver

Metabolized

Figure 6.11 Schematic representation of a physiologically based pharmacokinetic model. This model
contains descriptions of exposure by the inhalation, oral, and dermal routes and elimination by exha-
lation, excretion, and metabolism.

Table 6.3 Some Existing PBPK Models for Pesticides from Various Chemical Classes
Pesticide References

Dieldrin Leung and Paustenbach (1988)

Kepone (chlordecone) el-Masri et al. (1995, 1996) ; Yang et al. (1995a,b)

Lindane (hexachlorocyclohexane) DeJongh and Blaauboer (1997)

Hexachlorobenzene Freeman et al. (1989); Roth et al. (1993)

Diisopropylfluorophosphate Gearhart et al. (1994)

Dichlorobenzene Hissink et al. (1997)

2,4-Dichlorophenoxyacetic acid Kim et al. (1994, 1995, 1996)

Captan Fisher et al. (1992); Woollen (1993)

Chlorpyrifos Timchalk et al. (2002)

the compartments in which these processes occur. PBPK models require three types
of parameters as inputs: physiological, physicochemical, and biochemical. Physiological
parameters (e.g., pulmonary ventilation rate, cardiac output, blood flow to tissues, and
tissue volumes) for humans and several laboratory animal species are available in the
literature ( Arms and Travis, 1988 ). Physiological parameters, which are not dependent
on the chemical under study, are assumed to be constant for a given species. However,
if it is known that physiological parameters change with time or a particular exposure
scenario, those changes can be easily incorporated into PBPK models. Physicochemical