Direct determination of oil/saline partition coefficients

Area of Science:

• Toxicology
• Environmental Science
• Physical Chemistry

Background:

• Inhaled compound partitioning is crucial for toxicokinetic modeling.
• Oil/saline partition coefficients are often derived from separate oil/gas and saline/gas measurements.
• This method assumes no interaction between oil and saline phases.

Purpose of the Study:

• To investigate the validity of assuming no interaction between oil and saline phases when determining partition coefficients.
• To test if concurrent presence of oil and saline affects partition coefficient measurements.

Main Methods:

• Measured oil/gas and saline/gas partition coefficients for CF3(CCIF)2CF3 and 1,2-dichloroperfluorocyclobutane (C4Cl2F6).
• Determined coefficients both separately and with oil and saline phases mixed in a common container.
• Utilized olive oil and octanol as oil phases.

Main Results:

• For CF3(CCIF)2CF3, olive oil/saline partition coefficients were 13,200 (separate) and 13,300 (mixed); octanol/saline were 19,200 (separate) and 18,100 (mixed).
• For C4Cl2F6, olive oil/saline coefficients were 3660 (separate) and 3500 (mixed); octanol/saline were 5140 (separate) and 4560 (mixed).
• Differences between separate and mixed-phase determinations were small or nonexistent for both compounds.

Conclusions:

• The assumption that concurrent oil and saline presence does not affect partition coefficient measurements is supported.
• Separate determination of oil/gas and saline/gas partition coefficients is a valid method for calculating oil/saline partition coefficients.
• Findings validate current toxicokinetic modeling approaches for inhaled compounds.