fig2

Figure 2. Percentage difference between the measured and predicted permeation coefficients based on ten unmodified QSPR equations. These equations include 1. Fujiwara et al. (2003)^[18]; 2. Mitragotri (2002)^[22]; 3. Moody and MacPherson (2003)^[19]; 4. Moss and Cronin (2002)^[2]; 5. Potts and Guy (1992)^[23]; 6. Geinoz et al. (2004)^[1]; 7. ten Berge (2009)^[20]; 8. USEPA (2004)^[24]; 9. Vecchia and Bunge (2002)^[25]; and 10. Cleek and Bunge (1993)^[21]. QSPR: Quantitative structure-permeation relationship.