Timea 15 30 45 60 75 90 105 120   b2b r2c b2 r2 b2 r2 b2 r2 b2 r2 b2 r2 b2 r2 b2 r2 Silicad 6.31 0.95 10.2 0.94 16.7 0.95 26.9 0.93 38.4 0.95 43.3 0.96 41.1 0.97 35.7 0.97 HSe 1.75 0.59 3.92 0.99 6.89 0.99 12.1 1.00 17.2 0.98 22.1 0.99 23.5 0.99 22.6 0.99 Ratiof 3.60   2.61   2.43   2.23   2.23   1.96   1.75   1.58   aTime after administration (min). bβ2 (×10−8) is the slope of the regression line for β1 in Table 2 and particle size (the number average particle diameter). cSquare of the correlation coefficient of the regression line for β1 in Table 2 and particle size. dGroup of four silica samples. eGroup of heat-treated four silica samples (HS). fβ2 of silic /β2 of HS.

Table 3: Slope (β2) and r2 of the regression lines for β1 in Table 2 and particle size.