Absorption Rate Constant, ka

Figure 17.4.1 Linear Plot of Cp versus Time with ka = 3, 0.6, or 0.125 hr^-1

Before going on to calculate the parameters ka, kel, and F from data provided we can look at the effect different values of F and ka have on the plasma concentration versus time curve.

tpeak = 1, 2.75, 6.25 hour.

Notice that with higher values of ka the peak plasma concentrations are higher and earlier.

Extent of Absorption or Bioavailability, F

Figure 17.4.2 Linear Plot of Cp versus Time with F = 1, 0.66, or 0.33

Changing F values is equivalent to changing the dose. Thus the higher the F value the higher the concentration values at each time point. Since the values of kel and ka are unchanged the time of peak plasma concentration is unchanged.

Thus, tpeak = 1, 1, and 1 hour. The same in each case.

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Copyright 2001-3 David W. A. Bourne (david@boomer.org)