Normalized particle-count profiles in compartment

According to definitions (8.3) and (9.6), the relationship between clearance, volume of distribution, and hazard rate is again recalled  

This relationship is now considered as time-dependent because of h(t), the age-dependent hazard rate in the retention-time models, or because of V (t), the time-varying volume of distribution. For all the above models, the time-concentration curve E [C (/)] in each observed compartment is obtained by dividing E Q (/)] by V (t). For the simplest one-compartment model, two different 

In other words, the expectation of the amount behaves always as the survival function S (f) but the expectation of the concentration behaves either as the 

After bolus administration and keeping the CL constant, Weiss [245] obtained the simple time-concentration profile 

We consider now a class of models that introduce particle heterogeneity through random rate coefficients. In this conceptualization, the particles are assumed different due to variability in such characteristics as age, size, molecular conformation, or chemical composition. The hazard rates h are now considered to be random variables that vary influenced by extraneous sources of fluctuation 

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Figure 9.17 Normalized particle-count profiles in compartment 1. Dashed line and open circles for low initial conditions, and dotted line and full circles for high initial conditions.

Figure 9.18 Normalized particle-count profiles in compartment 2. Symbols as in Figure 9.17.

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