A Typical Two-Compartment Model

We propose to use as single-passage retention-time distributions the Ai Exp(fc) for the central compartment and the A2 Gam(A, p.) distribution for the peripheral compartment and we assume that all molecules are present in compartment 1 at initial time. According to (9.12), 

Instead of the gamma single-passage distribution for the peripheral compartment, Wise [298] proposed the mixed random walk in series distribution, 

We propose the retention-time distributions A Exp( ) and A2 Erl(A, v) for the first and second compartments, respectively. The peripheral compartment 2 is then constituted by the v pseudocompartments that are required to express Erl(A, v). It follows that 

The system now becomes an to = u+l compartment model and the probabilistic transfer differential equations are 

In the above equations, pi represents the probability that a molecule starting in compartment 1 is in compartment i at time t. By using t = At and p = n/A, one obtains the dimensionless system of differential equations 

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Scheme 7.4 shows a diagram of a typical two-compartment model. Diagram a three-compartment model in which the third compartment can only be reached from the peripheral compartment. Diagram a three-compartment model in which the third compartment is in equilibrium with both the central and peripheral compartments. 

Results from a typical two-compartment model are shown in Figure 7.4. 

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