K

Figure 1.11 Zero-order input and one-compartment disposition box diagram.

equation (Eq. 1.22) describes an I0D1 model, and its integrated form is shown in Eqs. (1.23) and (1.24):

where k0 is the zero-order input rate constant (units of amount per time), K is the first-order elimination rate constant (units of 1/time), Vd is the volume of distribution, and Cp is the drug plasma concentration.

Figure 1.12 shows the concentration profile plotted on Cartesian coordinates and semilog scales respectively. When a zero-order input has been left on for an amount of time equal to 3.3 to 5 half-lives, Cp is considered to be at steady state (90 and 96 percent of true steady state, respectively) and is designated as Cp,ss. There is only one volume term, Vd, because the disposition is only one compartment.

First-order input and one-compartment disposition (I1D1). In this model, the input is first order, and the disposition is one compartment. The o

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