Pharmacology for Anaesthesia and Intensive Care

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6 Mathematics and pharmacokinetics

Vd

k

C

(a) One-compartment model

k 10

V 1 V^2

k 12

k 21

(b) Two-compartment model

(c) Three-compartment model

C

k 10

V 1 V^2

k 12

k 21

C

k 13

V 3 k 31

Figure 6.9.Compartmental models.(a) One-compartment model, volume of distribution

Vd, rate constant for elimination k. (b) Two-compartment model, central compartment has

volume V 1 and peripheral compartment has volume V 2 .Rateconstants for transfer

between compartments are described in the text. The rate constant for elimination is k 10.

(c) Three-compartment model. This is similar to the two-compartment model but with the

addition of a second peripheral compartment, volume V 3 ,with slower kinetics.