Theoretical study of haemoperfusion: drugs obeying a one-compartment pharmacokinetics model.

A general theory of haemoperfusion for drugs obeying the one-compartment pharmacokinetics model is proposed. The following theoretical cases are investigated: First case Adsorption and desorption are first-order reactions without biotransformation, and elimination rate is first-order. Two particular cases are examined: no desorption and alpha = beta. Second case: Adsorption and desorption rates are first-order, without biotransformation, and elimination rate is zero-order. Third case: Adsorption rate is first-order and desorption rate is zero-order, without biotransformation, and elimination is either first-order or zero-order. Fourth case Adsorption rate is zero-order and desorption rate is first-order, without biotransformation, and elimination is either first-order or zero-order. Fifth case: Adsorption and desorption rates are first-order, with biotransformation. In all these pharmacokinetics models for haemoperfusion, theoretical computations lead to the values of adsorbed amount and plasma level, in relation to time. Clearances are also computed. In most cases, haemoperfusion must be performed quickly because of the desorption phenomenon. Parameters modulating the adsorption process are: surface area, blood flow, drug concentration in blood, adsorbent nature and adsorbent quantity.