Derivation of pharmacokinetics equations for quantitative evaluation of bioartificial liver functions

A bioartificial liver (BAL) is an extracorporeal medical device incorporating living hepatocytes in a cartridge. A variety of BALs have been developed and new devices are being introduced. Some of them have been clinically applied and from the results obtained they are claimed to be useful devices for assisting the liver functions of patients. However, there is still uncertainty as to their efficacy and their limitations are not clear. It is important to establish methods to quantitatively evaluate the metabolic and synthetic functions of BAL. In this paper, we derive simple equations for the quantitative evaluation of BAL functions on the basis of pharmacokinetics. Pharmacokinetics was originally developed to understand the processes of absorption, distribution, and elimination of administered drugs. Metabolic functions of the natural liver have been analyzed using pharmacokinetics and values of the useful parameters, clearance (CL) and intrinsic clearance (CLint), have been reported. The metabolic functions of the BAL expressed using values of CL and CLint are easily compared with those of the normal human liver. We believe that our method provides a useful basis for estimating the clinical effectiveness of BAL.