Points to be considered for conducting toxicokinetic studies under GLP and for validating analytical methods

Issues discussed by TK Working Group of the JPMA for the implementation of ICH guideline for toxicokinetics (TK) are summarized. 1) A unique management system may be needed for toxicokinetic studies, when TK measurements are conducted in a center for pharmacokinetics and metabolism studies, i.e. in a separate location or by an independent organization from those for toxicity studies. 2) TK measurement should be conducted in compliance with the protocols and validated SOPs for analytical methods. 3) Every time when study conditions in toxicity studies and/or TK measurement are changed, the analytical method should be more or less revalidated. The present paper will discuss some practical issues to be involved in such situations, and possible countermeasures for them.