Aim: To assess the effects on general activity and behaviour of the test item after single dose administration in rodents. 

Background information: The assessment of potential undesirable pharmacodynamic effects on the central nervous system is a regulatory requirement for the development of new therapeutic agents (ICH S7A). As such, these studies must be conducted under GLP-compliance and generally in advance of first in human administration (ICH M3(R1)). To this respect, the modified Irwin’s test allows to assess effects on motor activity, behavioral changes, coordination, sensory/motor reflex responses and body temperature.

Further to this, the preliminary assessment (under non-GLP conditions), during the candidate selection phase, of potential undesirable effects on the central nervous system can help to de-risk the selection process and increase the chance for success.

In this modified Irwin’s test, animals are administered different single dose levels of the test item to identify potential therapeutic uses and in the selection of appropriate doses for subsequent assays.