An in situ pig liver esterase assay as a useful predictive tool for the likely in vitro anti viral activity of phosphoramidate pro-drugs.

The pig liver esterase (PLE) assay has been designed to "reproduce" in vitro the first step of the metabolism of phosphoramidate pro-drugs that generates the free amino acyl phosphoramidate intermediate which has been described as a key metabolite necessary but not sufficient for the biological activity. The method could be used as a predictive tool for the likely in vitro biological activity as well as for Structure-Activity Relationship establishment (SAR).