text: In this work a novel approach combining HPLC-UV on-line with oaTOF-MS and ICPMS was applied to investigate in human and rat plasma the metabolism of labelled BK (79/81 Br-Phe5) BrBK in the presence of two new dual << ACE >>/NEP inhibitors ([[ GW660511X ]] and omapatrilat) currently under clinical trial.