The synthesis of labelled forms of saquinavir

The development of the HIV-protease inhibitor, saquinavir (Ro 31-8959), required a range of analytical methods for the measurement of the parent drug and drug-related material in biological fluids. This paper describes the synthesis of 14-carbon and tritium labelled compounds used for in vivo and in vitro investigations of the absorption and disposition of saquinavir in animals and man. It also discusses the preparation of saquinavir labelled with deuterium and stable isotopes of carbon and nitrogen. These forms of the drug were needed for bioequivalence studies in which HPLC/MS/MS was employed for the measurement of plasma concentrations. Finally, the synthesis of a 125-iodine labelled tracer used in a radioimmunoassay for saquinavir is described. Copyright © 1998 John Wiley & Sons, Ltd.