By our definition, research is the earliest stage of development that RDI covers. It is the very early stage of the program where bench analysis is taking place. This includes in vitro work, target exploration, receptor binding studies, etc. Research is considered active development. It is the stage prior to preclinical work which is the next stage of development where molecules are tested in animals.
Conversely, inactive development includes suspended, discontinued or no development reported. Although, with 'no development reported' there may be development going on however, no progress has been reported for a substantial period.