Usain Bolt, who is more than half a second off his world-record time, looks likely to be absent, even though he is expected to test his fitness at the Anniversary Games in London on July 24.
It leaves the way clear in Beijing for Justin Gatlin, Tyson Gay and Asafa Powell, all of whom have served drugs bans.
Ben Johnson wins World Championships in Seoul 1998
The race bears comparison with the notorious 1988 final in Seoul, won by Canadian Ben Johnson, who tested positive for stanozolol after the race. Five more finalists, including Britain’s Linford Christie, were tainted by drugs.
Carl Lewis, who finished second, failed a drugs test in the lead-up to the final but did not serve a ban and was cleared to run by the US Olympic Committee.