Jeptoo was suspended for four years in 2014 for a previous doping violation. The runner, who has won the Boston Marathon and the Chicago Marathon, returned to competition three years ago.
She is now suspended again after a test showed the presence of anabolic steroids.
Mukhobe is temporarily suspended for missing three doping tests since August last year, and is not allowed to compete until his case has been processed.
Among the athletes are also football and basketball players who have been temporarily suspended for various doping offenses.
