Complex sentence: The main event was originally scheduled for an Interim Lightweight Championship; however, then-Lightweight Champion Sean Sherk was stripped of his UFC Lightweight Championship after the California State Athletic Commission upheld his testing positive for the anabolic steroid nandrolone.
Split into simpler sentences: The main event was originally scheduled for an Interim Lightweight Championship. However, then-Lightweight Champion Sean Sherk was stripped of his UFC Lightweight Championship after the California State Athletic Commission upheld his testing positive for the anabolic steroid nandrolone.