Saquinavir-13C6 (Ro 31-8959-13C6) is 13C labeled Saquinavir (HY-17007). Saquinavir (Ro 31-8959) is an orally active HIV protease inhibitor that can be used in the research of AIDS. Saquinavir also has anti-inflammatory activity and can induce apoptosis of human red blood cells[1][2].