Trilostane -d 3 is the deuterium-labeled Trilostane. Trilostane -d 3 (Win 24540) is a competitive and orally active 3-β-hydroxysteroiddehydrogenase ( 3β-HSD ) inhibitor. Trilostane -d 3 is a synthetic nonhormonal steroid. Trilostane -d 3 can be used for the research of breast cancer and prostate cancer.