Wiktionary
busulfan
n. A particular drug used in chemotherapy.
Wikipedia
Busulfan
Busulfan (Myleran, GlaxoSmithKline, Busulfex IV, Otsuka America Pharmaceutical, Inc.) is a cancer drug, in use since 1959.
Busulfan is a cell cycle non-specific alkylating antineoplastic agent, in the class of alkyl sulfonates. Its chemical designation is 1,4-butanediol dimethanesulfonate.