Complex sentence: Marketed as Halfan, halofantrine is never used to prevent malaria and its mode of action is unknown, although a crystallographic study showed that it binds to hematin "in vitro", suggesting a possible mechanism of action.
Split into simpler sentences: Marketed as Halfan, halofantrine is never used to prevent malaria and its mode of action is unknown. A crystallographic study have shown that halofantrine binds to hematin "in vitro", suggesting a possible mechanism of action.