Complex sentence: ABT-089 is a drug which acts as a subtype-selective neural nicotinic acetylcholine receptor partial agonist, binding primarily to the α4β2 subtype.
Split into simpler sentences: ABT-089 is a drug which acts as a partial agonist at neural nicotinic acetylcholine receptors. It is subtype-selective, binding primarily to the α4β2 subtype.