Who can be the target of an infused extract?

Question

The description of the discovery Infusion for the Pathfinder Alchemist class reads:

"When the alchemist creates an extract, he can infuse it with an extra bit of his own magical power. The extract created now persists even after the alchemist sets it down. As long as the extract exists, it continues to occupy one of the alchemist's daily extract slots. An infused extract can be imbibed by a non-alchemist to gain its effects."

Does that mean that when drinking an extract of a spell, that spell is cast on the person who drank it since that is the spell's effect? Or that the effect of the extract is casting the spell which means he would get to cast it choosing a target other than himself?

For example, if a character drinks an infused extract of the spell Enlarge Person, would the character drinking it enlarge in size, or would he be able to give the effect to a different character in range as if casting it?

And lastly, in the case that the effect is applied only on the character drinking the potion, if the character drinking the infused extract is the alchemist who created it, can he then choose to cast it instead of having it effect only himself? Or would it act the same way as it does with other characters drinking it?

Answer 1

An extract is “cast” by drinking it, as if imbibing a potion—the effects of an extract exactly duplicate the spell upon which its formula is based, save that the spell always affects only the drinking alchemist.

From the rules for the alchemist class. The infusion discovery does not alter this except that the drinker might not be an alchemist, so extracts still only affect their drinker, just like potions do. It doesn't matter if the alchemist possesses the infusion discovery nor if they are the one drinking it.