The rules says that an alchemist can make potions out of any spell in his formula list as long as it can be turned into a potion. So what spells can be turned into a potion and what potions can't.
Spells that are range: personal cannot be made into potions. They can however be made into infusions if you take the discovery, but that's a different case altogether!
The answer is a mix of King of Vrock and thejeff's answers.
It needs to follow the restrictions put forth in thejeff's post and also must not be a personal potion. For whatever reason, the rules are in separate places.
I have updated the d20pfsrd.com page on potions to reflect this.