A few years back in a game of d20 Modern, I was running a Supernatural style campaign, and my wife brought up the Charmed Ones.
Her argument was they are making Potions and then they throw them, and when the liquid LEAVES the vial, the potion has the effect. This is as opposed to having to actually swallow the liquid.
So I said 'Hmmm,' and thought about it, and my response was 'No, they are really just preparing the spell in a different format than 'Abracadabra - hand motions - crispy bad guy'.
I also brought up that some of the potions did have to br drunk, and those potions could actually be per the Brew Potion feat, but could just as well be spells prepared in a different fashion.
So, after getting a grumpy look from the missus, and being threatened again with no latenight gaming sessions, I house rules that basically they are spells stored in a device, like a scroll, and since she already had a scribe scroll ability, I simply said now instead of reading a spell, you have to throw the 'potion spell'.
A buddy of mine simply allows his players to brew the spells into a potion, but requires a ranged touch attack for the potion to have an effect.
If this issue were to come up in my Pathfinder game, I would research the brew potion cost, then the scribe scroll effect, then probably charge whichever cost more, or even just double the cost of the potion to allow a different delivery method.