Item for Ryze (battlemages)

An item that gives ability power based lifesteal, and I do know of but unfortunately this item is only useful for byhrid damage champs. Giving mages a lifesteal item would be fair, naturally because of the high damage mages can deal the item's lifesteal would be nowhere near or other ad items. But giving champs like Ryze a bit more survivability would have it's ups (and downs, no one likes seeing veigar go from 1 health to full pool)