Akikan! OVA

The story revolves around a typical high school boy named Kakeru Daichi and the can of melon juice soda that he bought from a vending machine. The can suddenly transforms into a beautiful but standoffish girl that Kakeru nicknames 'Melon', and more 'Akikan' ('empty can') girls appear. However, Akikan girls need to be infused with carbon dioxide in order to turn into a human.(Source: ANN, edited)