Arsenal have already shifted a number of players out of their squad in this window.
As well as Kolasinac, William Saliba has also left on loan to play for French side Nice.
Meanwhile, Mesut Ozil and Sokratis Papastathopoulos have both had their contracts cancelled.
Arteta says he has trimmed the squad as much as he wanted and is now focused on bringing in targets if he can.
“We are in that process right now,” he added.