Two youngsters, Joe Willock and Ainsley Maitland-Niles have completed loan deals away from Arsenal to Newcastle and West Brom respectively.
Joining the two youngsters to move elsewhere on the transfer deadline day was Shkodran Mustafi, who moved to Schalke on a permanent deal.
21-year-old Willock will spend the rest of the season with the Magpies.
Arsenal and Newcastle began talks over a temporary switch for the England Under-21 international on the final day of the January transfer window.
Meanwhile, Maitland-Niles, 23, has made the move to the Hawthorns until the end of the season as well.
Sokratis Papastathopoulos joined Olympiakos earlier this month after being released from his contract, William Saliba, Sead Kolasinac and Matt Smith have left on loan, while Matt Macey joined Hibernian on a permanent basis.