The present technology relates to depots for the treatment of postoperative pain via sustained, controlled release of a therapeutic agent. In some embodiments, the depot may comprise a therapeutic region comprising an analgesic, and a control region comprising a bioresorbable polymer and a releasing agent mixed with the polymer. The releasing agent may be configured to dissolve when the depot is placed in vivo to form diffusion openings in the control region. The depot may be configured to be implanted at a treatment site in vivo and, while implanted, release the therapeutic agent at the treatment site for no less than 3 days.