Bemare Habazak - Rabbis Questions

Returning to a Gemach Newer Medicines than One Received

I used a local medicine gemach, which prefers receiving replacement medicine but also allows giving back with money. The pills they gave me were slightly past expiration. Isn’t it ribbit to give back either (new) pills or their monetary value, considering that expired medicine is worth less than normal?

Beit Din Eretz Hemda - Gazit | Shvat 7 5782