Fig. 2From: Intravenous patient-controlled analgesia: in vitro stability profiles of mixtures containing fentanyl, hydromorphone, oxycodone, nefopam, ondansetron, and ramosetronChanges in the concentration of drugs in B mixtures over time. The concentration measured immediately after mixture preparation was taken to be 100%. a Mixture 1B. b Mixture 2B. c Mixture 3B. d Mixture 4BBack to article page