Intravenous patient-controlled analgesia: in vitro stability profiles of mixtures containing fentanyl, hydromorphone, oxycodone, nefopam, ondansetron, and ramosetron

Journal of Analytical Science and Technology

Table 1 Concentration, chemical formula, molecular weight, and pH of each drug used

Drug	Concentration before mixing (mg/mL)	Chemical formula	Molecular weight	pH
Fentanyl citrate	0.05	C₂₈H₃₆N₂O₈	336	5.61
Oxycodone hydrochloride	10	C₁₈H₂₂ClNO₄	315	5.05
Hydromorphone hydrochloride	2	C₁₇H₂₀ClNO₃	285	3.94
Nefopam hydrochloride	10	C₁₇H₂₀ClNO	254	5.23
Ondansetron hydrochloride	2	C₁₈H₂₀ClN₃O	294	3.14
Ramosetron hydrochloride	0.15	C₁₇H₁₇N₃O	279	4.33