https://www.selleckchem.com/products/fx11.html
08 mg/kg (0.04-0.16)] para-methoxyfentanyl [0.43 mg/kg (0.23-0.77)] 3-furanylfentanyl [0.51 mg/kg (0.36-0.74)] beta-methylfentanyl [0.74 mg/kg (0.64-0.85)] para-methylfentanyl [1.92 mg/kg (1.48-2.45)] fentanyl carbamate [5.59 mg/kg (4.11-7.54)] morphine [7.82 mg/kg (5.42-11.] beta'-phenylfentanyl [19.4 mg/kg (11.0-34.4)] phenylfentanyl [55.2 mg/kg (33.5-93.]. Naltrexone (1 mg/kg) increased ED50 values several fold with decreasing magnitudes of para-methylfentanyl (63.1×) para-methoxyfentanyl