. 2020 Mar 27;10:5653. doi: 10.1038/s41598-020-62530-w

Table 4.

Antinociceptive Potencies of N-Methylmorphinans 1–4 and Their N-Phenethyl Analogues 1a–4a in the Tail-Flick Test in Mice.

Compound	ED₅₀ (mg/kg, s.c.) (95% CL)^a
Morphine (1)	3.06 (1.76–5.31)^b
1a	0.11 (0.027–0.40)^b
Oxymorphone (2)	0.35 (0.16–0.77)^b
2a	0.15 (0.058–0.40)^b
14-OMO (3)	0.014 (0.0051–0.037)
3a	0.014 (0.0086–0.023)
14-MM (4)	0.024 (0.0093–0.062)
4a	0.024 (0.0091–0.062)

^aED₅₀ values and 95% confidence intervals (CL in parentheses) were calculated at 30 min (peak effect) from dose-response curves (n = 5–6 mice per group). ^bData from ref. ¹³.