Antinociceptive potencies of 6-amino acid conjugates of 14-O-methyloxymorphone against radiant heat-induced nociception in the tail-flick test in the rat after s.c. administration as a function of time Numbers in parentheses are 95% confidence limits. n = 5 to 8.
| Compound | ED50 (nmol/kg s.c.) | |||
|---|---|---|---|---|
| Time after s.c. Administration (min) | ||||
| 30 | 60 | 120 | 180 | |
| Morphine | 6053b (4037–9080) | 7626 (5084–11,439) | 13,285 (8856–19,929) | —a |
| Fentanyl | 38.6b (25.0–60.0) | 62.4 (40.1–96.9) | 395 (247–632) | — |
| 14-O-Methyloxymorphone | 14.9b (9.6–23.0) | 24.0 (14.6–39.6) | 60.6 (35.6–103) | — |
| HS-730 | 137 (85.7–219) | 58.5b (36.5–93.7) | 143 (86.8–237) | 437 (243–786) |
| HS-731 | 50.8 (32.7–78.7) | 29.0b (18.8–44.9) | 43.3 (27.9–67.1) | — |
| HS-935 | 150 (99.8–225) | 68.9b (45.9–103) | 104 (69.1–156) | — |
| HS-936 | >850 | 53.4b (31.4–90.8) | 165 (107–256) | 376 (203–695) |
| HS-937 | 641 (428–962) | 315b (191–520) | 340b (200–577) | 688 (382–1238) |
| HS-938 | >3600 | >3600 | >3600 | — |