Table 1.

In Vitro Opioid Activity Profiles of Fentanyl Analogues^a

	GPI	MVD	Receptor binding			Ki ratio
Cpd	IC50 (nM)	IC50 (nM)	Kiμ (nM)	Kiδ (nM)	Kiκ (nM)	μ/δ/κ
1	22.4 ± 3.7	114 ± 9	0.448 ± 0.079	43.5 ± 4.1	0.536 ± 0.043	1/97/1.2
8a	521 ± 67	5820 ± 1040	300 ± 8	4110 ± 80	238 ± 41	1/14/0.8
8b	590 ± 85	4750 ± 790	224 ± 13	7800 ± 280	162 ± 8	1/35/0.7
10	647 ± 77	610 ± 78	96.0 ± 5.9	6820 ± 670	1850 ± 160	1/71/19
Fentanyl	3.45 ± 0.45b	9.45 ± 4.05b	5.9 ± 1.4c	568 ± 159c	298 ± 40c	1/96/51
LENK	246 ± 39	11.4 ± 1.1	9.43 ± 2.07	2.53 ± 0.35	4570 ± 550	1/0.3/485

^aValues represent means of 3–6 determinations ± SEM.

^bref.¹⁴.

^cref.¹⁵