. 2019 Jun 13;10(7):1187–1191. doi: 10.1039/c9md00222g

Table 1. Affinities of fentanyl derivatives for the σ₁R and μOR19.

No	Compound	Structural variation (cf.Chart 1)							Affinity for
		N-Sub	R_β	R₃	R_4-ax	R_para	R_ω-1	R_ω	σ₁R	μOR from ref. 19
		N-Sub	R_β	R₃	R_4-ax	R_para	R_ω-1	R_ω	IC₅₀ ± S.D. ^a	IC₅₀ ± S.D. ^b
1	Fentanyl	PhEth ^c	H	H	H	H	H	H	4973 ± 2.3	1.23 ± 0.14
2	Benzylfentanyl	Benz ^d	n/a ^e	H	H	H	H	H	322.1 ± 1.9	489.7 ± 28.6
3	Thenylfentanyl	ThMet ^f	n/a ^e	H	H	H	H	H	1185 ± 2.0	245.5 ± 12.9
4	β-Hydroxyfentanyl ^g	PhEth	OH	H	H	H	H	H	>10 000 ^h	2.81 ± 0.13
5	ω-Hydroxyfentanyl	PhEth	H	H	H	H	H	OH	>10 000 ^h	97.7 ± 5.8
6	ω-1-Hydroxyfentanyl ^g	PhEth	H	H	H	H	OH	H	>10 000 ^h	489.0 ± 40.6
7	p-Fluorofentanyl	PhEth	H	H	H	F	H	H	495.3 ± 2.0	0.48 ± 0.03
8	3-Methylthiofentanyl ^g	ThEth ⁱ	H	Me	H	H	H	H	465.0 ± 1.2	1.10 ± 0.10
9	Sufentanil	ThEth	H	H	CH₂OMe	H	H	H	2077 ± 2.1	0.40 ± 0.03
10	Norcarfentanil	H	n/a ^e	H	C(O)OMe	H	H	H	>10 000 ^h	295.1 ± 1.3
11	Remifentanil	C₂H₄C(O)OMe	n/a ^e	H	C(O)OMe	H	H	H	>10 000 ^h	0.60 ± 0.08
12	Alfentanil	TetrEth ^j	H	H	CH₂OMe	H	H	H	>10 000 ^h	38.9 ± 2.8
13	SKF10047 (reference)	n/a ^e	n/a ^e	n/a ^e	n/a ^e	n/a ^e	n/a ^e	n/a ^e	69.4 ± 2.1	n/d ^k

^aHalf maximal inhibitory concentration in nM (± standard deviation) of [³H]-(+)-pentazocine specific binding; the results given are means from at least three experiments performed in duplicate; values recalculated to K_i are given in Table ESI-BIND-1.

^bHalf maximal inhibitory concentration in nM ± standard deviation, taken from ref. 19.

^c2-Phenyleth-1-yl.

^dBenzyl.

^eNot applicable.

^f2-Thienylmethyl.

^gTested as an enantiomeric or diastereoisomeric (8) mixture.

^hThe values of [³H]-(+)-pentazocine displacement at 10 μM are given in Table ESI-BIND-1.

ⁱ2-Thien-2-ylethyl.

^j2-(4-Ethyl-5-oxo-4,5-dihydro-1H-1,2,3,4-tetrazol-1-yl)ethyl.

^kn/d – not determined.

Table 1. Affinities of fentanyl derivatives for the σ1R and μOR19.

Table 1. Affinities of fentanyl derivatives for the σ₁R and μOR19.