Dopamine/Serotonin Receptor Ligands. 12: SAR Studies on Hexahydro-dibenz[<i>d</i>,<i>g</i>]azecines Lead to 4-Chloro-7-methyl-5,6,7,8,9,14-hexahydrodibenz[<i>d,g</i>]azecin-3-ol, the First Picomolar D₅-Selective Dopamine-Receptor Antagonist

Hydroxylated, methoxylated, and/or chlorinated 7-methyl-5,6,7,8,9,14-hexahydrodibenz[d,g]azecines were generally synthesized out of substituted 2-phenylethylamines and isochromanones by Bischler−Napieralski cyclization of the resulting benzamides to dibenzoquinolizines and the quaternization and cleavage of the central C−N bond under Birch conditions. Chlorination of 2-phenylethylamines was useful for the site direction of cyclization, but chlorine atoms were removed under Birch conditions so that chlorination had to be repeated to get the respective chlorinated dibenz[d,g]azecines. The target compounds were tested for their affinity at the different human-cloned dopamine-receptor subtypes (D1 family, D2 family). Generally, hydroxylation and chlorination of the dibenz-azecines increased affinities significantly. 1-Chloro-2-hydroxy-hexahydro-dibenz[d,g]azecine was a subnanomolar antagonist at both subtype families. 4-Chloro-3-hydroxy-7-methyl-5,6,7,8,9,14-hexahydro-dibenz[d,g]azecine was identified as the most potent and selective dopamine D5 receptor ligand described to date with Ki(D1) = 0.83, Ki(D2L) = 4.0, Ki(D3) = 24.6, Ki(D4) = 5.2 nM, and Ki(D5) = 57 pM (radioligand binding experiments), respectively

Dopamine/Serotonin Receptor Ligands. 12: SAR Studies on Hexahydro-dibenz[<i>d</i>,<i>g</i>]azecines Lead to 4-Chloro-7-methyl-5,6,7,8,9,14-hexahydrodibenz[<i>d,g</i>]azecin-3-ol, the First Picomolar D₅-Selective Dopamine-Receptor Antagonist

Hydroxylated, methoxylated, and/or chlorinated 7-methyl-5,6,7,8,9,14-hexahydrodibenz[d,g]azecines were generally synthesized out of substituted 2-phenylethylamines and isochromanones by Bischler−Napieralski cyclization of the resulting benzamides to dibenzoquinolizines and the quaternization and cleavage of the central C−N bond under Birch conditions. Chlorination of 2-phenylethylamines was useful for the site direction of cyclization, but chlorine atoms were removed under Birch conditions so that chlorination had to be repeated to get the respective chlorinated dibenz[d,g]azecines. The target compounds were tested for their affinity at the different human-cloned dopamine-receptor subtypes (D1 family, D2 family). Generally, hydroxylation and chlorination of the dibenz-azecines increased affinities significantly. 1-Chloro-2-hydroxy-hexahydro-dibenz[d,g]azecine was a subnanomolar antagonist at both subtype families. 4-Chloro-3-hydroxy-7-methyl-5,6,7,8,9,14-hexahydro-dibenz[d,g]azecine was identified as the most potent and selective dopamine D5 receptor ligand described to date with Ki(D1) = 0.83, Ki(D2L) = 4.0, Ki(D3) = 24.6, Ki(D4) = 5.2 nM, and Ki(D5) = 57 pM (radioligand binding experiments), respectively

Data_Sheet_1_S-Ketamine Oral Thin Film—Part 1: Population Pharmacokinetics of S-Ketamine, S-Norketamine and S-Hydroxynorketamine.PDF

Ketamine is administered predominantly via the intravenous route for the various indications, including anesthesia, pain relief and treatment of depression. Here we report on the pharmacokinetics of sublingual and buccal fast-dissolving oral-thin-films that contain 50 mg of S-ketamine in a population of healthy male and female volunteers. Twenty volunteers received one or two oral thin films on separate occasions in a randomized crossover design. The oral thin films were placed sublingually (n = 15) or buccally (n = 5) and left to dissolve for 10 min in the mouth during which the subjects were not allowed to swallow. For 6 subsequent hours, pharmacokinetic blood samples were obtained after which 20 mg S-ketamine was infused intravenously and blood sampling continued for another 2-hours. A population pharmacokinetic analysis was performed in NONMEM pharmacokinetic model of S-ketamine and its metabolites S-norketamine and S-hydroxynorketamine; p < 0.01 were considered significant. S-ketamine bioavailability was 26 ± 1% (estimate ± standard error of the estimate) with a 20% lower bioavailability of the 100 mg oral thin film relative to the 50 mg film, although this difference did not reach the level of significance. Due to the large first pass-effect, 80% of S-ketamine was metabolized into S-norketamine leading to high plasma levels of S-norketamine following the oral thin film application with 56% of S-ketamine finally metabolized into S-hydroxynorketamine. No differences in pharmacokinetics were observed for the sublingual and buccal administration routes. The S-ketamine oral thin film is a safe and practical alternative to intravenous S-ketamine administration that results in relatively high plasma levels of S-ketamine and its two metabolites.</p

Dopamine/Serotonin Receptor Ligands. 10: SAR Studies on Azecine-type Dopamine Receptor Ligands by Functional Screening at Human Cloned D₁, D_2L, and D₅ Receptors with a Microplate Reader Based Calcium Assay Lead to a Novel Potent D₁/D₅ Selective Antagonist

On the basis of the benz[d]indolo[2,3-g]azecine derivative 1 (LE300), structure−activity relations were investigated in order to identify the pharmacophore in this new class of ligands. Various structural modifications were performed and the inhibitory activities at human cloned D1, D2L, and D5 receptors were measured by using a simple fluorescence microplate reader based calcium assay. Subsequently, the affinities of active compounds were estimated by radioligand binding experiments. Deleting one of the aromatic rings as well as replacing it by a phenyl moiety abolishes the inhibitory activities almost completely. Contraction of the 10-membered central ring decreases them significantly. The replacement of indole by thiophene or N-methylpyrrole reduces the inhibitory activity, whereas replacing the indole by benzene increases it. Finally, the hydroxylated dibenz[d,g]azecine derivative 11d (LE404) was found to be more active than the lead 1 in the functional calcium assay as well as in radioligand displacement experiments