Discovery of novel 2-((pyridin-3-yloxy)methyl)piperazines as α7 nicotinic acetylcholine receptor modulators for the treatment of inflammatory disorders.

Herein we report the design, synthesis, and structure-activity relationships for a new class of α7 nicotinic acetylcholine receptor (nAChR) modulators based on the 2-((pyridin-3-yloxy)methyl)piperazine scaffold. The oxazolo[4,5-b]pyridine, (R)-18, and 4-methoxyphenylurea, (R)-47, were identified as potent and selective modulators of the α7 nAChR with favorable in vitro safety profiles and good oral bioavailability in mouse. Both compounds were shown to significantly inhibit cellular infiltration in a murine model of allergic lung inflammation. Despite the structural and in vivo functional similarities in the compounds, only (R)-18 was shown to be an agonist. Compound (R)-47 demonstrated silent agonist activity. These data support the hypothesis that the anti-inflammatory activity of the α7 nAChR is mediated by a signal transduction pathway that is independent of ion current.

Novel hydrophobically modified asymmetric RNAi compounds (sd-rxRNA) demonstrate robust efficacy in the eye.

PURPOSE: The major challenges of developing an RNAi therapeutic include efficient delivery to and entry into the cell type of interest. Conventional ("naked" and chemically stabilized) small interfering RNAs (siRNAs) have been used in the eye in the past but they demonstrated limited clinical efficacy. Here we investigated a recently developed class of small, hydrophobic, asymmetric RNAi compounds. These compounds, termed "self-delivering rxRNAs" (sd-rxRNA(®)), are extensively modified, have a small duplex region of <15 base pairs, contain a fully phosphorothioated single-stranded tail, and readily enter cells and tissues without the requirement for a delivery vehicle. METHODS: We compared sd-rxRNA compounds with stabilized siRNAs in vitro (in ARPE-19 cells) and in vivo (intravitreal injection in mouse and rabbit eyes). Specifically, we investigated the retinal uptake, distribution, efficacy, and preliminary safety of sd-rxRNAs. RESULTS: Treatment with sd-rxRNAs resulted in uniform cellular uptake and full retina penetration in both animal models while no detectable cellular uptake was observed with stabilized siRNAs either in vitro or in vivo. Further, both in vitro and in vivo delivery (without any transfection reagent or formulation) resulted in a significant reduction of the targeted mRNA levels, which lasted 14-21 days in vivo. Retinal morphology and function were unaltered following a single administration of sd-rxRNAs. CONCLUSION: These data support the potential of developing sd-rxRNAs as a therapeutic for ocular disease.

5-Lipoxygenase inhibition by N-hydroxycarbamates in dual-function compounds.

A series of N-hydroxycarbamates containing a histaminergic H(1) receptor antagonist pharmacophore was synthesized. In vitro assays determined the compounds had both histaminergic binding and 5-lipoxygenase inhibiting activities comparable to the corresponding N-hydroxyurea analog. Animal models demonstrated antihistaminergic and the 5-lipopxygenase inhibitory activity, with the N-hydroxyurea analog having a better overall profile.

5-lipoxygenase inhibitors with histamine H(1) receptor antagonist activity.

A series of novel compounds with both 5-lipoxygenase (5-LO) inhibitory and histamine H(1) receptor antagonist activity were designed for the treatment of asthma. These dual-function compounds were made by connecting 5-LO and H(1) pharmacophores,N-hydroxyureas and benzhydryl piperazines, respectively. A range of in vitro activities was observed, with the furan analog 10 demonstrating both activities in an animal model. The activities observed were compared to single-function drugs.

Cetirizine and loratadine-based antihistamines with 5-lipoxygenase inhibitory activity.

A series of compounds possessing both H(1) histamine receptor antagonist and 5-lipoxygenase (5-LO) inhibitory activities was synthesized. The H(1)-binding scaffolds of cetirizine, efletirizine, and loratadine were linked to a lipophilic N-hydroxyurea, the 5-LO inhibiting moiety of zileuton. Both activities were observed in vivo, as was increased CYP3A4 inhibition compared to their respective single-function drugs. Selected analogs in the series were shown to be orally active in guinea pig models.