Novel Pyrrolidine Derivatives of Budesonide as Long Acting Inhaled Corticosteroids for the Treatment of Pulmonary Inflammatory Diseases

Inhaled corticosteroids (ICSs) represent the first line therapy for the treatment of asthma and are also extensively utilized in chronic obstructive pulmonary disease. Our goal was to develop a new ICS with a basic group, which can allow solid state feature modulation, achieving at the same time high local anti-inflammatory effect and low systemic exposure. Through a rational drug design approach, a new series of pyrrolidine derivatives of budesonide was identified. Within the series, several compounds showed nanomolar binding affinity ( K_i) with GR that mostly correlated with the effect in inducing GR nuclear translocation in CHO cells and anti-inflammatory effects in macrophagic cell lines. Binding and functional cell-based assays allowed identifying compound 17 as a potent ICS agonist with a PK profile showing an adequate lung retention and low systemic exposure in vivo. Finally, compound 17 proved to be more potent than budesonide in a rat model of acute pulmonary inflammation.

Discovery and Optimization of Thiazolidinyl and Pyrrolidinyl Derivatives as Inhaled PDE4 Inhibitors for Respiratory Diseases

Phosphodiesterase 4 (PDE4) is a key cAMP-metabolizing enzyme involved in the pathogenesis of inflammatory disease, and its pharmacological inhibition has been shown to exert therapeutic efficacy in chronic obstructive pulmonary disease (COPD). Herein, we describe a drug discovery program aiming at the identification of novel classes of potent PDE4 inhibitors suitable for pulmonary administration. Starting from a previous series of benzoic acid esters, we explored the chemical space in the solvent-exposed region of the enzyme catalytic binding pocket. Extensive structural modifications led to the discovery of a number of heterocycloalkyl esters as potent in vitro PDE4 inhibitors. (S*,S**)-18e and (S*,S**)-22e, in particular, exhibited optimal in vitro ADME and pharmacokinetics properties and dose-dependently counteracted acute lung eosinophilia in an experimental animal model. The optimal biological profile as well as the excellent solid-state properties suggest that both compounds have the potential to be effective topical agents for treating respiratory inflammatory diseases.

Discovery of a novel isoxazoline derivative of prednisolone endowed with a robust anti-inflammatory profile and suitable for topical pulmonary administration

A novel glucocorticoids series of (GCs), 6α,9α-di-Fluoro 3-substituted C-16,17-isoxazolines was designed, synthesised and their structure-activity relationship was evaluated with glucocorticoid receptor (GR) binding studies together with GR nuclear translocation cell-based assays. This strategy, coupled with in silico modelling analysis, allowed for the identification of Cpd #15, an isoxazoline showing a sub-nanomolar inhibitory potency (IC50=0.84 nM) against TNFα-evoked IL-8 release in primary human airways smooth muscle cells. In Raw264.7 mouse macrophages, Cpd #15 inhibited LPS-induced NO release with a potency (IC50=6 nM)>10-fold higher with respect to Dexamethasone. Upon intratracheal (i.t.) administration, Cpd #15, at 0.1 μmol/kg significantly inhibited and at 1 μmol/kg fully counteracted eosinophilic infiltration in a model of allergen-induced pulmonary inflammation in rats. Moreover, Cpd #15 proved to be suitable for pulmonary topical administration given its sustained lung retention (t1/2=6.5h) and high pulmonary levels (>100-fold higher than plasma levels) upon intratracheal administration in rats. In summary, Cpd #15 displays a pharmacokinetic and pharmacodynamic profile suitable for topical treatment of conditions associated with pulmonary inflammation such as asthma and COPD.

CHF6001 I: a novel highly potent and selective phosphodiesterase 4 inhibitor with robust anti-inflammatory activity and suitable for topical pulmonary administration

This study examined the pharmacologic characterization of CHF6001 [(S)-3,5-dichloro-4-(2-(3-(cyclopropylmethoxy)-4-(difluoromethoxy)phenyl)-2-(3-(cyclopropylmethoxy)-4-(methylsulfonamido)benzoyloxy)ethyl)pyridine 1-oxide], a novel phosphodiesterase (PDE)4 inhibitor designed for treating pulmonary inflammatory diseases via inhaled administration. CHF6001 was 7- and 923-fold more potent than roflumilast and cilomilast, respectively, in inhibiting PDE4 enzymatic activity (IC50 = 0.026 ± 0.006 nM). CHF6001 inhibited PDE4 isoforms A-D with equal potency, showed an elevated ratio of high-affinity rolipram binding site versus low-affinity rolipram binding site (i.e., >40) and displayed >20,000-fold selectivity versus PDE4 compared with a panel of PDEs. CHF6001 effectively inhibited (subnanomolar IC50 values) the release of tumor necrosis factor-α from human peripheral blood mononuclear cells, human acute monocytic leukemia cell line macrophages (THP-1), and rodent macrophages (RAW264.7 and NR8383). Moreover, CHF6001 potently inhibited the activation of oxidative burst in neutrophils and eosinophils, neutrophil chemotaxis, and the release of interferon-γ from CD4(+) T cells. In all these functional assays, CHF6001 was more potent than previously described PDE4 inhibitors, including roflumilast, UK-500,001 [2-(3,4-difluorophenoxy)-5-fluoro-N-((1S,4S)-4-(2-hydroxy-5-methylbenzamido)cyclohexyl)nicotinamide], and cilomilast, and it was comparable to GSK256066 [6-((3-(dimethylcarbamoyl)phenyl)sulfonyl)-4-((3-methoxyphenyl)amino)-8-methylquinoline-3-carboxamide]. When administered intratracheally to rats as a micronized dry powder, CHF6001 inhibited liposaccharide-induced pulmonary neutrophilia (ED50 = 0.205 μmol/kg) and leukocyte infiltration (ED50 = 0.188 μmol/kg) with an efficacy comparable to a high dose of budesonide (1 μmol/kg i.p.). In sum, CHF6001 has the potential to be an effective topical treatment of conditions associated with pulmonary inflammation, including asthma and chronic obstructive pulmonary disease.

Novel class of benzoic acid ester derivatives as potent PDE4 inhibitors for inhaled administration in the treatment of respiratory diseases

The first steps in the selection process of a new anti-inflammatory drug for the inhaled treatment of asthma and chronic obstructive pulmonary disease are herein described. A series of novel ester derivatives of 1-(3-(cyclopropylmethoxy)-4-(difluoromethoxy)phenyl)-2-(3,5-dichloropyridin-4-yl) ethanol have been synthesized and evaluated for inhibitory activity toward cAMP-specific phosphodiesterase-4 (PDE4). In particular, esters of variously substituted benzoic acids were extensively explored, and structural modification of the alcoholic and benzoic moieties were performed to maximize the inhibitory potency. Several compounds with high activity in cell-free and cell-based assays were obtained. Through the evaluation of opportune in vitro ADME properties, a potential candidate suitable for inhaled administration in respiratory diseases was identified and tested in an in vivo model of pulmonary inflammation, proving its efficacy.

Synthesis of glycose carbamides and evaluation of the induction of erythroid differentiation of human erythroleukemic K562 cells

A series of carbamides derived from 1,2:5,6-di-O-isopropylidene-D-gluco- and D-allofuranose as well as their 5,6-O-deprotected analogues (2 and 4) and methyl 3,4-O-isopropylidene-alpha- and beta-D-galactopyranosides (5 and 6) have been prepared in order to evaluate their ability to induce erythroid differentiation of human erythroleukemic K562 cells. Twenty out of 51 carbamides tested exhibit an appreciable activity as inducers of erythroid differentiation and have been fully characterized and described.

Structural Determinants of Torpedo californica Acetylcholinesterase Inhibition by the Novel and Orally Active Carbamate Based Anti-Alzheimer Drug Ganstigmine (CHF-2819)

Ganstigmine is an orally active, geneserine derived, carbamate-based acetylcholinesterase inhibitor developed for the treatment of Alzheimer's disease. The crystal structure of the ganstigmine conjugate with Torpedo californica acetylcholinesterase (TcAChE) has been determined at 2.40 A resolution, and a detailed structure-based analysis of the in vitro and ex vivo anti-AChE activity by ganstigmine and by new geneserine derivatives is presented. The carbamoyl moiety is covalently bound to the active-site serine, whereas the leaving group geneseroline is not retained in the catalytic pocket. The nitrogen atom of the carbamoyl moiety of ganstigmine is engaged in a key hydrogen-bonding interaction with the active site histidine (His440). This result offers an explanation for the inactivation of the catalytic triad and may account for the long duration of action of ganstigmine in vivo. The 3D structure also provides a structural framework for the design of compounds with improved binding affinity and pharmacological properties.

Synthesis and anticonvulsant activity of a class of 2-amino 3-hydroxypropanamide and 2-aminoacetamide derivatives

Several studies have demonstrated that N-substituted amino acid derivatives exhibit weak anticonvulsant activities in vivo. In the present study, a series of amides of aminoacids structurally related to aminoacetamide have been synthesised and investigated for anticonvulsant activity. Among the molecules investigated, those containing a bicyclic (tetralinyl, indanyl) group linked to the aminoacetamide chain (40, 47 and 59) were among the most active as anticonvulsants (ED50 > 10, <100 mg/kg after oral administration) against tonic seizures in the mouse maximal electroshock, bicuculline and picrotoxin tests at doses devoid of neurotoxic activity. Altogether, these results suggest the described compounds as a class of orally available anticonvulsants. The ability of these compounds to partially block veratridine-induced aspartate efflux from rat cortical synaptosomes suggests that their anticonvulsant activity may be only partly the consequence of an interaction with neuronal voltage-dependent sodium channels. Some of the most potent compounds appear worthy of a further investigation aimed at assessing their anticonvulsant activity in other models and at elucidating the underlying mechanism of action.