Discovery of DS-3801b, a non-macrolide GPR38 agonist with N-methylanilide structure.

Motilin is a 22-amino-acid gastrointestinal (GI) hormone and is involved in the regulation of GI motility through binding to GPR38, the motilin receptor which is expressed on smooth muscle cells in the GI tract. Therefore, GPR38 agonists are expected to be novel gastrointestinal prokinetic agents for the treatment of functional gastrointestinal disorders such as gastroparesis and chronic constipation. We identified a series of N-methylanilide derivatives as novel non-macrolide GPR38 agonists. Among them, 12 di-l-tartrate (DS-3801b) was selected as a clinical candidate for further evaluation.

Formulation development and in-vitro evaluation of gastroretentive drug delivery system of loxoprofen sodium: A natural excipients based approach.

The limitations of conventional type delivery systems to retain drug (s) in the stomach has resulted in the development of novel gastroretentive drug delivery system. We developed single-layer effervescent floating tablets of loxoprofen sodium for prolong delivery in the stomach using natural polymers xanthan gum, guar gum and semisynthetic polymer HPMCK4M. All the formulations (F1-F9) were developed by varying concentrations of xanthan gum and HPMCK4M while guar gum concentration was kept constant. Two gas generating agent (s) incorporated were sodium bicarbonate and citric acid. All compendial pre and post-compression tests results were in the acceptable limits. FTIR analysis confirmed drug-polymer compatibility. The in-vitro drug release in simulated conditions i.e., 0.1 N HCl for 12 h revealed orderly increase in total floating time, i.e., less than 6 h for F1 over 12 h for F9. Formulations F1 to F4 were not capable to retard drug release up to 12 h, whereas F5-F7 for 12 h, while F8 and F9 for more than 12 h. Data fitting in various kinetic models showed that drug release best fit in first order kinetic model and F9 in zero order. Based on results data, F7 was the best among all.

Lipophilic Salts and Lipid-Based Formulations: Enhancing the Oral Delivery of Octreotide.

PURPOSE: Successful oral peptide delivery faces two major hurdles: low enzymatic stability in the gastro-intestinal lumen and poor intestinal membrane permeability. While lipid-based formulations (LBF) have the potential to overcome these barriers, effective formulation of peptides remains challenging. Lipophilic salt (LS) technology can increase the apparent lipophilicity of peptides, making them more suitable for LBF. METHODS: As a model therapeutic peptide, octreotide (OCT) was converted to the docusate LS (OCT.DoS2), and compared to the commercial acetate salt (OCT.OAc2) in oral absorption studies and related in vitro studies, including parallel artificial membrane permeability assay (PAMPA), Caco-2, in situ intestine perfusion, and simulated digestion in vitro models. The in vivo oral absorption of OCT.DoS2 and OCT.OAc2 formulated in self-emulsifying drug delivery systems (SEDDS) was studied in rats. RESULTS: LS formulation improved the solubility and loading of OCT in LBF excipients and OCT.DoS2 in combination with SEDDS showed higher OCT absorption than the acetate comparator in the in vivo studies in rats. The Caco-2 and in situ intestine perfusion models indicated no increases in permeability for OCT.DoS2. However, the in vitro digestion studies showed reduced enzymatic degradation of OCT.DoS2 when formulated in the SEDDS formulations. Further in vitro dissociation and release studies suggest that the enhanced bioavailability of OCT from SEDDS-incorporating OCT.DoS2 is likely a result of higher partitioning into and prolonged retention within lipid colloid structures. CONCLUSION: The combination of LS and LBF enhanced the in vivo oral absorption of OCT primarily via the protective effect of LBF sheltering the peptide from gastrointestinal degradation.

Improving the Gastrointestinal Stability of Linaclotide.

High susceptibility to proteolytic degradation in the gastrointestinal tract limits the therapeutic application of peptide drugs in gastrointestinal disorders. Linaclotide is an orally administered peptide drug for the treatment of irritable bowel syndrome with constipation (IBS-C) and abdominal pain. Linaclotide is however degraded in the intestinal environment within 1 h, and improvements in gastrointestinal stability might enhance its therapeutic application. We therefore designed and synthesized a series of linaclotide analogues employing a variety of strategic modifications and evaluated their gastrointestinal stability and pharmacological activity at its target receptor guanylate cyclase-C. All analogues had substantial improvements in gastrointestinal half-lives (>8 h vs linaclotide 48 min), and most remained active at low nanomolar concentrations. This work highlights strategic approaches for the development of gut-stable peptides toward the next generation of orally administered peptide drugs for the treatment of gastrointestinal disorders.

Discovery of 3-(4-(2-((1H-Indol-5-yl)amino)-5-fluoropyrimidin-4-yl)-1H-pyrazol-1-yl)propanenitrile Derivatives as Selective TYK2 Inhibitors for the Treatment of Inflammatory Bowel Disease.

TYK2 mediates signaling of IL-23, IL-12, and Type I IFN-driven responses that are critical in immune-mediated diseases. Herein, we report the design, synthesis, and structure-activity relationships (SARs) of 3-(4-(2-((1H-indol-5-yl)amino)-5-fluoropyrimidin-4-yl)-1H-pyrazol-1-yl)propanenitrile derivatives as selective TYK2 inhibitors. Among them, compound 14l exhibited acceptable TYK2 inhibition with an IC50 value of 9 nM, showed satisfactory selectivity characteristics over the other three homologous JAK kinases, and performed good functional potency in the JAK/STAT signaling pathway on lymphocyte lines and human whole blood. In liver microsomal assay studies, the clearance rate and half-life of 14l were 11.4 mL/min/g and 121.6 min, respectively. Furthermore, in a dextran sulfate sodium colitis model, 14l reduced the production of pro-inflammatory cytokines IL-6 and TNF-α and improved the inflammation symptoms of mucosal infiltration, thickening, and edema. Taken together, 14l was a selective TYK2 inhibitor and could be used to treat immune diseases deserving further investigation.

Liquid-Phase Total Synthesis of Plecanatide Aided by Diphenylphosphinyloxyl Diphenyl Ketone (DDK) Derivatives.

Plecanatide is an oral guanylate cyclase-C agonist for the treatment of gastrointestinal disorders. The large-scale supply of plecanatide is restrained primarily by its industrial manufacture. Herein we developed diphenylphosphinyloxyl diphenyl ketone (DDK) derivatives as greener supports with unique precipitation-inducing properties to aid the liquid-phase total synthesis of plecanatide without the use of chromatography. Plecanatide could be obtained in high yield, and the ultimately sheared DDK derivative residue could be directly recycled or regenerated for reuse.

Reducing Burst Release Effect of Freely Water-Soluble Drug Incorporated into Gastro-Floating Formulation Below HPMC Threshold Concentration Through Interpolymer Complex.

Undesired-burst release effect is observed in a freely water-soluble drug formulated into a gastro-floating formulation with effervescent (GFFE) delivery system. In order to address this limitation, interpolymer complex (IPC) of two swellable and non-soluble polymers, poly-ammonium methacrylate and poly-vinyl acetate, was incorporated into hydroxypropyl methyl cellulose (HPMC)-based matrix GFFE. This research studied the effect and interaction of the IPC-HPMC blending on the drug release of GFFE using a freely water-soluble drug, metformin HCl, under different threshold concentration levels and curing effect. The interaction between the IPC and HPMC was characterized using vibrational spectroscopy and thermal analyses under curing and swelling conditions. Anti-solvent followed by lyophilization had better physicochemical and physicomechanic properties than spray dying technique. The interaction was observed by a specific shifting of the vibrational peaks and alteration of the thermal behavior pattern. These effects altered the drug release behavior. Thereafter, the IPC reduced burst release effects in the initial time and during testing, and the IPC improved the HPMC matrix robustness under mechanical stress testing below threshold concentration of HPMC matrix formulated in the GFFE.

Synthetic Approaches to the New Drugs Approved During 2017.

New drugs introduced to the market every year represent privileged structures for particular biological targets. These new chemical entities (NCEs) provide insight into molecular recognition while serving as leads for designing future new drugs. This annual review describes the most likely process-scale synthetic approaches to 31 new chemical entities approved for the first time globally in 2017.

Preparation and Evaluation of Mosapride Citrate Dual-Release Dry Suspension.

In this paper, a novel formulation of dual-release dry suspension of mosapride citrate (DRDS-MC) was designed which can be quickly released in the stomach while having sustained-release effect. Co-grinding mixture of mosapride citrate (MC) together with L-HPC as hydrophilic excipient was prepared in order to improve the solubility of MC. The co-grinding mixture was characterized by solubility studies, DSC, X-RD, SEM, FTIR, and size distribution before the preparation of the DRDS-MC. Then, the co-grinding mixture was used to prepare DRDS-MC via wet granulation method. The evaluation of DRDS-MC was focused on physicochemical properties, intestinal absorption, and pharmacokinetics. The results of DSC, X-RD, SEM, FTIR, and size distribution indicated that MC resides in co-grinding mixture with no crystalline changes, hydrogen bonds made L-HPC greatly improving the solubility of MC. Then, the dissolution of DRDS-MC reached 70% in pH 1.2 within 2 h, and the 12-h dissolution of MC in pH 6.8 was nearly 80%. The sedimentation volume after 3 h was 0.94 and redispersibility was good. The linear regression equation between in vitro release of DRDS-MC and intestinal absorption fraction in rats was: Y = 29.215 + 47.535*X (r = 0.952). At last, pharmacokinetic studies in beagle dogs demonstrated that DRDS-MC has prolonged effect compared with commercial formulation Gasmotin as a reference. All results indicated that the DRDS-MC could be quickly released in the stomach while having sustained-release effect.

The synthesis and biological evaluation of a new bioactive metabolite of mosapride as a potential gastroprokinetic agent.

AIM: To synthesize the new bioactive metabolites of mosapride (R)-N-[2-hydroxy-3-(4-fluorobenzyl)amino]-propyl-5-chlorine-4-amino-2-ethoxyben-zamide (R-isomer) and (S)-N-[2-hydroxy-3-(4-fluorobenzyl)amino]-propyl-5-chlorine-4-amino-2-ethoxybenzamide (S-isomer) and evaluate their in vitro and in vivo pharmacological and pharmacokinetic profiles. RESULTS: S-isomer as a gastroprokinetic agent showed significant pharmacological activities in vivo. Furthermore, compared with the EC50 values for R-isomer and mosapride, S-isomer was proven to generate the same 5-HT4 receptor agonistic activity with a smaller amount. S-isomer exhibited significant differences in the pharmacokinetic properties, which indicate that higher absorption rate and extent compared with R-isomer. CONCLUSION: S-isomer might have great potential as a safe and effective prokinetic agent capable of lessening gastrointestinal symptoms and increasing quality of life.

Novel GLP-1/GLP-2 co-agonists display marked effects on gut volume and improves glycemic control in mice.

AIM: Analogues of several gastrointestinal peptide hormones have been developed into effective medicines for treatment of diseases such as type 2 diabetes mellitus (T2DM), obesity and short bowel syndrome (SBS). In this study, we aimed to explore whether the combination of glucagon-like peptide-1 (GLP-1) and glucagon-like peptide-2 (GLP-2) into a potent co-agonist could provide additional benefits compared to existing monotherapies. METHODS: A short-acting (GUB09-123) and a half-life extended (GUB09-145) GLP-1/GLP-2 co-agonist were generated using solid-phase peptide synthesis and tested for effects on food intake, body weight, glucose homeostasis, and gut proliferation in lean mice and in diabetic db/db mice. RESULTS: Sub-chronic administration of GUB09-123 to lean mice significantly reduced food intake, improved glucose tolerance, and increased gut volume, superior to monotherapy with the GLP-2 analogue teduglutide. Chronic administration of GUB09-123 to diabetic mice significantly improved glycemic control and showed persistent effects on gastric emptying, superior to monotherapy with the GLP-1 analogue liraglutide. Due to the short-acting nature of the molecule, no effects on body weight were observed, whereas a marked and robust intestinotrophic effect on mainly the small intestine volume and surface area was obtained. In contrast to GUB09-123, sub-chronic administration of a half-life extended GUB09-145 to lean mice caused marked dose-dependent effects on body weight while maintaining its potent intestinotrophic effect. CONCLUSION: Our data demonstrate that the GLP-1/GLP-2 co-agonists have effects on gut morphometry, showing a marked increase in intestinal volume and mucosal surface area. Furthermore, effects on glucose tolerance and long-term glycemic control are evident. Effects on body weight and gastric emptying are also observed depending on the pharmacokinetic properties of the molecule. We suggest that this novel co-agonistic approach could exemplify a novel concept for treatment of T2DM or SBS.

Stapled, Long-Acting Glucagon-like Peptide 2 Analog with Efficacy in Dextran Sodium Sulfate Induced Mouse Colitis Models.

Glucagon-like peptide 2 (GLP-2) is a hormone that has been shown to stimulate intestinal growth and attenuate intestinal inflammation. Despite being efficacious in a variety of animal models of disease, its therapeutic potential is hampered by the short half-life in vivo. We now describe a highly potent, stapled long-acting GLP-2 analog, peptide 10, that has a more than 10-fold longer half-life than teduglutide and improved intestinotrophic and anti-inflammatory effects in mouse models of DSS-induced colitis.

Respirable powder formulation of a shortened vasoactive intestinal peptide analog for treatment of airway inflammatory diseases.

The aim of present study was to develop a respirable powder (RP) of a shortened vasoactive intestinal peptide (VIP) analog for inhalation. VIP and C-terminally truncated VIP analogs were synthesized with a solid-phase method. A structure-activity relationship (SAR) study was carried out in terms with binding and relaxant activities of the peptides. Prepared RP formulation of a shortened VIP analog was physicochemically characterized by morphological, in vitro aerodynamic, and pharmacological assessments. The SAR study demonstrated that the N-terminal 23 amino acid residues were required for biological activity of VIP. Upon chemical modification of VIP(1-23), [R15, 20, 21 , L17 ]-VIP(1-23) was newly developed, which had higher binding activity in rat lung and smooth muscle relaxant effect in mouse stomach than VIP(1-23). The [R15, 20, 21 , L17 ]-VIP(1-23)-based RP, [R15, 20, 21 , L17 ]-VIP(1-23)/RP, exhibited fine in vitro inhalation performance. Airway inflammation evoked by sensitization of antigen in rats was attenuated by pre-treatment with the [R15, 20, 21 , L17 ]-VIP(1-23)/RP at a dose of 50 µg-[R15, 20, 21 , L17 ]-VIP(1-23)/rat as evidenced by a 70% reduction of recruited inflammatory cells in bronchoalveolar lavage fluid. On the basis of these results, [R15, 20, 21 , L17 ]-VIP(1-23)/RP might be a promising agent for treatment of airway inflammatory diseases.

An engineered cyclic peptide alleviates symptoms of inflammation in a murine model of inflammatory bowel disease.

Inflammatory bowel diseases (IBDs) are a set of complex and debilitating diseases for which there is no satisfactory treatment. Recent studies have shown that small peptides show promise for reducing inflammation in models of IBD. However, these small peptides are likely to be unstable and rapidly cleared from the circulation, and therefore, if not modified for better stability, represent non-viable drug leads. We hypothesized that improving the stability of these peptides by grafting them into a stable cyclic peptide scaffold may enhance their therapeutic potential. Using this approach, we have designed a novel cyclic peptide that comprises a small bioactive peptide from the annexin A1 protein grafted into a sunflower trypsin inhibitor cyclic scaffold. We used native chemical ligation to synthesize the grafted cyclic peptide. This engineered cyclic peptide maintained the overall fold of the naturally occurring cyclic peptide, was more effective at reducing inflammation in a mouse model of acute colitis than the bioactive peptide alone, and showed enhanced stability in human serum. Our findings suggest that the use of cyclic peptides as structural backbones offers a promising approach for the treatment of IBD and potentially other chronic inflammatory conditions.

Synthetic Approaches to the New Drugs Approved During 2015.

New drugs introduced to the market every year represent privileged structures for particular biological targets. These new chemical entities (NCEs) provide insight into molecular recognition while serving as leads for designing future new drugs. This annual review describes the most likely process-scale synthetic approaches to 29 new chemical entities (NCEs) that were approved for the first time in 2015.

Design of Magnetic Polymeric Particles as a Stimulus-Responsive System for Gastric Antimicrobial Therapy.

The treatment of peptic ulcers induced by H. pylori remains challenging due to the deep mucous layer location of bacteria preventing antimicrobial drug access. The present work aimed to design and evaluate in vitro dual responsive (both pH and magnetic field-sensitive) polymeric magnetic particles loaded with amoxicillin as a smart drug carrier for deep mucous layer penetration and in situ drug release. Magnetite particles were produced by the co-precipitation method and subsequently coated with the Eudragit®S100 and amoxicillin by using the spray-drying technique. The physicochemical characterization of the obtained particles was carried out by optical and scanning electron microscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, nitrogen adsorption/desorption isotherms, and vibrating sample magnetometry. Additionally, drug release tests and antibacterial activity tests were evaluated in vitro. Microparticles presented 17.2 ± 0.4 µm in size and their final composition was 4.3 ± 1.5% of amoxicillin, 87.0 ± 2.3% of Eudragit, and 9.0 ± 0.3% of magnetite. They were both pH and magnetic field responsive while presenting antimicrobial activity. On one side, magnetic field responsiveness of particles is expected to prompt them to reach bacterium niche in deep mucous layer by means of magnetic forces. On the other side, pH responsiveness is expected to enable drug release in the neutral pH of the deep mucous layer, preventing undesired delivery in the acidic gastric lumen. Smart microparticles were designed presenting both pH and magnetic field responsiveness as well as antimicrobial activity. These may be promising assets for peptic ulcer treatment.

Navigation in bile acid chemical space: discovery of novel FXR and GPBAR1 ligands.

Bile acids are signaling molecules interacting with nuclear receptors and membrane G-protein-coupled receptors. Among these receptors, the farnesoid X receptor (FXR) and the membrane G-coupled receptor (GPBAR1) have gained increasing consideration as druggable receptors and their exogenous dual regulation represents an attractive strategy in the treatment of enterohepatic and metabolic disorders. However, the therapeutic use of dual modulators could be associated to severe side effects and therefore the discovery of selective GPBAR1 and FXR agonists is an essential step in the medicinal chemistry optimization of bile acid scaffold. In this study, a new series of 6-ethylcholane derivatives modified on the tetracyclic core and on the side chain has been designed and synthesized and their in vitro activities on FXR and GPBAR1 were assayed. This speculation resulted in the identification of compound 7 as a potent and selective GPBAR1 agonist and of several derivatives showing potent dual agonistic activity.

Retro-inverso forms of gastrin5-12 are as biologically active as glycine-extended gastrin in vitro but not in vivo.

Non-amidated gastrin peptides such as glycine-extended gastrin (Ggly) are biologically active in vitro and in vivo and have been implicated in the development of gastric and colonic cancers. Previous studies have shown that the truncated form of Ggly, the octapeptide LE5AY, was still biologically active in vitro, and that activity was dependent on ferric ion binding but independent of binding to the cholecystokinin 2 (CCK2) receptor. The present work was aimed at creating more stable gastrin-derived 'super agonists' using retro-inverso technology. The truncated LE5AY peptide was synthesized using end protecting groups in three forms with l-amino acids (GL), d-amino acids (GD) or retro-inverso (reverse order with d-amino acids; GRI). All of these peptides bound ferric ions with a 2:1 (Fe: peptide) ratio. As predicted, Ggly, GL and GRI were biologically active in vitro and increased cell proliferation in mouse gastric epithelial (IMGE-5) and human colorectal cancer (DLD-1) cell lines, and increased cell migration in DLD-1 cells. These activities were likely via the same mechanism as Ggly since no CCK1 or CCK2 binding was identified, and GD remained inactive in all assays. Surprisingly, unlike Ggly, GL and GRI were not active in vivo. While Ggly stimulated colonic crypt height and proliferation rates in gastrin knockout mice, GL and GRI did not. The apparent lack of activity may be due to rapid clearance of these smaller peptides. Nevertheless further work designing and testing retro-inverso gastrins is warranted, as it may lead to the generation of super agonists that could potentially be used to treat patients with gastrointestinal disorders with reduced mucosal function.

A novel acylated form of (d-Ala(2))GIP with improved antidiabetic potential, lacking effect on body fat stores.

BACKGROUND: Rapid enzymatic degradation of the incretin hormone, glucose-dependent insulinotropic polypeptide (GIP), limits therapeutic use of the native peptide for diabetes. However, enzymatically stable analogues of GIP, such as (d-Ala(2))GIP, have been generated, but are still susceptible to renal filtration. METHODS: The present study examines the in vitro and in vivo biological actions of a novel, acylated GIP analogue, (d-Ala(2))GIP[Lys(37)PAL]. RESULTS: In BRIN-BD11 cells, (d-Ala(2))GIP[Lys(37)PAL] concentration-dependently stimulated (p<0.05 to p<0.001) insulin secretion at 5.6 and 16.7mM glucose. Intraperitoneal administration of (d-Ala(2))GIP[Lys(37)PAL] to normal mice 8h prior to a glucose load significantly reduced (p<0.05) the overall glycaemic excursion compared to controls, and increased (p<0.001) the insulinotropic response compared to (d-Ala(2))GIP and saline treated high fat control mice. Once daily administration of (d-Ala(2))GIP[Lys(37)PAL] for 21days in high fat fed mice did not affect energy intake, body weight or fat deposition. However, circulating blood glucose was significantly lower (p<0.05) accompanied by increased (p<0.05) insulin concentrations by day 21. In addition, (d-Ala(2))GIP[Lys(37)PAL] treatment significantly (p<0.01) reduced the overall glycaemic excursion and increased pancreatic insulin content (p<0.05) and the insulinotropic response (p<0.01) to an exogenous glucose challenge on day 21. Chronic treatment with (d-Ala(2))GIP[Lys(37)PAL] did not result in resistance to the metabolic effects of a bolus injection of native GIP. Finally, insulin sensitivity was significantly improved (p<0.001) in (d-Ala(2))GIP[Lys(37)PAL] treated mice compared to high fat controls. CONCLUSIONS: These data confirm that (d-Ala(2))GIP[Lys(37)PAL] is a stable, long-acting potent GIP agonist. GENERAL SIGNIFICANCE: (d-Ala(2))GIP[Lys(37)PAL] may be suitable for further evaluation and future clinical development.