Conversion of Olmesartan to Olmesartan Medoxomil, A Prodrug that Improves Intestinal Absorption, Confers Substrate Recognition by OATP2B1.

PURPOSE: Olmesartan medoxomil (olmesartan-MX), an ester-type prodrug of the angiotensin II receptor blocker (ARB) olmesartan, is predominantly anionic at intestinal pH. Human organic anion transporting polypeptide 2B1 (OATP2B1) is expressed in the small intestine and is involved in the absorption of various acidic drugs. This study was designed to test the hypothesis that OATP2B1-mediated uptake contributes to the enhanced intestinal absorption of olmesartan-MX, even though olmesartan itself is not a substrate of OATP2B1. METHODS: Tetracycline-inducible human OATP2B1- and rat Oatp2b1-overexpressing HEK 293 cell lines (hOATP2B1/T-REx-293 and rOatp2b1/T-REx-293, respectively) were established to characterize OATP2B1-mediated uptake. Rat jejunal permeability was measured using Ussing chambers. ARBs were quantified by liquid chromatography-tandem mass spectrometry. RESULTS: Significant olmesartan-MX uptake was observed in hOATP2B1/T-REx-293 and rOatp2b1/T-REx-293 cells, whereas olmesartan uptake was undetectable or much lower than olmesartan-MX uptake, respectively. Furthermore, olmesartan-MX exhibited several-fold higher uptake in Caco-2 cells and greater permeability in rat jejunum compared to olmesartan. Olmesartan-MX uptake in hOATP2B1/T-REx-293 cells and in Caco-2 cells was significantly decreased by OATP2B1 substrates/inhibitors such as 1 mM estrone-3-sulfate, 100 µM rifamycin SV, and 100 µM fluvastatin. Rat Oatp2b1-mediated uptake and rat jejunal permeability of olmesartan-MX were significantly decreased by 50 µM naringin, an OATP2B1 inhibitor. Oral administration of olmesartan-MX with 50 µM naringin to rats significantly reduced the area under the plasma concentration-time curve of olmesartan to 76.9%. CONCLUSION: Olmesartan-MX is a substrate for OATP2B1, and the naringin-sensitive transport system contributes to the improved intestinal absorption of olmesartan-MX compared with its parent drug, olmesartan.

Sacubitril/valsartan reverses cardiac structure and function in experimental model of hypertension-induced hypertrophic cardiomyopathy.

This study evaluated the effect of sacubtril/valsartan on cardiac remodeling, molecular and cellular adaptations in experimental (rat) model of hypertension-induced hypertrophic cardiomyopathy. Thirty Wistar Kyoto rats, 10 healthy (control) and 20 rats with confirmed hypertension-induced hypertrophic cardiomyopathy (HpCM), were used for this study. The HpCM group was further subdivided into untreated and sacubitril/valsartan-treated groups. Myocardial structure and function were assessed using echocardiography, Langendorff's isolated heart experiment, blood sampling and qualitative polymerase chain reaction. Echocardiographic examinations revealed protective effects of sacubitril/valsartan by improving left ventricular internal diameter in systole and diastole and fractional shortening. Additionally, sacubitril/valsartan treatment decreased systolic and diastolic blood pressures in comparison with untreated hypertensive rats. Moreover, sacubitril/valsartan treatment reduced oxidative stress and apoptosis (reduced expression of Bax and Cas9 genes) compared to untreated rats. There was a regular histomorphology of cardiomyocytes, interstitium, and blood vessels in treated rats compared to untreated HpCM rats which expressed hypertrophic cardiomyocytes, with polymorphic nuclei, prominent nucleoli and moderately dilated interstitium. In experimental model of hypertension-induced hypertrophic cardiomyopathy, sacubitril/valsartan treatment led to improved cardiac structure, haemodynamic performance, and reduced oxidative stress and apoptosis. Sacubitril/valsartan thus presents as a potential therapeutic strategy resulted in hypertension-induced hypertrophic cardiomyopathy.

Serum Concentrations of Losartan Metabolites Correlate With Improved Physical Function in a Pilot Study of Prefrail Older Adults.

Losartan is an oral antihypertensive agent that is rapidly metabolized to EXP3174 (angiotensin-subtype-1-receptor blocker) and EXP3179 (peroxisome proliferator-activated receptor gamma [PPARγ] agonist), which was shown in animal studies to reduce inflammation, enhance mitochondrial energetics, and improve muscle repair and physical performance. We conducted an exploratory pilot study evaluating losartan treatment in prefrail older adults (age 70-90 years, N = 25). Participants were randomized to control (placebo) or treatment (daily oral losartan beginning at 25 mg per day and increasing every 8 weeks) for a total of 6 months. Fatigue, hyperkalemia, and hypotension were the most observed side effects of losartan treatment. Participants in the losartan group had an estimated 89% lower odds of frailty (95% confidence interval [CI]: 18% to 99% lower odds, p = .03), with a 0.3-point lower frailty score than the placebo group (95% CI: 0.01-0.5 lower odds, p = .04). Frailty score was also negatively associated with serum losartan and EXP3179 concentrations. For every one standard deviation increase in EXP3179 (ie, 0.0011 ng/µL, based on sample values above detection limit) and EXP3174 (ie, 0.27 ng/µL, based on sample values above detection limit), there was a 0.0035 N (95% CI: 0.0019-0.0051, p < .001) and a 0.0027 N (95% CI: 0.00054-0.0043, p = .007) increase in average knee strength, respectively.

Explanation of the Formation of Complexes between Representatives of Oxazolidinones and HDAS-ß-CD Using Molecular Modeling as a Complementary Technique to cEKC and NMR.

Molecular modeling (MM) results for tedizolid and radezolid with heptakis-(2,3-diacetyl-6-sulfo)-ß-cyclodextrin (HDAS-ß-CD) are presented and compared with the results previously obtained for linezolid and sutezolid. The mechanism of interaction of chiral oxazolidinone ligands belonging to a new class of antibacterial agents, such as linezolid, tedizolid, radezolid, and sutezolid, with HDAS-ß-CD based on capillary electrokinetic chromatography (cEKC), nuclear magnetic resonance (NMR) spectroscopy, and MM methods was described. Principles of chiral separation of oxazolidinone analogues using charged single isomer derivatives of cyclodextrin by the cEKC method were presented, including the selection of the optimal chiral selector and separation conditions, complex stoichiometry, and binding constants, which provided a comprehensive basis for MM studies. In turn, NMR provided, where possible, direct information on the geometry of the inclusion complexes and also provided the necessary structural information to validate the MM calculations. Consequently, MM contributed to the understanding of the structure of diastereomeric complexes, the thermodynamics of complexation, and the visualization of their structures. The most probable mean geometries of the studied supramolecular complexes and their dynamics (geometry changes over time) were determined by molecular dynamics methods. Oxazolidinone ligands have been shown to complex mainly the inner part of cyclodextrin, while the external binding is less privileged, which is consistent with the conclusions of the NMR studies. Enthalpy values of binding of complexes were calculated using long-term molecular dynamics in explicit water as well as using molecular mechanics, the Poisson-Boltzmann or generalized Born, and surface area continuum solvation (MM/PBSA and MM/GBSA) methods. Computational methods predicted the effect of changes in pH and composition of the solution on the strength and complexation process, and it adapted the conditions selected as optimal during the cEKC study. By changing the dielectric constant in the MM/PBSA and MM/GBSA calculations, the effect of changing the solution to methanol/acetonitrile was investigated. A fairly successful attempt was made to predict the chiral separation of the oxazolidinones using the modified cyclodextrin by computational methods.

Discovery of Encequidar, First-in-Class Intestine Specific P-glycoprotein Inhibitor.

Many chemotherapeutics, such as paclitaxel, are administered intravenously as they suffer from poor oral bioavailability, partly because of efflux mechanism of P-glycoprotein in the intestinal epithelium. To date, no drug has been approved by the U.S. Food and Drug Administration (FDA) that selectively blocks this efflux pump. We sought to identify a compound that selectively inhibits P-glycoprotein in the gastrointestinal mucosa with poor oral bioavailability, thus eliminating the issues such as bone marrow toxicity associated with systemic inhibition of P-glycoprotein. Here, we describe the discovery of highly potent, selective, and poorly orally bioavailable P-glycoprotein inhibitor 14 (encequidar). Clinically, encequidar was found to be well tolerated and minimally absorbed; and importantly, it enabled the oral delivery of paclitaxel.

In Vitro Evidence of Potential Interactions between CYP2C8 and Candesartan Acyl-ß-D-glucuronide in the Liver.

Growing evidence suggests that certain glucuronides function as potent inhibitors of CYP2C8. We previously reported the possibility of drug-drug interactions between candesartan cilexetil and paclitaxel. In this study, we evaluated the effects of candesartan N2-glucuronide and candesartan acyl-ß-D-glucuronide on pathways associated with the elimination of paclitaxel, including those involving organic anion-transporting polypeptide (OATP) 1B1, OATP1B3, CYP2C8, and CYP3A4. UDP-glucuronosyltransferase (UGT) 1A10 and UGT2B7 were found to increase candesartan N2-glucuronide and candesartan acyl-ß-D-glucuronide formation in a candesartan concentration-dependent manner. Additionally, the uptake of candesartan N2-glucuronide and candesartan acyl-ß-D-glucuronide by cells stably expressing OATPs is a saturable process with K m of 5.11 and 12.1 µM for OATP1B1 and 28.8 and 15.7 µM for OATP1B3, respectively; both glucuronides exhibit moderate inhibition of OATP1B1/1B3. Moreover, the hydroxylation of paclitaxel was evaluated using recombinant CYP3A4 and CYP3A5. Results show that candesartan, candesartan N2-glucuronide, and candesartan acyl-ß-D-glucuronide inhibit the CYP2C8-mediated metabolism of paclitaxel, with candesartan acyl-ß-D-glucuronide exhibiting the strongest inhibition (IC50 is 18.9 µM for candesartan acyl-ß-D-glucuronide, 150 µM for candesartan, and 166 µM for candesartan N2-glucuronide). However, time-dependent inhibition of CYP2C8 by candesartan acyl-ß-D-glucuronide was not observed. Conversely, the IC50 values of all the compounds are comparable for CYP3A4. Taken together, these data suggest that candesartan acyl-ß-D-glucuronide is actively transported by OATPs into hepatocytes, and drug-drug interactions may occur with coadministration of candesartan and CYP2C8 substrates, including paclitaxel, as a result of the inhibition of CYP2C8 function. SIGNIFICANCE STATEMENT: This study demonstrates that the acyl glucuronidation of candesartan to form candesartan acyl-ß-D-glucuronide enhances CYP2C8 inhibition while exerting minimal effects on CYP3A4, organic anion-transporting polypeptide (OATP) 1B1, and OATP1B3. Thus, candesartan acyl-ß-D-glucuronide might represent a potential mediator of drug-drug interactions between candesartan and CYP2C8 substrates, such as paclitaxel, in clinical settings. This work adds to the growing knowledge regarding the inhibitory effects of glucuronides on CYP2C8.

Multicomponent Synthesis, Binding Mode, and Structure-Activity Relationship of Selective Histone Deacetylase 6 (HDAC6) Inhibitors with Bifurcated Capping Groups.

Histone deacetylase 6 (HDAC6) is an emerging target for the treatment of cancer, neurodegenerative diseases, inflammation, and other diseases. Here, we present the multicomponent synthesis and structure-activity relationship of a series of tetrazole-based HDAC6 inhibitors. We discovered the hit compound NR-160 by investigating the inhibition of recombinant HDAC enzymes and protein acetylation. A cocrystal structure of HDAC6 complexed with NR-160 disclosed that the steric complementarity of the bifurcated capping group of NR-160 to the L1 and L2 loop pockets may be responsible for its HDAC6-selective inhibition. While NR-160 displayed only low cytotoxicity as a single agent against leukemia cell lines, it augmented the apoptosis induction of the proteasome inhibitor bortezomib in combination experiments significantly. Furthermore, a combinatorial high-throughput drug screen revealed significantly enhanced cytotoxicity when NR-160 was used in combination with epirubicin and daunorubicin. The synergistic effect in combination with bortezomib and anthracyclines highlights the potential of NR-160 in combination therapies.

The design, synthesis and evaluation of 2-aminobenzoxazole analogues as potent and orally efficacious ChemR23 inhibitors.

We previously reported 2-aminobenzoxazole analogue 1 as a potent ChemR23 inhibitor. The compound showed inhibitory activity against chemerin-induced calcium signaling through ChemR23 internalization in CAL-1 cells, which are cell lines of plasmacytoid dendric cells (pDCs). Furthermore, compound 2 inhibited chemotaxis of CAL-1 triggered by chemerin in vitro. However, we noted a difference in the ChemR23 response to our inhibitor between rodents and non-rodents in a previous study. To address this issue, we performed optimization of ChemR23 inhibitors using CAL-1 cells endogenously expressing human ChemR23 and conducted a pharmacokinetics study in cynomolgus monkeys. Various substituents at the 4-position of the benzoxazole ring exhibited potent in vitro bioactivity, while those at the 6-position were not tolerated. Among substituents, a carboxyl group was identified as key for improving the oral bioavailability in cynomolgus monkeys. Compound 38a with the acidic part changed from a tetrazole group to a 1,2,4-oxadiazol-5-one group to improve bioactivity and pharmacokinetic parameters exhibited inhibitory activity against chemerin-induced chemotaxis in vitro. In addition, we confirmed the ChemR23 internalization of pDCs by compound 38a orally administered to cynomolgus monkeys. These 2-aminobenzoxazole-based ChemR23 inhibitors may be useful as novel immunotherapeutic agents capable of suppressing the migration of pDCs, which are known to be major producers of type I interferons in the lesion area of certain autoimmune diseases, such as systemic lupus erythematosus and psoriasis.

Immobilized angiotensin II type I receptor: A powerful method of high throughput screening for antihypertensive compound identification through binding interaction analysis.

The enormous growth in drug discovery paradigm has necessitated continuous exploration of new methods for drug-protein interaction analysis. To enhance the role of these methodologies in designing rational drugs, this work extended an immobilized angiotensin II type I receptor (AT1R) based affinity chromatography in antihypertensive compound identification. We fused haloalkane dehalogenase at C-terminus of AT1R and expressed the fusion receptor in E. coli. The expressed receptor was covalently immobilized onto 8.0 µm microspheres by mixing the cell lysate with 6-chlorocaproic acid-modified amino polystyrene microspheres. The immobilized AT1R was utilized for thermodynamic and kinetic interaction analysis between the receptor and four specific ligands. Following confirmation of these interactions by molecular docking, we identified puerarin and rosmarinic acid by determining their binding to the receptor. Azilsartan, candesartan, valsartan and olmesartan displayed two kinds of binding sites to AT1R by injection amount-dependent method. By molecular docking, we recognize the driving forces of the interaction as electrostatic interaction, hydrogen bonds and van der Waals force. The dissociation rate constants (kd) of azilsartan, candesartan, valsartan and olmesartan to AT1R were 0.01138 ± 0.003, 0.05142 ± 0.003, 0.07547 ± 0.004 and 0.01310 ± 0.005 min-1 by peak profiling assay. Comparing with these parameters, puerarin and rosmarinic acid presented lower affinity (KA: 0.12 × 104 and 1.5 × 104/M) and slower kinetics (kd: 0.6864 ± 0.03 and 0.3005 ± 0.01 min-1) to the receptor. These results, taking together, indicated that the immobilized AT1R has the capacity to probe antihypertensive compounds.

Simultaneous quantification of candesartan and irbesartan in rabbit eye tissues by liquid chromatography-tandem mass spectrometry.

Diabetic retinopathy is a major cause of vision loss in adults. Novel eye-drop formulations of candesartan and irbesartan are being developed for its cure or treatment. To support a preclinical trial in rabbits, it was critical to develop and validate a new LC-MS/MS method for simultaneous quantification of candesartan and irbesartan in rabbit eye tissues (cornea, aqueous humor, vitreous body and retina/choroid). Eye tissue samples were first homogenized in H2 O-diluted rabbit plasma. The candesartan and irbesartan in the supernatants together with their respective internal standards (candesartan-d4 and irbesartan-d4 ) were extracted by solid-phase extraction. The extracted samples were injected onto a C18 column for gradient separation. The MS detection was in the positive electrospray ionization mode using the multiple reaction monitoring transitions of m/z 441 → 263, 445 → 267, 429 → 207, and 433 → 211 for candesartan, candesartan-d4 , irbesartan and irbesartan-d4 , respectively. For the validated concentration ranges (2-2000 and 5-5000 ng/g for candesartan and irbesartan, respectively), the within-run and between-run accuracies (% bias) were within the range of -8.0-10.0. The percentage CV ranged from 0.6 to 7.3. There was no significant matrix interference nor matrix effect from different eye tissues and different rabbits. The validated method was successfully used in the Good Laboratory Practice (GLP) study of rabbits.

A New Synthesis of Poly Heterocyclic Compounds Containing [1,2,4]triazolo and [1,2,3,4]tetrazolo Moieties and their DFT Study as Expected Anti-cancer Reagents.

BACKGROUND: 2-amino-3-cyanopyridines are good starting reagents that have been used in synthesis of many heterocyclic compounds such as pyridopyrimidines, [1,2,4]triazolo and [1,2,3,4] tetrazolo derivatives which have biological activities as anti-microbial and cytotoxic activities. Meanwhile [1,2,4]triazolo and [1,2,3,4]tetrazolo derivatives are well known to possess many physiological activities, such as anticancer , antifungal, muscle relaxant, hypnotic, anti-inflammatory, diuretic and antihypertensive activities. A broad class of heterocyclic compounds has been studied to demonstrate their biological activity on the structures of DNA and RNA. Several of important functions make Tankyrases acts as targets in potential drug. OBJECTIVE: The article focuses on synthesis of [1,2,4]triazolo and [1,2,3,4]tetrazolo derivatives and their theoretical calculations that suggest they are anti-cancer substances. MATERIALS AND METHODS: DFT and computational studies were performed on the structural properties of experimental molecules experimentally, and significant theoretical calculations were performed based on density functional theory (DFT) with Becke's three-parameter exchange function21-22 of correlation functional Lee Yang Parr (B3LYP) with the basis set 6-31G (d,p) using Gaussian 03 software23. Geometrical parameters of the optimized structures were calculated and also the charge on each atom (Mulliken charge). Chemcraft program24 was used to visualize the optimized structure and ChemBio3D ultra 12.0 was used to visualize the highest occupied and lowest unoccupied molecular orbitals. RESULTS: Preliminary screening in five studied ligands acts as inhibitors for different active sites along the target. The molecular docking study also revealed that the compound 6c was the most effective compounds in inhibiting Tankyrase I enzyme (2rf5), this result can help strongly in inhibition of carcinogenic cells and cancer treatment. CONCLUSION: We have described a new practical cyclocondensation synthesis for a series of [1,2,4]triazolo[4,3- c]pyrido[3,2-e] pyrimidine and pyrido[2',3':4,5] pyrimido[6,1-c][1,2,4] triazine from 2-amino-3-cyano-4.6- diarylpyridines. Also polyheterocyclic compounds containing [1,2,4]triazolo and [1,2,3,4]tetrazolo moieties were also synthesized through the reactions of 3-hydrazino-8,10-diaryl [1,2,4]triazolo[4,3-c]pyrido[3,2- e]pyrimidine with both formic acid and the formation of diazonuim salt respectively. Newly synthesized heterocycles structures were confirmed using elemental analysis, IR, 1H-NMR, 13C-NMR and mass spectral data. DFT and computational studies were carried out on five of the synthesized poly heterocyclic compounds to show their structural and geometrical parameters involved in the study. Molecular docking using Tankyrase I enzyme as a target showed how the studied heterocyclic compounds act as a ligand interacting most of active sites on Tankyrase I with a type of interactions specified for H-bonding and VDW. We investigated that the five studied ligands act as inhibitors for different active sites along the target. The molecular docking study also revealed that the compound 6c was the most effective compounds in inhibiting Tankyrase I enzyme (2rf5), this result can help strongly in inhibition of carcinogenic cells and cancer treatment.

Bronchodilation induced by PGE2 is impaired in Group III pulmonary hypertension.

BACKGROUND AND PURPOSE: In patients with pulmonary hypertension (PH) associated with lung disease and/or hypoxia (Group III), decreased pulmonary vascular tone and tissue hypoxia is therapeutically beneficial. PGE2 and PGI2 induce potent relaxation of human bronchi from non-PH (control) patients via EP4 and IP receptors, respectively. However, the effects of PGE2 /PGI2 and their mimetics on human bronchi from PH patients are unknown. Here, we have compared relaxant effects of several PGI2 -mimetics approved for treating PH Group I with several PGE2 -mimetics, in bronchial preparations derived from PH Group III and control patients. EXPERIMENTAL APPROACH: Relaxation of bronchial muscle was assessed in samples isolated from control and PH Group III patients. Expression of prostanoid receptors was analysed by western blot and real-time PCR, and endogenous PGE2 , PGI2 , and cAMP levels were determined by ELISA. KEY RESULTS: Maximal relaxations induced by different EP4 receptor agonists (PGE2 , L-902688, and ONO-AE1-329) were decreased in human bronchi from PH patients, compared with controls. However, maximal relaxations produced by PGI2 -mimetics (iloprost, treprostinil, and beraprost) were similar for both groups of patients. Both EP4 and IP receptor protein and mRNA expressions were significantly lower in human bronchi from PH patients. cAMP levels significantly correlated with PGI2 but not with PGE2 levels. CONCLUSION AND IMPLICATIONS: The PGI2 -mimetics retained maximal bronchodilation in PH Group III patients, whereas bronchodilation induced by EP4 receptor agonists was decreased. Restoration of EP4 receptor expression in airways of PH Group III patients with respiratory diseases could bring additional therapeutic benefit.

Aldo-keto Reductase Metabolizes Glyphosate and Confers Glyphosate Resistance in Echinochloa colona.

Glyphosate, the most commonly used herbicide in the world, controls a wide range of plant species, mainly because plants have little capacity to metabolize (detoxify) glyphosate. Massive glyphosate use has led to world-wide evolution of glyphosate-resistant (GR) weed species, including the economically damaging grass weed Echinochloa colona An Australian population of E colona has evolved resistance to glyphosate with unknown mechanisms that do not involve the glyphosate target enzyme 5-enolpyruvylshikimate-3-P synthase. GR and glyphosate-susceptible (S) lines were isolated from this population and used for resistance gene discovery. RNA sequencing analysis and phenotype/genotype validation experiments revealed that one aldo-keto reductase (AKR) contig had higher expression and higher resultant AKR activity in GR than S plants. Two full-length AKR (EcAKR4-1 and EcAKR4-2) complementary DNA transcripts were cloned with identical sequences between the GR and S plants but were upregulated in the GR plants. Rice (Oryza sativa) calli and seedlings overexpressing EcAKR4-1 and displaying increased AKR activity were resistant to glyphosate. EcAKR4-1 expressed in Escherichia coli can metabolize glyphosate to produce aminomethylphosphonic acid and glyoxylate. Consistent with these results, GR E colona plants exhibited enhanced capacity for detoxifying glyphosate into aminomethylphosphonic acid and glyoxylate. Structural modeling predicted that glyphosate binds to EcAKR4-1 for oxidation, and metabolomics analysis of EcAKR4-1 transgenic rice seedlings revealed possible redox pathways involved in glyphosate metabolism. Our study provides direct experimental evidence of the evolution of a plant AKR that metabolizes glyphosate and thereby confers glyphosate resistance.

Interaction Between Sacubitril and Valsartan in Preventing Heart Failure Induced by Aortic Valve Insufficiency in Rats.

BACKGROUND: Synergistic interactions between neprilysin inhibition (NEPi) with sacubitril and angiotensin receptor type1 blockade (ARB) with valsartan have been implicated in improvement of left ventricular (LV) contractility, relaxation, exercise tolerance, and fibrosis in preexisting heart failure (HF) induced by aortic valve insufficiency (AVI). It is not known whether this pharmacologic synergy can prevent cardiovascular pathology in a similar AVI model. Our aim was to investigate the pharmacology of sacubitril/valsartan in an experimental setting with therapy beginning immediately after creation of AVI. METHODS: HF was induced through partial disruption of the aortic valve in rats. Therapy began 3 hours after valve disruption and lasted 8 weeks. Sacubitril/valsartan (68 mg/kg), valsartan (31 mg/kg), sacubitril (31 mg/kg), or vehicle were administered daily via oral gavage (N=8 in each group). Hemodynamic assessments were conducted using Millar technology, and an exercise tolerance test was conducted using a rodent treadmill. RESULTS: Only sacubitril/valsartan increased total arterial compliance and ejection fraction (EF). Therapies with sacubitril/valsartan and valsartan similarly improved load-dependent (dP/dtmax) and load independent indices (Ees) of LV contractility, and exercise tolerance, whereas sacubitril did not. None of the therapies improved LV relaxation (dP/dtmin), whereas all reduced myocardial fibrosis. CONCLUSIONS: 1) The synergistic interaction between NEPi and ARB in early therapy with sacubitril/valsartan leads to increased total arterial compliance and EF. 2) Improvement in indices of LV contractility, and exercise tolerance with sacubitril/valsartan is likely because of ARB effect of valsartan. 3) All three therapies provided antifibrotic effects, suggesting both ARB and NEPi are capable of reducing myocardial fibrosis.

Fast analysis of glufosinate, glyphosate and its main metabolite, aminomethylphosphonic acid, in edible oils, by liquid chromatographycoupled with electrospray tandem mass spectrometry.

A method has been developed for the rapid, specific, accurate, precise and sensitive determination of glufosinate, glyphosate and its major metabolite, aminomethylphosphonic acid, in edible oils, by liquid chromatography coupled to tandem mass spectrometry. Oils were extracted with acidified water (1% formic acid), and the extracts were directly injected into an LC using a Hypercarb column as the stationary phase. The analytes were eluted by a mobile phase of methanol and water containing 1% acetic acid, and they were ionised by electrospray ionisation in negative ion mode. The method was validated and limits of quantification ranged from 5 µg kg-1 (aminomethylphosphonic acid) to 10 µg kg-1 (glyphosate and glufosinate). Three concentrations (10, 50 and 100 µg kg-1) were selected to perform recovery studies. Mean recoveries ranged from 81.4% to 119.4%. Intra and inter-day precision were lower than 19%. Different edible oils were analysed, and no residues of the studied herbicides were detected above limits of quantification.

Synthesis and evaluation of the HIF-1α inhibitory activities of novel ursolic acid tetrazole derivatives.

The hypoxia-inducible factor-1α (HIF-1α) pathway has been implicated in tumor angiogenesis, growth, and metastasis. Therefore, the inhibition of this pathway is an important therapeutic target for the treatment of various types of cancers. Here, we designed and synthesized 31 ursolic acid (UA) derivatives containing a tetrazole moiety and evaluated them for their potential anti-tumor activities as HIF-1α transcriptional inhibitors. Of these, compound 14d (IC50 0.8 ±â€¯0.2 µM) displayed the most potent activity and compounds 14a (IC50 4.7 ±â€¯0.2 µM) exhibited the most promising biological profile. Analysis of the structure-activity relationships of these compounds with HIF-1α suggested that the presence of a tetrazole group located at C-28 of the UA derivatives was critical for their inhibitory activities.

Glyphosate, but not its metabolite AMPA, alters the honeybee gut microbiota.

The honeybee (Apis mellifera) has to cope with multiple environmental stressors, especially pesticides. Among those, the herbicide glyphosate and its main metabolite, the aminomethylphosphonic acid (AMPA), are among the most abundant and ubiquitous contaminant in the environment. Through the foraging and storing of contaminated resources, honeybees are exposed to these xenobiotics. As ingested glyphosate and AMPA are directly in contact with the honeybee gut microbiota, we used quantitative PCR to test whether they could induce significant changes in the relative abundance of the major gut bacterial taxa. Glyphosate induced a strong decrease in Snodgrassella alvi, a partial decrease of a Gilliamella apicola and an increase in Lactobacillus spp. abundances. In vitro, glyphosate reduced the growth of S. alvi and G. apicola but not Lactobacillus kunkeei. Although being no bee killer, we confirmed that glyphosate can have sublethal effects on the honeybee microbiota. To test whether such imbalanced microbiota could favor pathogen development, honeybees were exposed to glyphosate and to spores of the intestinal parasite Nosema ceranae. Glyphosate did not significantly enhance the effect of the parasite infection. Concerning AMPA, while it could reduce the growth of G. apicola in vitro, it did not induce any significant change in the honeybee microbiota, suggesting that glyphosate is the active component modifying the gut communities.

Pharmaceutical Cocrystal: A Novel Approach to Tailor the Biopharmaceutical Properties of a Poorly Water Soluble Drug.

BACKGROUND: The present study reports the formation of a cocrystal of candesartan with the coformer methyl paraben, its characterization and determination of its bioavailability. Candesartan is a poorly water-soluble drug having an anti-hypertensive activity. The recent patents on the cocrystals of the drugs Progesterone (US9982007B2), Epalrestat (EP2326632B1), Gefitinib (WO2015170345A1), and Valsartan (CN102702118B) for enhancement of solubility, helped in selection of the drug for this work. METHODS: Candesartan cocrystal was prepared by solution crystallization method. The formation of a new crystalline phase was characterized by Differential Scanning Calorimetry (DSC), Fourier Transform Infrared (FTIR) and Powder X-ray Diffraction (PXRD) studies. Saturation solubility studies were carried out in ethanol: water (50:50 % v/v) mixture. The dissolution studies were conducted in 900 ml of phosphate buffer at pH 7.4(I.P.) with 0.7% w/w of Tween 20 at 50 rpm, maintained at a temperature of 37±0.5°C in a USP type II dissolution apparatus. The pharmacokinetic behavior of candesartan and its cocrystal was thereof investigated in male Wistar rats. RESULTS: There was 6.94 fold enhancement in the solubility of candesartan after its cocrystallization. The dissolution profile of the cocrystal exhibited significant improvement in solubility at 60 and 120 minutes and it remained stable in ethanol: water (50:50%v/v) mixture for 48 h as confirmed by PXRD studies. The AUC0-24of the cocrystal was found to be increased by 2.9 fold in terms of bioavailability as compared to the pure drug. CONCLUSION: The prepared cocrystal was found to be relatively more soluble than the pure drug and also showed an enhanced oral bioavailability as compared to the pure drug.

Improved radiosynthesis and preliminary in vivo evaluation of the 11C-labeled tetrazine [11C]AE-1 for pretargeted PET imaging.

Pretargeted nuclear imaging based on the ligation between tetrazines and nano-sized targeting agents functionalized with trans-cyclooctene (TCO) has recently been shown to improve both imaging contrast and dosimetry in nuclear imaging of nanomedicines. Herein, we describe the improved radiosynthesis of a 11C-labeled tetrazine ([11C]AE-1) and its preliminary evaluation in both mice and pigs. Pretargeted imaging in mice was carried out using both a new TCO-functionalized polyglutamic acid and a previously reported TCO-functionalized bisphosphonate system as targeting agents. Unfortunately, pretargeted imaging was not successful using these targeting agents in pair with [11C]AE-1. However, brain imaging in pig indicated that the tracer crossed the blood-brain-barrier. Hence, we suggest that this tetrazine scaffold could be used as a starting point for the development of pretargeted brain imaging, which has so far been a challenging task.