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Bedaquiline (BDQ) is a drug used to treat multidrug-resistant tuberculosis (MDR-TB). It exhibits exposure-dependent efficacy in eliminating Mycobacterium tuberculosis (Mtb). An easy, efficient and precise reverse-phase ultrafast liquid chromatography (RP-UFLC) method was developed to validate the free base of the antitubercular medication BDQ. BDQ was separated using a 10:90 v/v mobile phase of ammonium acetate buffer solution (pH = 5.4) and high-performance liquid chromatography-grade methanol, with a flow rate of 1.5 mL/min and a UV detection wavelength of 226 nm. By using the Box-Behnken design (BBD) and response surface methodology (RSM), the method was optimised by varying critical analytical attributes (CAA) and critical performance attributes (CPAs) namely ammonium acetate fraction (%), flow rate (ml/min), buffer system molarity (M) and pH. BDQ was eluted at 7.5 min utilising isocratic elution. The method was linear in the concentration range of 0.5-300 μg/mL with limit of detection values of 0.039 μg/mL and limit of quantification of 0.12 μg/mL. The results indicate that this validated method can be used as an alternative method for assay of BDQ., (© 2024 The Author(s). Biomedical Chromatography published by John Wiley & Sons Ltd.)

Liposomal formulations of antibiotics for inhalation offer the potential for the delivery of high drug doses, controlled drug release kinetics in the lung, and an excellent safety profile. In this study, we evaluated the in vivo performance of a liposomal formulation for the poorly soluble, antituberculosis agent, bedaquiline. Bedaquiline was encapsulated within monodisperse liposomes of ∼70 nm at a relatively high drug concentration (∼3.6 mg/mL). Formulations with or without fucose residues, which bind to C-type lectin receptors and mediate a preferential binding to macrophage mannose receptor, were prepared, and efficacy was assessed in an in vivo C3HeB/FeJ mouse model of tuberculosis infection (H37Rv strain). Seven intranasal instillations of 5 mg/kg bedaquiline formulations administered every second day resulted in a significant reduction in lung burden (∼0.4-0.6 Δlog 10 CFU), although no differences between fucosylated and nonfucosylated formulations were observed. A pharmacokinetic study in healthy, noninfected Balb/c mice demonstrated that intranasal administration of a single dose of 2.5 mg/kg bedaquiline liposomal formulation (fucosylated) improved the lung bioavailability 6-fold compared to intravenous administration of the same formulation at the same dose. Importantly, intranasal administration reduced systemic concentrations of the primary metabolite, N -desmethyl-bedaquiline (M2), compared with both intravenous and oral administration. This is a clinically relevant finding as the M2 metabolite is associated with a higher risk of QT-prolongation in predisposed patients. The results clearly demonstrate that a bedaquiline liposomal inhalation suspension may show enhanced antitubercular activity in the lung while reducing systemic side effects, thus meriting further nonclinical investigation.

Bedaquiline (BDQ), a first-in-class diarylquinoline anti-tuberculosis drug, and its analogue, TBAJ-587, prevent the growth and proliferation of Mycobacterium tuberculosis by inhibiting ATP synthase 1,2 . However, BDQ also inhibits human ATP synthase 3 . At present, how these compounds interact with either M. tuberculosis ATP synthase or human ATP synthase is unclear. Here we present cryogenic electron microscopy structures of M. tuberculosis ATP synthase with and without BDQ and TBAJ-587 bound, and human ATP synthase bound to BDQ. The two inhibitors interact with subunit a and the c-ring at the leading site, c-only sites and lagging site in M. tuberculosis ATP synthase, showing that BDQ and TBAJ-587 have similar modes of action. The quinolinyl and dimethylamino units of the compounds make extensive contacts with the protein. The structure of human ATP synthase in complex with BDQ reveals that the BDQ-binding site is similar to that observed for the leading site in M. tuberculosis ATP synthase, and that the quinolinyl unit also interacts extensively with the human enzyme. This study will improve researchers' understanding of the similarities and differences between human ATP synthase and M. tuberculosis ATP synthase in terms of the mode of BDQ binding, and will allow the rational design of novel diarylquinolines as anti-tuberculosis drugs., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

Bedaquiline (BQ) solid lipid nanoparticles (SLNs), which have previously been formulated for parenteral administration, have a risk of patient non-compliance in treating tuberculosis. This research presents a strategy to develop BQ SLNs for oral delivery to improve patient adherence, The upper and lower levels for the formulation excipients were generated from screening experiments. Using 4 input factors (BQ, lecithin, Tween 80, and PEG), a full factorial design from 3 × 2x2 × 2 experiments was randomly arranged to investigate 3 response variables: Particle size distribution (PSD), polydispersity index (PdI), and zeta potential (ZP). High shear homogenization was used to mix the solvent and aqueous phases, with 15% sucrose as a cryoprotectant. The response variables were assessed using a zeta sizer while TEM micrographs confirmed the PSD data. Solid-state assessments were conducted using powdered X-ray diffraction and scanning electron microscopy (SEM) imaging. A comparative invitro assessment was used to determine drug release from an equivalent dose of BQ free base powder and BQ-SLN, both packed in hard gelatin capsules. The sonicated formulations obtained significant effects for PSD, PdI, and ZP. The p-values (0.0001 for PdI, 0.0091 for PSD) for BQ as an independent variable in the sonicated formulation were notably higher than those in the unsonicated formulation (0.1336 for PdI, 0.0117 for PSD). The SEM images were between 100 - 400 nm and delineated nanocrystals of BQ embedded in the lipid matrix. The SLN formulation provides higher drug levels over the drug's free base; a similarity factor (f2 = 18.3) was estimated from the dissolution profiles., (© 2024. The Author(s), under exclusive licence to American Association of Pharmaceutical Scientists.)

Bedaquiline fumarate (BQF) is classified as a BCS class II drug and has poor water solubility and dissolution rate, which ultimately compromises bioavailability. The objective of this study is to improve the biopharmaceutical properties of BQF through a solid dispersion system by using Soluplus ® . Two solid dispersion systems were prepared i.e. binary solid dispersion (BSD) and ternary solid dispersion (TSD) where 14.31-fold and 20.43-fold increase in solubility of BQF was observed with BSD and TSD in comparison to BQF. In our previous research work, we explored the BSD and TSD of BQF with a crystalline polymer, poloxamer 188, which showed an increment in the solubility of BQF. In the current research, amorphous Soluplus ® polymer was selected to formulate BSD and TSD with BQF and showed higher solubility than poloxamer 188. The various solid and liquid state characterization results confirmed the presence of an amorphous form of BQF inside solid dispersion. The Fourier transform infrared spectroscopy showed no chemical interactions between BQF and polymer. The cellular uptake results demonstrated higher uptake in Caco-2 cell lines. Pharmacokinetic studies showed enhanced solubility and bioavailability of TSDs. Hence, the present research shows a promising formulation strategy for enhancing the biopharmaceutical performance of BQF by increasing its solubility.

To date, the clinical use of the anti-tubercular therapy bedaquiline has been somewhat limited due to safety concerns. Recent investigations determined that modification of the B- and C-ring units of bedaquiline delivered new diarylquinolines (for example TBAJ-587) with potent anti-tubercular activity yet an improved safety profile due to reduced affinity for the hERG channel. Building on our recent discovery that substitution of the quinoline motif (the A-ring subunit) for C5-aryl pyridine groups within bedaquiline analogues led to retention of anti-tubercular activity, we investigated the concurrent modification of A-, B- and C-ring units within bedaquiline variants. This led to the discovery that 4-trifluoromethoxyphenyl and 4-chlorophenyl pyridyl analogues of TBAJ-587 retained relatively potent anti-tubercular activity and for the 4-chlorophenyl derivative in particular, a significant reduction in hERG inhibition relative to bedaquiline was achieved, demonstrating that modifications of the A-, B- and C-ring units within the bedaquiline structure is a viable strategy for the design of effective, yet safer (and less lipophilic) anti-tubercular compounds., (© 2022 Wiley-VCH GmbH.)

The FDA granted expedited approval for Johnson and Johnson's Bedaquiline to treat pulmonary multidrug resistant tuberculosis on 28 December 2012 which is more common in China, Russian Federation and India. Bedaquiline is the first anti-tubercular drug approved by the FDA in the last 40 years, and it has become a cynosure in the circles of synthetic chemists researching new anti-tubercular drugs. Bedaquiline's highly lipophilic nature raises major concerns like suppression of the hERG gene, hepatotoxicity, and phospholipidosis despite its potential antitubercular profile. To address these toxicity concerns, in the present work, we have employed the structural optimization of Bedaquiline using the ADMETopt web server, which optimizes lead with scaffold hopping and ADMET screening. The ADMETopt web server yielded the 476 structures through optimization of three sites in Bedaquiline. Further, we have validated the optimized structures for their activity by performing molecular docking and molecular dynamics (MD) simulations against the mycobacterial ATP synthase enzyme and density functional theory (DFT) study further provides insight into the reactivity of the compounds. After screening and analysis, compound #449 was observed to be the most promising mycobacterial ATP synthase inhibitor with minimal cardiotoxicity, hepatotoxicity and phospholipidosis.

Bedaquiline is a novel adenosine triphosphate synthase inhibitor anti-tuberculosis drug. Bedaquiline belongs to the class of diarylquinolines, which are antituberculosis drugs that are quite different mechanistically from quinolines and flouroquinolines. The fact that relatively similar chemical drugs produce different mechanisms of action is still not widely understood. To enhance discrimination in favor of bedaquiline, a new approach using eight-score principal component analysis (PCA), provided by a ChemGPS-NP model, is proposed. PCA scores were calculated based on 35 + 1 different physicochemical properties and demonstrated clear differences when compared with other quinolines. The ChemGPS-NP model provided an exceptional 100 compounds nearest to bedaquiline from antituberculosis screening sets (with a cumulative Euclidian distance of 196.83), compared with the different 2Dsimilarity provided by Tanimoto methods (extended connective fingerprints and the Molecular ACCess System, showing 30% and 182% increases in cumulative Euclidian distance, respectively). Potentially similar compounds from publicly available antituberculosis compounds and Maybridge sets, based on bedaquiline's eight-dimensional similarity and different filtrations, were identified too.

The COVID-19 outbreak continues to spread worldwide at a rapid rate. Currently, the absence of any effective antiviral treatment is the major concern for the global population. The reports of the occurrence of various point mutations within the important therapeutic target protein of SARS-CoV-2 has elevated the problem. The SARS-CoV-2 main protease (Mpro) is a major therapeutic target for new antiviral designs. In this study, the efficacy of PF-00835231 was investigated (a Mpro inhibitor under clinical trials) against the Mpro and their reported mutants. Various in silico approaches were used to investigate and compare the efficacy of PF-00835231 and five drugs previously documented to inhibit the Mpro. Our study shows that PF-00835231 is not only effective against the wild type but demonstrates a high affinity against the studied mutants as well.

Pharmacokinetic (PK) profiles of a range of bedaquiline (BDQ) long-acting injectable (LAI) microsuspensions in rats after parenteral ( i.e. , intramuscular and subcutaneous) administration were correlated with the in vitro intrinsic dissolution rate (IDR) and thermodynamic solubility of BDQ in media varying in surfactant type and concentration to better understand the impact of different nonionic surfactants on the in vivo performance of BDQ LAI microsuspensions. All LAI formulations had a similar particle size distribution. The investigated surfactants were d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS), poloxamer 338, and poloxamer 188. Furthermore, the relevance of medium complexity by using a biorelevant setup to perform in vitro measurements was assessed by comparing IDR and thermodynamic solubility results obtained in biorelevant media and formulation vehicle containing different surfactants in varying concentrations. In the presence of a surfactant, both media could be applied to obtain in vivo representative dissolution and solubility data because the difference between the biorelevant medium and formulation vehicle was predominantly nonsignificant. Therefore, a more simplistic medium in the presence of a surfactant was preferred to obtain in vitro measurements to predict the in vivo PK performance of LAI aqueous suspensions. The type of surfactant influenced the PK profiles of BDQ microsuspensions in rats, which could be the result of a surfactant effect on the IDR and/or thermodynamic solubility of BDQ. Overall, two surfactant groups could be differentiated: TPGS and poloxamers. Most differences between the PK profiles ( i.e. , maximum concentration observed, time of maximum concentration observed, and area under the curve) were observed during the first 21 days postdose, the time period during which particles in the aqueous suspension are expected to dissolve.

Introduction: Tuberculosis is a life-threatening disease, and the drugs discovered during the era of 1950 and 1970 are found to be inefficient due to emergent MDR and XDR-TB. Tuberculosis is difficult to treat due to the development of antibiotic resistance. ATP synthase consists of two units, F1 and F0 units. These are present in the cytoplasm and membrane of mitochondria, respectively. F1 unit comprises of a, b, and c subunit while F0 subunit has α, β, γ, δ, ε subunits. Bedaquiline was the first approved ATP synthase inhibitor in 2012 by USFDA., Methods: Recent literature from 2005-2020 were collected using Pubmed with the keywords ATP synthase inhibitor, bedaquiline derivatives, tuberculosis. The work describing detailed analyses of bedaquiline (BDQ) was included in the current work, and others were excluded., Results: ATP production occurs via the ATP synthase enzyme, leading to the growth and multiplication of mycobacteria. BDQ inhibits the mycobacterium ATP synthase enzyme, a heteropolymeric complex consisting of two subunits, but it does not interfere with mammalian ATP synthase. Bedaquiline (BDQ) has become a drug of choice in treating MDR-TB and helps in reducing the treatment span. Recently observed triple mutation as wtLeu59 A →mtVal59 A ; wtIle66 A →mtMet66 A and wtGlu61 B →mtAsp61 B of ATP synthase led to decrease BDQ binding affinity; thus, researchers are putting efforts for its newer derivative discovery., Conclusion: ATP synthase inhibitor could be an alternative approach for better treatment of tuberculosis. Herein we discussed the recent advancements in the development of newer analogues of BDQ with its future perspectives., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Tuberculosis-the world's leading cause of death by infectious disease-is increasingly resistant to current first-line antibiotics 1 . The bacterium Mycobacterium tuberculosis (which causes tuberculosis) can survive low-energy conditions, allowing infections to remain dormant and decreasing their susceptibility to many antibiotics 2 . Bedaquiline was developed in 2005 from a lead compound identified in a phenotypic screen against Mycobacterium smegmatis 3 . This drug can sterilize even latent M. tuberculosis infections 4 and has become a cornerstone of treatment for multidrug-resistant and extensively drug-resistant tuberculosis 1,5,6 . Bedaquiline targets the mycobacterial ATP synthase 3 , which is an essential enzyme in the obligate aerobic Mycobacterium genus 3,7 , but how it binds the intact enzyme is unknown. Here we determined cryo-electron microscopy structures of M. smegmatis ATP synthase alone and in complex with bedaquiline. The drug-free structure suggests that hook-like extensions from the α-subunits prevent the enzyme from running in reverse, inhibiting ATP hydrolysis and preserving energy in hypoxic conditions. Bedaquiline binding induces large conformational changes in the ATP synthase, creating tight binding pockets at the interface of subunits a and c that explain the potency of this drug as an antibiotic for tuberculosis.

Aim: The identification of drugs for the coronavirus disease-19 pandemic remains urgent. In this manner, drug repurposing is a suitable strategy, saving resources and time normally spent during regular drug discovery frameworks. Essential for viral replication, the main protease has been explored as a promising target for the drug discovery process. Materials & methods: Our virtual screening pipeline relies on the known 3D properties of noncovalent ligands and features of crystalized complexes, applying consensus analyses in each step. Results: Two oral (bedaquiline and glibenclamide) and one buccal drug (miconazole) presented 3D similarity to known ligands, reasonable predicted binding modes and micromolar predicted binding affinity values. Conclusion: We identified three approved drugs as promising inhibitors of the main viral protease and suggested design insights for future studies for development of novel selective inhibitors.

Bedaquiline (BDQ, Sirturo) has been approved to treat multidrug resistant forms of Mycobacterium tuberculosis. Prior studies suggested that BDQ was a selective inhibitor of the ATP synthase from M. tuberculosis. However, Sirturo treatment leads to an increased risk of cardiac arrhythmias and death, raising the concern that this adverse effect results from inhibition at a secondary site. Here we show that BDQ is a potent inhibitor of the yeast and human mitochondrial ATP synthases. Single-particle cryo-EM reveals that the site of BDQ inhibition partially overlaps with that of the inhibitor oligomycin. Molecular dynamics simulations indicate that the binding mode of BDQ to this site is similar to that previously seen for a mycobacterial enzyme, explaining the observed lack of selectivity. We propose that derivatives of BDQ ought to be made to increase its specificity toward the mycobacterial enzyme and thereby reduce the side effects for patients that are treated with Sirturo.

Bedaquiline (BDQ) has demonstrated formidable bactericidal activity towards Mycobacterium tuberculosis (Mtb) in the treatment of multi-drug resistant (MDR) and extensively drug resistant (XDR) tuberculosis (TB). BDQ elicits its therapeutic function by halting the ionic shuttle of Mtb via mycobacterial F 1 F 0 ATP-synthase blockade. However, triple mutations (L59 V, E61D and I66 M) at the ligand-binding cavity characterize emerging BDQ-resistant strains thereby restraining the potentials embedded in this anti-microbial compound, particularly in MDR/XDR-TB therapy. In this report, the effects of these triple mutations on BDQ-Mtb F 1 F 0 ATP-synthase binding were investigated using molecular dynamics, free energy binding and residue interaction network (RIN) analyses. The highlight of our findings is the drastic reduction in BDQ binding affinity (ΔG) in the triple mutant protein, which was caused by a systemic loss in high-affinity interactions primarily mediated by L59, E61 and I66. While wildtype L59 and I66 formed pi-alkyl interactions with BDQ at the F 1 F 0 ATP-synthase binding site, E61 elicited conventional (O--HO) bond. Upon transition, V59 and I66 were devoid of interactions with BDQ while D61 existed in a weaker non-conventional (C--HO) bond. Likewise, these mutations distorted the binding site and overall structural architecture of F 1 F 0 ATP-synthase in the presence of BDQ as revealed by the RIN and conformational analyses. Insights from this study could serve as a starting point for the structure-based design of novel inhibitors that could overcome mutational setbacks posed by BDQ-resistant strains in MDR/XDR-TB treatment., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Bedaquiline is a novel drug approved in 2012 by the FDA for treatment of drug-resistant tuberculosis (TB). Although it shows high efficacy towards drug-resistant forms of TB, its use has been limited by the potential for significant side effects. In particular, bedaquiline is a very lipophilic compound with an associated long terminal half-life and shows potent inhibition of the cardiac potassium hERG channel, resulting in QTc interval prolongation in humans that may result in cardiac arrhythmia. To address these issues, we carried out a drug discovery programme to develop an improved second generation analogue of bedaquiline. From this medicinal chemistry program, a candidate (TBAJ-876) has been selected to undergo further preclinical evaluation. During this evaluation, three major metabolites arising from TBAJ-876 were observed in several preclinical animal models. We report here our synthetic efforts to unequivocally structurally characterize these three metabolites through their independent directed synthesis.

Analogues of the anti-tuberculosis drug bedaquiline, bearing a 3,5-dimethoxy-4-pyridyl C-unit, retain high anti-bacterial potency yet exert less inhibition of the hERG potassium channel, in vitro, than the parent compound. Two of these analogues (TBAJ-587 and TBAJ-876) are now in preclinical development. The present study further explores structure-activity relationships across a range of related 3,5-disubstituted-4-pyridyl C-unit bedaquiline analogues of greatly varying lipophilicity (clogP from 8.16 to 1.89). This broader class shows similar properties to the 3,5-dimethoxy-4-pyridyl series, being substantially more potent in vitro and equally active in an in vivo (mouse) model than bedaquiline, while retaining a lower cardiovascular risk profile through greatly attenuated hERG inhibition., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Background: Bedaquiline is a novel anti-tuberculosis drug that inhibits Mycobacterial ATP synthase. However, studies have found that bedaquiline has serious side effects due to high lipophilicity. Recently, the complete structure of ATP synthase was first reported in the Journal of Science., Objective: The study aimed to design, synthesise and carry out biological evaluation of antituberculosis agents based on the structure of bedaquiline., Methods: The mode of action of bedaquiline and ATP synthase was determined by molecular docking, and a series of low lipophilic bedaquiline derivatives were synthesized. The inhibitory activities of bedaquiline derivatives towards Mycobacterium phlei 1180 and Mycobacterium tuberculosis H37Rv were evaluated in vitro. A docking study was carried out to elucidate the structureactivity relationship of the obtained compounds. The predicted ADMET properties of the synthesized compounds were also analyzed., Results: The compounds 5c3, 6a1, and 6d3 showed good inhibitory activities (MIC=15.62 ug.mL-1). At the same time, the compounds 5c3, 6a1, and 6d3 also showed good drug-like properties through molecular docking and ADMET properties prediction., Conclusion: The results of in vitro anti-tuberculosis activity assays, docking studies and ADMET predictions indicate that the synthesized compounds have potential antifungal activity, with compounds 6a1 being further optimized and developed as lead compounds., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

In this study, amino-oxy-diarylquinolines were designed using structure-guided molecular hybridization strategy and fusing of the pharmacophore templates of nevirapine (NVP), efavirenz (EFV), etravirine (ETV, TMC125) and rilpivirine (RPV, TMC278). The anti-HIV-1 reverse transcriptase (RT) activity was evaluated using standard ELISA method, and the cytotoxic activity was performed using MTT and XTT assays. The primary bioassay results indicated that 2-amino-4-oxy-diarylquinolines possess moderate inhibitory properties against HIV-1 RT. Molecular docking results showed that 2-amino-4-oxy-diarylquinolines 8(A-D): interacted with the Lys101 and His235 residue though hydrogen bonding and interacted with Tyr318 residue though π-π stacking in HIV-1 RT. Furthermore, 8A: and 8D: were the most potent anti-HIV agents among the designed and synthesized compounds, and their inhibition rates were 34.0% and 39.7% at 1 µM concentration. Interestingly, 8A: was highly cytotoxicity against MOLT-3 (acute lymphoblastic leukemia), with an IC 50 of 4.63±0.62 µg/mL, which was similar with that in EFV and TMC278 (IC 50 7.76±0.37 and 1.57±0.20 µg/ml, respectively). Therefore, these analogs of the synthesized compounds can serve as excellent bases for the development of new anti-HIV-1 agents in the near future., Competing Interests: The authors have declared no conflict of interest., (© Georg Thieme Verlag KG Stuttgart · New York.)

Tuberculosis (TB) has gained attention over the past few decades by becoming one of the top ten leading causes of death worldwide. This infectious disease of the lungs is orally treated with a medicinal armamentarium. However, this route of administration passes through the body's first-pass metabolism which reduces the drugs' bioavailability and toxicates the liver and kidneys. Inhalation therapy represents an alternative to the oral route, but low deposition efficiencies of delivery devices such as nebulizers and dry powder inhalers render it challenging as a favorable therapy. It was hypothesized that by encapsulating two potent TB-agents, i.e. Q203 and bedaquiline, that inhibit the oxidative phosphorylation of the bacteria together with a magnetic targeting component, superparamagnetic iron oxides, into a poly (D, L-lactide-co-glycolide) (PDLG) carrier using a single emulsion technique, the treatment of TB can be a better therapeutic alternative. This simple fabrication method achieved a homogenous distribution of 500 nm particles with a magnetic saturation of 28 emu/g. Such particles were shown to be magnetically susceptible in an in-vitro assessment, viable against A549 epithelial cells, and were able to reduce two log bacteria counts of the Bacillus Calmette-Guerin (BCG) organism. Furthermore, through the use of an external magnet, our in-silico Computational Fluid Dynamics (CFD) simulations support the notion of yielding 100% deposition in the deep lungs. Our proposed inhalation therapy circumvents challenges related to oral and respiratory treatments and embodies a highly favorable new treatment regime.

Drug-resistant tuberculosis (DR-TB) is an emerging health problem, challenging the effective control of global TB. Current treatment of DR-TB includes administration of multiple anti-TB drugs via oral and parenteral routes for a duration of 20-28 months. High systemic exposure, side effects and lengthy treatment time are problems affecting current treatment. The success rate of current lengthy treatment regimens is generally <50%. Bedaquiline, a new anti-TB drug is synergistic with pyrazinamide and in combination with moxifloxacin accelerates sputum-culture conversion. Therefore, a triple combination of these drugs may have the potential to shorten the treatment time and improve treatment success. Additionally, inhalation of these drugs in combination may be advantageous due to the direct delivery to the lungs, possibly reducing systemic exposure. This study aimed to develop an inhalable triple combination powder of bedaquiline, moxifloxacin and pyrazinamide and study their physicochemical properties and safety. An inhalable (aerodynamic diameter: ≤2.4 µm) triple combination powder of bedaquiline, moxifloxacin and pyrazinamide with 20% w/w of L-leucine was prepared using a Buchi Mini Spray-Dryer. Combination powder consisted of spherical and porous particles. In vitro aerosolization (fine particle fraction, FPF) determined using a next generation impactor (NGI) showed improved FPF as a combination powder (>75.0%) when compared to single drug-only formulations (<45.0%). The powder was non-toxic to A549 and Calu-3 cells up to 100 µg/mL and stable at 30 ± 2% RH and ambient room temperature during one-month storage. This is the first study reporting the development of inhalable triple combination powder of bedaquiline, moxifloxacin and pyrazinamide with high aerosolization efficiency. The improved aerosolization may help to deliver a high dose of these drugs to treat drug-resistant tuberculosis., (Copyright © 2019 Elsevier B.V. All rights reserved.)

One-third of the world's population carries Mycobacterium tuberculosis ( Mtb ), the infectious agent that causes tuberculosis (TB), and every 17 s someone dies of TB. After infection, Mtb can live dormant for decades in a granuloma structure arising from the host immune response, and cholesterol is important for this persistence of Mtb . Current treatments require long-duration drug regimens with many associated toxicities, which are compounded by the high doses required. We phenotypically screened 35 6-azasteroid analogues against Mtb and found that, at low micromolar concentrations, a subset of the analogues sensitized Mtb to multiple TB drugs. Two analogues were selected for further study to characterize the bactericidal activity of bedaquiline and isoniazid under normoxic and low-oxygen conditions. These two 6-azasteroids showed strong synergy with bedaquiline (fractional inhibitory concentration index = 0.21, bedaquiline minimal inhibitory concentration = 16 nM at 1 μM 6-azasteroid). The rate at which spontaneous resistance to one of the 6-azasteroids arose in the presence of bedaquiline was approximately 10 -9 , and the 6-azasteroid-resistant mutants retained their isoniazid and bedaquiline sensitivity. Genes in the cholesterol-regulated Mce3R regulon were required for 6-azasteroid activity, whereas genes in the cholesterol catabolism pathway were not. Expression of a subset of Mce3R genes was down-regulated upon 6-azasteroid treatment. The Mce3R regulon is implicated in stress resistance and is absent in saprophytic mycobacteria. This regulon encodes a cholesterol-regulated stress-resistance pathway that we conclude is important for pathogenesis and contributes to drug tolerance, and this pathway is vulnerable to small-molecule targeting in live mycobacteria.

Bedaquiline was approved by USFDA in 2012 for pulmonary MDR-TB. The IC 50 value of bedaquiline was reported to be remarkably low (25 nM), effectively inhibiting mycobacterial ATP synthase. In addition to these obvious assets of bedaquiline, the potential disadvantages of bedaquiline include inhibition of the hERG (human Ether-à-go-related gene; KCNH 2 ) potassium channel (concurrent risk of cardiac toxicity), hepatic toxicity and possibly phospholipidosis. The current review focuses primarily on the structural part of bedaquiline for the activity-toxicity optimization. This critical analysis of the structure of bedaquiline will help medicinal chemists to synthesize the better modified analouge of bedaquiline with reduced cardiotoxicity, hepatotoxicity potential and improved pharmacokinetics., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Mycobacterium tuberculosis infection results in more than two million deaths per year and is the leading cause of mortality in people infected with HIV. A new structural class of antimycobacterials, the diarylquinolines, has been synthesized and is being highly effective against both M. tuberculosis and multidrug-resistant tuberculosis. As diarylquinolines are biologically active only under their ( R,S) stereoisomeric form, it is essential to differentiate the stereoisomers ( R,S) and ( R,R). To achieve this, tandem mass spectrometry and ion mobility spectrometry-mass spectrometry have been performed with 10 diarylquinoline diastereomers couples. In this study, we investigated cationization with alkali metal cations and several ion mobility drift gases in order to obtain diastereomer differentiations. We have shown that diastereomers of the diarylquinolines family can be differentiated separately by tandem mass spectrometry and in mixture by ion mobility spectrometry-mass spectrometry. However, although the structure of each diastereomer is close, several behaviors could be observed concerning the cationization and the ion mobility spectrometry separation. The ion mobility spectrometry isomer separation efficiency is not easily predictable; it was however observed for all diastereomeric couples with a significant improvement of separation using alkali adducts compared to protonated molecules. With the use of drift gas with higher polarizability only an improvement of separation was obtained in a few cases. Finally, a good correlation of the experimental collision cross section (relative to three-dimensional structure of ions) and the theoretical collision cross section has been shown.

In the present work, the question how to obtain high-quality laser diffraction (LD) results is discussed by investigating various hurdles that can be encountered during particle size measurements in wet dispersions and the associated data interpretation. Following this an effective troubleshooting is discussed based on theoretical insight into the LD measurement. As an important element in the Mie theory, the refractive indices of the model compounds, bedaquiline and cinnarizine, were quantified using the LD software, the Becke line technique, and the single solvent technique, as described by Saveyn et al. [Saveyn H, et al. Part Part Syst Char. 2001;19:426-432]. The influence of parameters such as obscuration level, background quality, and fitting of data were investigated and a summative flow chart has been provided. Through this analysis the present work emphasizes the need for a systematic approach when conducting LD measurements, including standard performance of an obscuration titration and an extended method optimization, to reach high-quality LD results., (Copyright © 2019 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.)

A continuous effort has been given to find out a new drug that is effective against tuberculosis (TB) from both susceptible and resistant strains of Mycobacterium tuberculosis. Bedaquiline represents a recently approved anti-TB drug, which has a unique mechanism of action to fight against multi drug resistance (MDR). Some severe side effects and drug-drug interactions are associated with the treatment of bedaquiline. Moreover, World Health Organisation (WHO) has also been provided guidelines in the year of 2013 for the use of bedaquiline and encourages additional investigation into it. Hence, the pharmacokinetics of bedaquiline upon coadministration with the drug has to be explored in the preclinical model and for which a liquid chromatography tandem mass spectrometry (LC-MS/MS) based bioanalytical method for quantitation of bedaquiline will be useful. A simple, sensitive and rapid LC-MS/MS method was developed, validated and successfully applied to drug interactions of bedaquiline upon coadministration with cytochrome P450 3A4 (CYP3A4) inducers/inhibitors orally in Wistar rats. Results reveal that ciprofloxacin and fluconazole have marked effect to hinder the pharmacokinetics of bedaquiline but isoniazid, verapamil and carbamazepine have no significant effect on bedaquiline pharmacokinetics. Overall, this new bioanalytical method for estimation of bedaquiline in rat plasma was found to be helpful to assess the pharmacokinetics of bedaquiline and very much useful for evaluation of preclinical drug-drug interaction before considering costly and perilous clinical exploration., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Bedaquiline is a new drug of the diarylquinoline class that has proven to be clinically effective against drug-resistant tuberculosis, but has a cardiac liability (prolongation of the QT interval) due to its potent inhibition of the cardiac potassium channel protein hERG. Bedaquiline is highly lipophilic and has an extremely long terminal half-life, so has the potential for more-than-desired accumulation in tissues during the relatively long treatment durations required to cure TB. The present work is part of a program that seeks to identify a diarylquinoline that is as potent as bedaquiline against Mycobacterium tuberculosis, with lower lipophilicity, higher clearance, and lower risk for QT prolongation. Previous work led to the identification of compounds with greatly-reduced lipophilicity compounds that retain good anti-tubercular activity in vitro and in mouse models of TB, but has not addressed the hERG blockade. We now present compounds where the C-unit naphthalene is replaced by a 3,5-dialkoxy-4-pyridyl, demonstrate more potent in vitro and in vivo anti-tubercular activity, with greatly attenuated hERG blockade. Two examples of this series are in preclinical development., (Copyright © 2019 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The ATP-synthase inhibitor bedaquiline is effective against drug-resistant tuberculosis but is extremely lipophilic (clogP 7.25) with a very long plasma half-life. Additionally, inhibition of potassium current through the cardiac hERG channel by bedaquiline, is associated with prolongation of the QT interval, necessitating cardiovascular monitoring. Analogues were prepared where the naphthalene C-unit was replaced with substituted pyridines to produce compounds with reduced lipophilicity, anticipating a reduction in half-life. While there was a direct correlation between in vitro inhibitory activity against M. tuberculosis (MIC 90 ) and compound lipophilicity, potency only fell off sharply below a clogP of about 4.0, providing a useful lower bound for analogue design. The bulk of the compounds remained potent inhibitors of the hERG potassium channel, with notable exceptions where IC 50 values were at least 5-fold higher than that of bedaquiline. Many of the compounds had desirably higher rates of clearance than bedaquiline, but this was associated with lower plasma exposures in mice, and similar or higher MICs resulted in lower AUC/MIC ratios than bedaquiline for most compounds. The two compounds with lower potency against hERG exhibited similar clearance to bedaquiline and excellent efficacy in vivo, suggesting further exploration of C-ring pyridyls is worthwhile., (Copyright © 2019 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The coating of polypeptidic micelles with sodium alginate is described as a strategy to improve the stability of micelles for drug delivery. Bedaquiline, approved in 2012 for the treatment of multidrug resistant tuberculosis, has been used as an example of hydrophobic drug to study the loading efficiency, the release of the encapsulated drug in different media, and the in vitro antimicrobial activity of the system. Alginate coating prevents the burst release of the drug from micelles upon dilution and leads to a sustained release in all tested media. In view of possible oral administration, the alginate coated micelles show better stability in gastric and intestinal simulated media. Notably, the encapsulated bedaquiline shows increased in vitro activity against Mycobacterium tuberculosis compared to free bedaquiline., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The crystal structure of the F 1 -catalytic domain of the adenosine triphosphate (ATP) synthase has been determined from Mycobacterium smegmatis which hydrolyzes ATP very poorly. The structure of the α 3 β 3 -component of the catalytic domain is similar to those in active F 1 -ATPases in Escherichia coli and Geobacillus stearothermophilus However, its ε-subunit differs from those in these two active bacterial F 1 -ATPases as an ATP molecule is not bound to the two α-helices forming its C-terminal domain, probably because they are shorter than those in active enzymes and they lack an amino acid that contributes to the ATP binding site in active enzymes. In E. coli and G. stearothermophilus , the α-helices adopt an "up" state where the α-helices enter the α 3 β 3 -domain and prevent the rotor from turning. The mycobacterial F 1 -ATPase is most similar to the F 1 -ATPase from Caldalkalibacillus thermarum , which also hydrolyzes ATP poorly. The β E -subunits in both enzymes are in the usual "open" conformation but appear to be occupied uniquely by the combination of an adenosine 5'-diphosphate molecule with no magnesium ion plus phosphate. This occupation is consistent with the finding that their rotors have been arrested at the same point in their rotary catalytic cycles. These bound hydrolytic products are probably the basis of the inhibition of ATP hydrolysis. It can be envisaged that specific as yet unidentified small molecules might bind to the F 1 domain in Mycobacterium tuberculosis , prevent ATP synthesis, and inhibit the growth of the pathogen., Competing Interests: The authors declare no conflict of interest.

The high-performance liquid chromatography (HPLC) is a powerful method in the area of stereoisomer separation. In this study, separation of eight bedaquiline analogue diastereomers (compounds 1-8) was first examined on a cellulose tris-(3,5-dichlorophenylcarbamate) chiral stationary phase, ie, Chiralpak IC in the normal phase mode. The influences of organic modifier types, alcohol content, and column temperature on diastereoseparation were evaluated. Under the optimum chromatographic conditions, all the analyte stereoisomers were successfully separated. The experimental results revealed the great influence of analytes' structures on the diastereoseparation with Chiralpak IC. In addition, thermodynamic parameters were calculated by Van't Hoff plots, and correlative chiral recognition mechanisms were discussed further., (© 2018 Wiley Periodicals, Inc.)

The purpose of the present research work was to explore chitosan nanoparticles (NPs) of a novel anti-tubercular drug, bedaquiline (BDQ) in order to reduce dose and side effects associated with oral BDQ formulation. The NPs were fabricated using ionic gelation method and evaluated for particle size, zeta potential, entrapment efficiency and drug loading. Plackett Burman was used as screening design. Two level three-factor factorial design was applied for optimization. Following freeze drying of NPs, the powder obtained was mixed with lactose pre-blend to obtain a respirable powder. In vitro deposition studies were performed using non-viable cascade impactor. In vitro cytotoxicity and in vivo toxicity studies were performed. In vivo pharmacokinetics of NPs formulation was compared with conventional dry powder inhaler (DPI) formulation and oral drug solution. Polymer amount, TPP concentration and probe sonication time were the significant factors. Optimized batch showed particle size of 109.7 ± 9.3 nm with a zeta potential of 36 ± 2.1 mV. In vitro and in vivo toxicity studies unveiled better safety profile of NPs in comparison to conventional DPI and oral solution. Pharmacokinetic studies manifested higher concentration of BDQ in lungs via developed formulation. Therefore, the developed formulation could efficiently deliver BDQ into the lungs., (Copyright © 2018 Elsevier B.V. All rights reserved.)

A procedure is evolved to assess the maximum uncoupling activity of the classical unsubstituted phenolic uncouplers of mitochondrial oxidative phosphorylation (OX PHOS) 2,4-dinitrophenol and 2,6-dinitrophenol. The uncoupler concentrations, C, required for maximum uncoupling efficacy are found to be a strong function of the pH, and a linear relationship of pC with pH is obtained between pH 5 to pH 9. The slopes of the uncoupler concentrations in the aqueous and lipid phases as a function of pH have been estimated. It is shown that the experimental results can be derived from first principles by an enzyme kinetic model for uncoupling that is based on the same equations as formulated for the coupling of ion transport to ATP synthesis in a companion paper after imposition of the special conditions arising from the uncoupling process. The results reveal the catalysis of a reaction that involves both the anionic and protonated forms of the phenolic uncouplers in the vicinity of their binding sites in a non-aqueous region of the cristae membranes of mitochondria. The rate-limiting step in the overall process of uncoupling has been identified based on the uncoupling data. The data cannot be explained by a simple conduction of protons by uncouplers from one bulk aqueous phase to another as postulated by Mitchell's chemiosmotic theory. It is shown that Nath's two-ion theory of energy coupling/uncoupling in ATP synthase is consistent with the results. A molecular mechanism for uncoupling of ATP synthesis by the dinitrophenols is presented and the chief differences between coupling and uncoupling in ATP catalysis are summarized. The pharmacological consequences of our analysis of uncoupling are discussed, with particular reference to the mode of action of the anti-tuberculosis drug bedaquiline that specifically targets the c-subunit of the F 1 F O -ATP synthase and uncouples respiration from ATP synthesis in Mycobacterium tuberculosis. Hence the work is shown to be important both from the point of view of fundamental biology and is also pregnant with possibilities for practical pharmaceutical applications., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Replacing the naphthalene C-unit of the anti-tuberculosis drug bedaquiline with a range of bicyclic heterocycles of widely differing lipophilicity gave analogs with a 4.5-fold range in clogP values. The biological results for these compounds indicate on average a lower clogP limit of about 5.0 in this series for retention of potent inhibitory activity (MIC 90 s) against M.tb in culture. Some of the compounds also showed a significant reduction in inhibition of hERG channel potassium current compared with bedaquiline, but there was no common structural feature that distinguished these., (Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Resistance to non-nucleoside reverse transcriptase inhibitors (NNRTIs) is a leading cause of HIV treatment failure. Often included in antiviral therapy, NNRTIs are chemically diverse compounds that bind an allosteric pocket of enzyme target reverse transcriptase (RT). Several new NNRTIs incorporate flexibility in order to compensate for lost interactions with amino acid conferring mutations in RT. Unfortunately, even successful inhibitors such as diarylpyrimidine (DAPY) inhibitor rilpivirine are affected by mutations in RT that confer resistance. In order to aid drug design efforts, it would be efficient and cost effective to pre-evaluate NNRTI compounds in development using a structure-based computational approach. As proof of concept, we applied a residue scan and molecular dynamics strategy using RT crystal structures to predict mutations that confer resistance to DAPYs rilpivirine, etravirine, and investigational microbicide dapivirine. Our predictive values, changes in affinity and stability, are correlative with fold-resistance data for several RT mutants. Consistent with previous studies, mutation K101P is predicted to confer high-level resistance to DAPYs. These findings were further validated using structural analysis, molecular dynamics, and an enzymatic reverse transcription assay. Our results confirm that changes in affinity and stability for mutant complexes are predictive parameters of resistance as validated by experimental and clinical data. In future work, we believe that this computational approach may be useful to predict resistance mutations for inhibitors in development., (Published by Elsevier Inc.)

Analogues of bedaquiline where the phenyl B-unit was replaced with monocyclic heterocycles of widely differing lipophilicity (thiophenes, furans, pyridines) were synthesised and evaluated. While there was an expected broad positive correlation between lipophilicity and anti-TB activity, the 4-pyridyl derivatives appeared to have an additional contribution to antibacterial potency. The majority of the compounds were (desirably) more polar and had higher rates of clearance than bedaquiline, and showed acceptable oral bioavailability, but there was only limited (and unpredictable) improvement in their hERG liability., (Copyright © 2017. Published by Elsevier Ltd.)

Bedaquiline (BDQ) is an antibiotic to treat pulmonary multidrug-resistant tuberculosis (MDR-TB). Studies up to 39 weeks were conducted orally in dogs to assess the toxicity and pharmacokinetics of BDQ and its N-desmethyl metabolite (D-BDQ). Phospholipidosis (PLD) seen in the monocytic phagocytic system was considered an adaptive change. Skeletal muscle, heart, stomach, liver, and pancreas toxicities with D-BDQ as the main contributor were associated with a less-than-dose-proportional increase in plasma exposure and an overproportional tissue uptake of BDQ and D-BDQ at high-dose levels. Tissue concentrations of BDQ and D-BDQ slowly decreased after lowering the dose, contributing to the recovery of the pathological findings. Treatment was better tolerated at mid-dose levels, characterized by a dose-proportional increase in plasma and tissue exposures. Treatment at a low dose, reaching exposures approximating therapeutic exposures, was without adverse effects and not associated with PLD. There was no evidence of delayed toxicities after treatment cessation. Intermittent dosing was better tolerated at high doses. Since MDR-TB patients are dosed within the linear plasma exposure range and plasma levels of BDQ and D-BDQ are similar or lower than in dogs, PLD and adverse findings related to tissue accumulation that occurred at high doses in dogs are unlikely to occur in humans.

Drug-resistant (DR)-TB is the major challenge confronting the global TB control programme, necessitating treatment with second-line anti-TB drugs, often with limited therapeutic efficacy. This scenario has resulted in the inclusion of Group 5 antibiotics in various therapeutic regimens, two of which promise to impact significantly on the outcome of the therapy of DR-TB. These are the 're-purposed' riminophenazine, clofazimine, and the recently approved diarylquinoline, bedaquiline. Although they differ structurally, both of these lipophilic agents possess cationic amphiphilic properties that enable them to target and inactivate essential ion transporters in the outer membrane of Mycobacterium tuberculosis. In the case of bedaquiline, the primary target is the key respiratory chain enzyme F 1 /F 0 -ATPase, whereas clofazimine is less selective, apparently inhibiting several targets, which may underpin the extremely low level of resistance to this agent. This review is focused on similarities and differences between clofazimine and bedaquiline, specifically in respect of molecular mechanisms of antimycobacterial action, targeting of quiescent and metabolically active organisms, therapeutic efficacy in the clinical setting of DR-TB, resistance mechanisms, pharmacodynamics, pharmacokinetics and adverse events., (© The Author 2016. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)

Bedaquiline (BDQ) is a novel and highly potent last-line antituberculosis drug that was approved by the US FDA in 2013. Owing to its stereo-structural complexity, chemical synthesis and compound optimization are rather difficult and expensive. This study describes the structural simplification of bedaquiline while preserving antitubercular activity. The compound's structure was split into fragments and reassembled in various combinations while replacing the two chiral carbon atoms with an achiral linkage instead. Four series of analogues were designed; these candidates retained their potent antitubercular activity at sub-microgram per mL concentrations against both sensitive and multidrug-resistant (MDR) Mycobacterium tuberculosis strains. Six out of the top nine MIC-ranked candidates were found to inhibit mycobacterial ATP synthesis activity with IC 50 values between 20 and 40 μm, one had IC 50 >66 μm, and two showed no inhibition, despite their antitubercular activity. These results provide a basis for the development of chemically less complex, lower-cost bedaquiline derivatives and describe the identification of two derivatives with antitubercular activity against non-ATP synthase related targets., (© 2016 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.)

Multi-drug resistant tuberculosis (MDR-TB) is of growing global concern and threatens to undermine increasing efforts to control the worldwide spread of tuberculosis (TB). Bedaquiline has recently emerged as a new drug developed to specifically treat MDR-TB. Despite being highly effective as a result of its unique mode of action, bedaquiline has been associated with significant toxicities and as such, safety concerns are limiting its clinical use. In order to access pharmaceutical agents that exhibit an improved safety profile for the treatment of MDR-TB, new synthetic pathways to facilitate the preparation of bedaquiline and analogues thereof have been discovered.

A series of bedaquiline analogs containing H-bond donors were designed as anti-Mycobacterium tuberculosis drugs. A pair of diastereoisomers (R/S- and S/S-isomers) was selected from these designed compounds for synthetic and stereochemical research. The title compounds were synthesized from chiral precursors for the first time and the absolute configurations (ACs) were determined by electronic circular dichroism (ECD) with quantum chemical calculations. Moreover, a single crystal of the S/S compound was obtained for X-ray diffraction analysis, and the crystal structure showed high consistency with the geometry, confirming the reliability of ACs obtained by ECD analyses and theoretical simulation. Furthermore, the effect of stereochemistry on the anti-tuberculosis activity was investigated. The MICs of the R/S- and S/S-isomers against Mycobacterium phlei 1180 are 9.6 and 32.1 μg·mL(-1), respectively. Finally, molecular docking was carried out to evaluate the inhibitory nature and binding mode differences between diastereoisomers.

Bedaquiline is the first FDA-approved new chemical entity to fight multidrug-resistant tuberculosis in the last forty years. Our group replaced the quinoline ring with a naphthalene ring, leading to a new type of triarylbutanol skeleton. An asymmetric synthetic route was established for our bedaquiline analogues, and the goal of assigning their absolute configurations was achieved by comparison of experimental and calculated electronic circular dichroism spectra, and was confirmed by the combined use of circular dichroism and NMR spectroscopy.

Two new NHC adducts of cyclopalladated ferrocenylpyrazine complexes 1-2 have been prepared and characterized. An efficient NHC-modulated Pd/Cu cocatalyzed three-component coupling reaction for the synthesis of 2,6-diarylquinolines from aminobenzyl alcohols, aryl ketones, and arylboronic acids in air is described. The reaction involves oxidation, cyclization and Suzuki reactions. The luminescence of the resulting arylquinolines 3-30 was also investigated.

Tuberculosis is a major global health problem. In the middle of the last century several laboratories identified, developed and synthesized several substances which were active against Mycobacterium tuberculosis, the causative agent of the disease. In the 1980s the standard oral treatment regimen was introduced with isoniazid, rifampicin, pyrazinamide, and ethambutol. In combination with the DOTS strategy it was possible treat TB within 6-8 months. But with the emergence of drug resistant strains, the formerly successful regiment became ineffective for MDR and XDR TB patients. Even more alarming, the rapidly increasing HIV epidemic also increases the number of HIV-related TB. Facing these facts, it became evident that novel strategies and antibiotics were needed to treat the new forms of TB. But over the last 60 years no novel TB drug was developed or even in the drug pipeline. But during the last ten years several novel substances have been developed to combat the deadly disease. For the first time in decades the TB drug pipeline is filled again with several promising compounds and many of them have reached Phase II and Phase III clinical trials. Several laboratories and companies all over the world currently are developing and evaluating these substances. This review presents novel substances, which were for the first time exclusively developed for TB such as bedaquilines, nitroimidazoles and the diamine SQ109. We also summarize the present knowledge about enzymes and biosynthesis pathways which offer potential targets for drug discovery against M. tuberculosis.

Each year, a huge number of new cases accounts of TB with added problems due to multidrug resistant TB varieties. Globally, TB is one of the top causes of loss of life among people living with HIV who are more likely than others to get TB infection. Current TB treatment includes long term administration of cocktail of drugs; hence, the development of an alternative armamentarium against TB is the primary requirement. In fact, new drugs with novel activity against mycobacteria are of significant importance in order to combat existing levels of resistance. The present report covers the discovery of a diarylquinoline TB drug, bedaquiline, its antituberculosis effects and mode of action. Clinical studies conducted on bedaquiline which brought it to the accelerated FDA acceptance have been described. This report is of great attention for therapeutic apothecaries working in TB medication growth in terms of creating further diarylquinoline applicants with a wide variety of antimycobacterial results.

TB still represents a serious public health problem. The latest reports estimate an incidence of 8.7 million cases in 2011 and 1.4 million deaths. Drug resistance contributed an estimated 630,000 cases of multidrug-resistant TB, making control of the disease harder. Recent reports show cases of TB that were almost resistant to all available antibiotics. Therefore, there is an urgent need to develop new anti-TB drugs with the potential of reducing the current length of treatment. Bedaquiline, formerly TMC207, is a new diarylquinoline antibiotic with specific activity against Mycobacterium tuberculosis and several nontuberculous mycobacteria. It acts by inhibiting ATP synthase, interfering with the energy generation needed by the bacterial cell. Based on clinical evaluations for safety, tolerability and efficacy, bedaquiline has recently received accelerated approval for the treatment of pulmonary multidrug-resistant TB in adults. This article will review the main aspects related to the chemistry, microbiology, pharmacology, efficacy and tolerability of bedaquiline.

Tuberculosis (TB) is a serious public health issue, particularly in underdeveloped and developing countries. Furthermore the first-line anti-TB treatments were established over 40 years ago, multidrug-resistant Mycobacterium tuberculosis strains have been developed and the risk of coinfection with AIDS virus has highlighted this disease as a global emergency. The urgent need for more effective treatments against multidrug-resistant strains compatible with anti-AIDS drugs has prompted industries, governments and non-governmental agencies to pursue new drugs. In this study, we update the portfolio listed at Stop TB Partnership, present the biological activities as well as structure-activity relationship for these drugs and thoroughly discuss the synthetic methodologies used to produce these drugs.