scholarly journals In vitro and in vivo efficacy, toxicity, bio-distribution and resistance selection of a novel antibacterial drug candidate

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Jlenia Brunetti ◽  
Chiara Falciani ◽  
Giulia Roscia ◽  
Simona Pollini ◽  
Stefano Bindi ◽  
...  
Keyword(s):  
Drug Candidate ◽  
Antibacterial Drug ◽  
In Vivo Efficacy ◽  
Resistance Selection ◽  
Selection Of

scholarly journals In-Vitro Selection of Ceftazidime/Avibactam Resistance in OXA-48-Like-Expressing Klebsiella pneumoniae: In-Vitro and In-Vivo Fitness, Genetic Basis and Activities of β-Lactam Plus Novel β-Lactamase Inhibitor or β-Lactam Enhancer Combinations

Antibiotics ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1318
Author(s):  
Snehal Palwe ◽  
Yamuna Devi Bakthavatchalam ◽  
Kshama Khobragadea ◽  
Arun S. Kharat ◽  
Kamini Walia ◽  
...  
Keyword(s):  
In Vitro Selection ◽  
Whole Genome Sequence ◽  
Serial Transfer ◽  
Resistance Selection ◽  
Clinical Resistance ◽  
Growth Properties ◽  
Outer Membrane Permeability ◽  
Selection Of

Ceftazidime/avibactam uniquely demonstrates activity against both KPC and OXA-48-like carbapenemase-expressing Enterobacterales. Clinical resistance to ceftazidime/avibactam in KPC-producers was foreseen in in-vitro resistance studies. Herein, we assessed the resistance selection propensity of ceftazidime/avibactam in K. pneumoniae expressing OXA-48-like β-lactamases (n = 10), employing serial transfer approach. Ceftazidime/avibactam MICs (0.25–4 mg/L) increased to 16–256 mg/L after 15 daily-sequential transfers. The whole genome sequence analysis of terminal mutants showed modifications in proteins linked to efflux (AcrB/AcrD/EmrA/Mdt), outer membrane permeability (OmpK36) and/or stress response pathways (CpxA/EnvZ/RpoE). In-vitro growth properties of all the ceftazidime/avibactam-selected mutants were comparable to their respective parents and they retained the ability to cause pulmonary infection in neutropenic mice. Against these mutants, we explored the activities of various combinations of β-lactams (ceftazidime or cefepime) with structurally diverse β-lactamase inhibitors or a β-lactam enhancer, zidebactam. Zidebactam, in combination with either cefepime or ceftazidime, overcame ceftazidime/avibactam resistance (MIC range 0.5–8 mg/L), while cefepime/avibactam was the second best (MIC: 0.5–16 mg/L) in yielding lower MICs. The present work revealed the possibility of ceftazidime/avibactam resistance in OXA-48-like K. pneumoniae through mutations in proteins involved in efflux and/or porins without concomitant fitness cost mandating astute monitoring of ceftazidime/avibactam resistance among OXA-48 genotypes.

Human Hepatic Cell Cultures: In Vitro and In Vivo Drug Metabolism

2003 ◽  
Vol 31 (3) ◽  
pp. 257-265 ◽  
Author(s):  
María José Gómez-Lechón ◽  
Teresa Donato ◽  
Xavier Ponsoda ◽  
José V. Castell
Keyword(s):  
Drug Metabolism ◽  
Metabolic Profile ◽  
Animal Species ◽  
In Vitro Models ◽  
Human Hepatocytes ◽  
Cellular Systems ◽  
Drug Candidate ◽  
Selection Of

Drug metabolism is the major determinant of drug clearance, and the factor most frequently responsible for inter-individual differences in drug pharmacokinetics. The expression of drug metabolising enzymes shows significant interspecies differences, and variability among human individuals (polymorphic or inducible enzymes) makes the accurate prediction of the metabolism of a new compound in humans difficult. Several key issues need to be addressed at the early stages of drug development to improve drug candidate selection: a) how fast the compound will be metabolised; b) what metabolites will be formed (metabolic profile); c) which enzymes are involved and to what extent; and d) whether drug metabolism will be affected directly (drug-drug interactions) or indirectly (enzyme induction) by the administered compound. Drug metabolism studies are routinely performed in laboratory animals, but they are not sufficiently accurate to predict the metabolic profiles of drugs in humans. Many of these issues can now be addressed by the use of relevant human in vitro models, which speed up the selection of new candidate drugs. Human hepatocytes are the closest in vitro model to the human liver, and they are the only model which can produce a metabolic profile of a drug which is very similar to that found in vivo. However, the use of human hepatocytes is restricted, because limited access to suitable tissue samples prevents their use in high throughput screening systems. The pharmaceutical industry has made great efforts to develop fast and reliable in vitro models to overcome these drawbacks. Comparative studies on liver microsomes and cells from animal species, including humans, are very useful for demonstrating species differences in the metabolic profile of given drug candidates, and are of great value in the judicious and justifiable selection of animal species for later pharmacokinetic and toxicological studies. Cytochrome P450 (CYP)-engineered cells (or microsomes from CYP-engineered cells, for example, Supersomes™) have made the identification of the CYPs involved in the metabolism of a drug candidate more straightforward and much easier. However, the screening of compounds acting as potential CYP inducers can only be conducted in cellular systems fully capable of transcribing and translating CYP genes.

scholarly journals Y-688, a New Quinolone Active against Quinolone-Resistant Staphylococcus aureus: Lack of In Vivo Efficacy in Experimental Endocarditis

1998 ◽  
Vol 42 (8) ◽  
pp. 1889-1894 ◽  
Author(s):  
J. M. Entenza ◽  
O. Marchetti ◽  
M. P. Glauser ◽  
P. Moreillon
Keyword(s):  
Staphylococcus Aureus ◽  
In Vivo Efficacy ◽  
Methicillin Resistant ◽  
Bacterial Counts ◽  
Resistance Selection ◽  
New Quinolones ◽  
Increased Activity ◽  
Trough Levels

ABSTRACT Y-688 is a new fluoroquinolone with increased activity against ciprofloxacin-resistant staphylococci. The MICs of Y-688 and other quinolones were determined for 58 isolates of ciprofloxacin-resistant and methicillin-resistant Staphylococcus aureus (MRSA). The MICs at which 50% and 90% of bacteria were inhibited were ≥128 and ≥128 mg/liter, respectively, for ciprofloxacin, 16 and 32 mg/liter, respectively, for sparfloxacin, and 0.25 and 1 mg/liter, respectively, for Y-688. This new quinolone was further tested in rats with experimental endocarditis due to either of two isolates of ciprofloxacin-resistant MRSA (namely, P8/128 and CR1). Infected animals were treated for 3 days with ciprofloxacin, vancomycin, or Y-688. Antibiotics were administered through a computerized pump to simulate human-like pharmacokinetics in the serum of rats. The anticipated peak and trough levels of Y-688 were 4 and 1 mg/liter at 0.5 and 12 h, respectively. Treatment with ciprofloxacin was ineffective. Vancomycin significantly decreased vegetation bacterial counts for both organisms (P ≲ 0.05). In contrast, Y-688 only marginally decreased vegetation bacterial counts (P ≳ 0.05). Moreover, several vegetation that failed Y-688 treatment grew staphylococci for which the MICs of the test antibiotic were increased two to eight times. Y-688 also selected for resistance in vitro, and isolates for which the MICs were increased eight times emerged at a frequency of ca. 10−8. Thus, in spite of its low MIC for ciprofloxacin-resistant MRSA, Y-688 failed in vivo and its use carried the risk of resistance selection. The fact that ciprofloxacin-resistant staphylococci became rapidly resistant to this potent new drug suggests that the treatment of ciprofloxacin-resistant MRSA with new quinolones might be more problematic than expected.

scholarly journals Acute, subacute oral toxicity and Ames test of Py-mulin: an antibacterial drug candidate

2022 ◽  
Vol 23 (1) ◽  
Author(s):  
Yuan Fan ◽  
Yunxing Fu ◽  
Yuhang Zhou ◽  
Yu Liu ◽  
Baocheng Hao ◽  
...  
Keyword(s):  
Ames Test ◽  
Clinical Chemistry ◽  
Toxicity Study ◽  
Female Rats ◽  
Drug Candidate ◽  
Antibacterial Drug ◽  
Acute Oral Toxicity ◽  
Oral Toxicity

Abstract Background Py-mulin is a new pleuromutilin derivative with potent antibacterial activities in vitro and in vivo, suggesting this compound may lead to a promising antibacterial drug after further development. The present study is aimed to evaluate the acute and subacute oral toxicity, and the genotoxicity with the standard Ames test according to standard protocols. Methods Acute oral toxicity of Py-mulin was determined using Kunming mice. The 28-day repeated dose oral toxicity study in SD rats was performed according to OECD guideline No. 407. The bacterial reverse mutation (Ames test) was carried out using four Salmonella typhimurium (S. typhimurium) strains TA97, TA98, TA100 and TA1535 with and without S9 metabolic activation. Results The LD50 values in acute oral toxicity were 2973 mg/kg (female mice) and 3891 mg/kg (male mice) calculated by the Bliss method. In subacute toxicity study, 50 mg/kg Py-mulin did not induce any abnormality in body weight, food consumption, clinical sign, hematology, clinical chemistry, organ weight, and histopathology in all of the treatment groups. However, high doses of Py-mulin (100 and 300 mg/kg) displayed slightly hepatotoxicity to female rats. Furthermore, Py-mulin did not significantly increase the number of revertant colonies of four standard S. typhimurium strains with the doses of 0.16–1000 μg/plate in the Ames study. Conclusions Based on our findings, our study provides some information for the safety profile of Py-mulin.

scholarly journals Mycobacterium tuberculosis Gyrase Inhibitors as a New Class of Antitubercular Drugs

2015 ◽  
Vol 59 (4) ◽  
pp. 1868-1875 ◽  
Author(s):  
Delia Blanco ◽  
Esther Perez-Herran ◽  
Mónica Cacho ◽  
Lluís Ballell ◽  
Julia Castro ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Drug Discovery ◽  
Oral Absorption ◽  
Cell Activity ◽  
Cross Resistance ◽  
Drug Candidate ◽  
Antibacterial Drug ◽  
Gyrase Inhibitors

ABSTRACTOne way to speed up the TB drug discovery process is to search for antitubercular activity among compound series that already possess some of the key properties needed in anti-infective drug discovery, such as whole-cell activity and oral absorption. Here, we present MGIs, a new series ofMycobacterium tuberculosisgyrase inhibitors, which stem from the long-term efforts GSK has dedicated to the discovery and development of novel bacterial topoisomerase inhibitors (NBTIs). The compounds identified were found to be devoid of fluoroquinolone (FQ) cross-resistance and seem to operate through a mechanism similar to that of the previously described NBTI GSK antibacterial drug candidate. The remarkablein vitroandin vivoantitubercular profiles showed by the hits has prompted us to further advance the MGI project to full lead optimization.

scholarly journals An Improved Small-Molecule Inhibitor of FtsZ with SuperiorIn VitroPotency, Drug-Like Properties, andIn VivoEfficacy

2012 ◽  
Vol 57 (1) ◽  
pp. 317-325 ◽  
Author(s):  
Neil R. Stokes ◽  
Nicola Baker ◽  
James M. Bennett ◽  
Joanne Berry ◽  
Ian Collins ◽  
...  
Keyword(s):  
Small Molecule ◽  
Bacterial Load ◽  
Drug Candidate ◽  
Infection Model ◽  
Antibacterial Drug ◽  
Content Type ◽  
Intravenous And Oral Administration ◽  
Derivatives Of

ABSTRACTThe bacterial cell division protein FtsZ is an attractive target for small-molecule antibacterial drug discovery. Derivatives of 3-methoxybenzamide, including compound PC190723, have been reported to be potent and selective antistaphylococcal agents which exert their effects through the disruption of intracellular FtsZ function. Here, we report the further optimization of 3-methoxybenzamide derivatives towards a drug candidate. Thein vitroandin vivocharacterization of a more advanced lead compound, designated compound 1, is described. Compound 1 was potently antibacterial, with an average MIC of 0.12 μg/ml against all staphylococcal species, including methicillin- and multidrug-resistantStaphylococcus aureusandStaphylococcus epidermidis. Compound 1 inhibited anS. aureusstrain carrying the G196A mutation in FtsZ, which confers resistance to PC190723. Like PC190723, compound 1 acted on whole bacterial cells by blocking cytokinesis. No interactions between compound 1 and a diverse panel of antibiotics were measured in checkerboard experiments. Compound 1 displayed suitablein vitropharmaceutical properties and a favorablein vivopharmacokinetic profile following intravenous and oral administration, with a calculated bioavailability of 82.0% in mice. Compound 1 demonstrated efficacy in a murine model of systemicS. aureusinfection and caused a significant decrease in the bacterial load in the thigh infection model. A greater reduction in the number ofS. aureuscells recovered from infected thighs, equivalent to 3.68 log units, than in those recovered from controls was achieved using a succinate prodrug of compound 1, which was designated compound 2. In summary, optimized derivatives of 3-methoxybenzamide may yield a first-in-class FtsZ inhibitor for the treatment of antibiotic-resistant staphylococcal infections.

Tamarix articulata (T. articulata) - An Important Halophytic Medicinal Plant with Potential Pharmacological Properties

2019 ◽  
Vol 20 (4) ◽  
pp. 285-292 ◽  
Author(s):  
Abdullah M. Alnuqaydan ◽  
Bilal Rah
Keyword(s):  
Medicinal Plant ◽  
Biological Activities ◽  
Wide Spectrum ◽  
Biological Properties ◽  
In Vivo Model ◽  
Drug Candidate ◽  
Phytochemical Analysis ◽  
Pharmacological Properties

Background:Tamarix Articulata (T. articulata), commonly known as Tamarisk or Athal in Arabic region, belongs to the Tamaricaece species. It is an important halophytic medicinal plant and a good source of polyphenolic phytochemical(s). In traditional medicines, T. articulata extract is commonly used, either singly or in combination with other plant extracts against different ailments since ancient times.Methods:Electronic database survey via Pubmed, Google Scholar, Researchgate, Scopus and Science Direct were used to review the scientific inputs until October 2018, by searching appropriate keywords. Literature related to pharmacological activities of T. articulata, Tamarix species, phytochemical analysis of T. articulata, biological activities of T. articulata extracts. All of these terms were used to search the scientific literature associated with T. articulata; the dosage of extract, route of administration, extract type, and in-vitro and in-vivo model.Results:Numerous reports revealed that T. articulata contains a wide spectrum of phytochemical(s), which enables it to have a wide window of biological properties. Owing to the presence of high content of phytochemical compounds like polyphenolics and flavonoids, T. articulata is a potential source of antioxidant, anti-inflammatory and antiproliferative properties. In view of these pharmacological properties, T. articulata could be a potential drug candidate to treat various clinical conditions including cancer in the near future.Conclusion:In this review, the spectrum of phytochemical(s) has been summarized for their pharmacological properties and the mechanisms of action, and the possible potential therapeutic applications of this plant against various diseases discussed.

In Vitro and In Vivo Investigations into the Carbene Copper Bromide Anticancer Drug Candidate WBC4

2014 ◽  
Vol 11 (7) ◽  
pp. 825-832 ◽  
Author(s):  
Wolfgang Walther ◽  
Iduna Fichtner ◽  
Frauke Hackenberg ◽  
Wojciech Streciwilk ◽  
Matthias Tacke
Keyword(s):  
Anticancer Drug ◽  
Drug Candidate ◽  
Copper Bromide

scholarly journals In vitro and in vivo inhibition of malaria parasite infection by monoclonal antibodies against Plasmodium falciparum circumsporozoite protein (CSP)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Merricka C. Livingstone ◽  
Alexis A. Bitzer ◽  
Alish Giri ◽  
Kun Luo ◽  
Rajeshwer S. Sankhala ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Monoclonal Antibodies ◽  
Disease Burden ◽  
Vaccine Candidate ◽  
Specific Binding ◽  
Circumsporozoite Protein ◽  
Target Epitope ◽  
Selection Of

AbstractPlasmodium falciparum malaria contributes to a significant global disease burden. Circumsporozoite protein (CSP), the most abundant sporozoite stage antigen, is a prime vaccine candidate. Inhibitory monoclonal antibodies (mAbs) against CSP map to either a short junctional sequence or the central (NPNA)n repeat region. We compared in vitro and in vivo activities of six CSP-specific mAbs derived from human recipients of a recombinant CSP vaccine RTS,S/AS01 (mAbs 317 and 311); an irradiated whole sporozoite vaccine PfSPZ (mAbs CIS43 and MGG4); or individuals exposed to malaria (mAbs 580 and 663). RTS,S mAb 317 that specifically binds the (NPNA)n epitope, had the highest affinity and it elicited the best sterile protection in mice. The most potent inhibitor of sporozoite invasion in vitro was mAb CIS43 which shows dual-specific binding to the junctional sequence and (NPNA)n. In vivo mouse protection was associated with the mAb reactivity to the NANPx6 peptide, the in vitro inhibition of sporozoite invasion activity, and kinetic parameters measured using intact mAbs or their Fab fragments. Buried surface area between mAb and its target epitope was also associated with in vivo protection. Association and disconnects between in vitro and in vivo readouts has important implications for the design and down-selection of the next generation of CSP based interventions.

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