scholarly journals Praziquantel in a Clay Nanoformulation Shows More Bioavailability and Higher Efficacy against Murine Schistosoma mansoni Infection

2015 ◽  
Vol 59 (6) ◽  
pp. 3501-3508 ◽  
Author(s):  
Gina S. El-Feky ◽  
Wael S. Mohamed ◽  
Hanaa E. Nasr ◽  
Naglaa M. El-Lakkany ◽  
Sayed H. Seif el-Din ◽  
...  
Keyword(s):  
Schistosoma Mansoni ◽  
Rate Constant ◽  
Elimination Rate ◽  
New Drugs ◽  
Egg Load ◽  
Potential Cost ◽  
Time Curve ◽  
Content Type ◽  
Mmt Clay

ABSTRACTConsideration of existing compounds always simplifies and shortens the long and difficult process of discovering new drugs specifically for diseases of developing countries, an approach that may add to the significant potential cost savings. This study focused on improving the biological characteristics of the already-existing antischistosomal praziquantel (PZQ) by incorporating it into montmorillonite (MMT) clay as a delivery carrier to overcome its known bioavailability drawbacks. The oral bioavailability of a PZQ-MMT clay nanoformulation and itsin vivoefficacy againstSchistosoma mansoniwere investigated. The PZQ-MMT clay nanoformulation provided a preparation with a controlled release rate, a decrease in crystallinity, and an appreciable reduction in particle size. Uninfected and infected mice treated with PZQ-MMT clay showed 3.61- and 1.96-fold and 2.16- and 1.94-fold increases, respectively, in area under the concentration-time curve from 0 to 8 h (AUC0–8) and maximum concentration of drug in serum (Cmax), with a decrease in elimination rate constant (kel) by 2.84- and 1.35-fold and increases in the absorption rate constant (ka) and half-life (t1/2e) by 2.11- and 1.51-fold and 2.86- and 1.34-fold, respectively, versus the corresponding conventional PZQ-treated groups. This improved bioavailability has been expressed in higher efficacy of the drug, where the dose necessary to kill 50% of the worms was reduced by >3-fold (PZQ 50% effective dose [ED50] was 20.25 mg/kg of body weight for PZQ-MMT clay compared to 74.07 mg/kg for conventional PZQ), with significant reduction in total tissue egg load and increase in total immature, mature, and dead eggs in most of the drug-treated groups. This formulation showed better bioavailability, enhanced antischistosomal efficacy, and a safer profile despite the longer period of residence in the systemic circulation. Although the conventional drug's toxicity was not examined, animal mortality rates were not different between groups receiving the test PZQ-clay nanoformulation and conventional PZQ.

scholarly journals Effects of Tedizolid Phosphate on Survival Outcomes and Suppression of Production of Staphylococcal Toxins in a Rabbit Model of Methicillin-Resistant Staphylococcus aureus Necrotizing Pneumonia

2017 ◽  
Vol 61 (4) ◽  
Author(s):  
Vien T. M. Le ◽  
Hoan N. Le ◽  
Marcos Gabriel Pinheiro ◽  
Kenneth J. Hahn ◽  
Mary L. Dinh ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Bacterial Production ◽  
Protective Efficacy ◽  
Survival Rates ◽  
Rabbit Model ◽  
Rank Test ◽  
Necrotizing Pneumonia ◽  
Time Curve ◽  
Content Type

ABSTRACT The protective efficacy of tedizolid phosphate, a novel oxazolidinone that potently inhibits bacterial protein synthesis, was compared to those of linezolid, vancomycin, and saline in a rabbit model of Staphylococcus aureus necrotizing pneumonia. Tedizolid phosphate was administered to rabbits at 6 mg/kg of body weight intravenously twice daily, which yielded values of the 24-h area under the concentration-time curve approximating those found in humans. The overall survival rate was 83% for rabbits treated with 6 mg/kg tedizolid phosphate twice daily and 83% for those treated with 50 mg/kg linezolid thrice daily (P = 0.66 by the log-rank test versus the results obtained with tedizolid phosphate). These survival rates were significantly greater than the survival rates of 17% for rabbits treated with 30 mg/kg vancomycin twice daily (P = 0.003) and 17% for rabbits treated with saline (P = 0.002). The bacterial count in the lungs of rabbits treated with tedizolid phosphate was significantly decreased compared to that in the lungs of rabbits treated with saline, although it was not significantly different from that in the lungs of rabbits treated with vancomycin or linezolid. The in vivo bacterial production of alpha-toxin and Panton-Valentine leukocidin, two key S. aureus-secreted toxins that play critical roles in the pathogenesis of necrotizing pneumonia, in the lungs of rabbits treated with tedizolid phosphate and linezolid was significantly inhibited compared to that in the lungs of rabbits treated with vancomycin or saline. Taken together, these results indicate that tedizolid phosphate is superior to vancomycin for the treatment of S. aureus necrotizing pneumonia because it inhibits the bacterial production of lung-damaging toxins at the site of infection.

scholarly journals In VivoActivity of Aryl Ozonides against Schistosoma Species

2011 ◽  
Vol 56 (2) ◽  
pp. 1090-1092 ◽  
Author(s):  
Jennifer Keiser ◽  
Katrin Ingram ◽  
Mireille Vargas ◽  
Jacques Chollet ◽  
Xiaofang Wang ◽  
...  
Keyword(s):  
Schistosoma Mansoni ◽  
Worm Burden ◽  
Female Worm ◽  
Lead Compound ◽  
Content Type ◽  
Total Worm Burden

ABSTRACTWe evaluated thein vivoantischistosomal activities of 11 structurally diverse synthetic peroxides. Of all compounds tested, ozonide (1,2,4-trioxolane) OZ418 had the highest activity against adultSchistosoma mansoni, with total and female worm burden reductions of 80 and 90% (P< 0.05), respectively. Furthermore, treatment ofS. haematobium-infected mice with OZ418 reduced the total worm burden by 86%. In conclusion, OZ418 is a promising antischistosomal lead compound.

scholarly journals Pharmacodynamics of a Long-Acting Echinocandin, CD101, in a Neutropenic Invasive-Candidiasis Murine Model Using an Extended-Interval Dosing Design

2017 ◽  
Vol 62 (2) ◽  
Author(s):  
Alexander J. Lepak ◽  
Miao Zhao ◽  
Brian VanScoy ◽  
Paul G. Ambrose ◽  
David R. Andes
Keyword(s):  
Invasive Candidiasis ◽  
Half Life ◽  
Intraperitoneal Administration ◽  
Time Curve ◽  
Content Type ◽  
Elimination Half ◽  
Dosing Regimens ◽  
Dosing Strategies ◽  
Long Acting

ABSTRACT Echinocandins are important in the prevention and treatment of invasive candidiasis but limited by current dosing regimens that include daily intravenous administration. The novel echinocandin CD101 has a prolonged half-life of approximately 130 h in humans, making it possible to design once-weekly dosing strategies. The present study examined the pharmacodynamic activity of CD101 using the neutropenic invasive candidiasis mouse model against select Candida albicans (n = 4), C. glabrata (n = 3), and C. parapsilosis (n = 3) strains. The CD101 MIC ranged from 0.03 to 1 mg/liter. Plasma pharmacokinetic measurements were performed using uninfected mice after intraperitoneal administration of 1, 4, 16, and 64 mg/kg. The elimination half-life was prolonged at 28 to 41 h. Neutropenic mice were infected with each strain by lateral tail vein injection, treated with a single dose of CD101, and monitored for 7 days, at which time the organism burden was enumerated from the kidneys. Dose-dependent activity was observed for each organism. The pharmacokinetic/pharmacodynamic (PK/PD) index of the area under the concentration-time curve over 24 h in the steady state divided by the MIC (AUC/MIC index) correlated well with efficacy (R 2, 0.74 to 0.93). The median stasis 24-h free-drug AUC/MIC targets were as follows: for C. albicans, 2.92; for C. glabrata, 0.07; and for C. parapsilosis, 2.61. The PK/PD targets for 1-log10 kill endpoint were 2- to 4-fold higher. Interestingly, the aforementioned PK/PD targets of CD101 were numerically lower for all three species than those of other echinocandins. In summary, CD101 is a promising, novel echinocandin with advantageous pharmacokinetic properties and potent in vivo pharmacodynamic activity.

scholarly journals MBX-500, a Hybrid Antibiotic withIn VitroandIn VivoEfficacy against Toxigenic Clostridium difficile

2012 ◽  
Vol 56 (9) ◽  
pp. 4786-4792 ◽  
Author(s):  
Michelle M. Butler ◽  
Dean L. Shinabarger ◽  
Diane M. Citron ◽  
Ciarán P. Kelly ◽  
Sofya Dvoskin ◽  
...  
Keyword(s):  
Weight Gain ◽  
Clostridium Difficile ◽  
Severe Disease ◽  
Normal Weight ◽  
New Drugs ◽  
Hamster Model ◽  
Resistance Development ◽  
Content Type

ABSTRACTClostridium difficileinfection (CDI) causes moderate to severe disease, resulting in diarrhea and pseudomembranous colitis. CDI is difficult to treat due to production of inflammation-inducing toxins, resistance development, and high probability of recurrence. Only two antibiotics are approved for the treatment of CDI, and the pipeline for therapeutic agents contains few new drugs. MBX-500 is a hybrid antibacterial, composed of an anilinouracil DNA polymerase inhibitor linked to a fluoroquinolone DNA gyrase/topoisomerase inhibitor, with potential as a new therapeutic for CDI treatment. Since MBX-500 inhibits three bacterial targets, it has been previously shown to be minimally susceptible to resistance development. In the present study, thein vitroandin vivoefficacies of MBX-500 were explored against the Gram-positive anaerobe,C. difficile. MBX-500 displayed potency across nearly 50 isolates, including those of the fluoroquinolone-resistant, toxin-overproducing NAP1/027 ribotype, performing as well as comparator antibiotics vancomycin and metronidazole. Furthermore, MBX-500 was a narrow-spectrum agent, displaying poor activity against many other gut anaerobes. MBX-500 was active in acute and recurrent infections in a toxigenic hamster model of CDI, exhibiting full protection against acute infections and prevention of recurrence in 70% of the animals. Hamsters treated with MBX-500 displayed significantly greater weight gain than did those treated with vancomycin. Finally, MBX-500 was efficacious in a murine model of CDI, again demonstrating a fully protective effect and permitting near-normal weight gain in the treated animals. These selective anti-CDI features support the further development of MBX 500 for the treatment of CDI.

scholarly journals A Novel Piperazine-Based Drug Lead for Cryptosporidiosis from the Medicines for Malaria Venture Open-Access Malaria Box

2018 ◽  
Vol 62 (4) ◽  
pp. e01505-17 ◽  
Author(s):  
R. S. Jumani ◽  
K. Bessoff ◽  
M. S. Love ◽  
P. Miller ◽  
E. E. Stebbins ◽  
...  
Keyword(s):  
Mouse Model ◽  
Drug Development ◽  
Early Stage ◽  
New Drugs ◽  
Cryptosporidium Hominis ◽  
Content Type ◽  
Knockout Mouse Model ◽  
Malaria Box

ABSTRACTCryptosporidiosis causes life-threatening diarrhea in children under the age of 5 years and prolonged diarrhea in immunodeficient people, especially AIDS patients. The standard of care, nitazoxanide, is modestly effective in children and ineffective in immunocompromised individuals. In addition to the need for new drugs, better knowledge of drug properties that drivein vivoefficacy is needed to facilitate drug development. We report the identification of a piperazine-based lead compound forCryptosporidiumdrug development, MMV665917, and a new pharmacodynamic method used for its characterization. The identification of MMV665917 from the Medicines for Malaria Venture Malaria Box was followed by dose-response studies,in vitrotoxicity studies, and structure-activity relationship studies using commercial analogues. The potency of this compound againstCryptosporidium parvumIowa and field isolates was comparable to that againstCryptosporidium hominis. Furthermore, unlike nitazoxanide, clofazimine, and paromomycin, MMV665917 appeared to be curative in a NOD SCID gamma mouse model of chronic cryptosporidiosis. MMV665917 was also efficacious in a gamma interferon knockout mouse model of acute cryptosporidiosis. To determine if efficacy in this mouse model of chronic infection might relate to whether compounds are parasiticidal or parasitistatic forC. parvum, we developed a novelin vitroparasite persistence assay. This assay suggested that MMV665917 was parasiticidal, unlike nitazoxanide, clofazimine, and paromomycin. The assay also enabled determination of the concentration of the compound required to maximize the rate of parasite elimination. This time-kill assay can be used to prioritize early-stageCryptosporidiumdrug leads and may aid in planningin vivoefficacy experiments. Collectively, these results identify MMV665917 as a promising lead and establish a new method for characterizing potential anticryptosporidial agents.

scholarly journals In Vivo Pharmacodynamic Characterization of a Novel Odilorhabdin Antibiotic, NOSO-502, against Escherichia coli and Klebsiella pneumoniae in a Murine Thigh Infection Model

2018 ◽  
Vol 62 (9) ◽  
Author(s):  
Miao Zhao ◽  
Alexander J. Lepak ◽  
Karen Marchillo ◽  
Jamie VanHecker ◽  
David R. Andes
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Subcutaneous Administration ◽  
Dose Fractionation ◽  
Infection Model ◽  
Pharmacokinetic Studies ◽  
Time Curve ◽  
Content Type ◽  
The Mean

ABSTRACT NOSO-502 is a novel odilorhabdin antibiotic with potent activity against Enterobacteriaceae. The goal of these studies was to determine which pharmacokinetic/pharmacodynamic (PK/PD) indices and magnitude best correlated with efficacy in the murine thigh infection model. Six Escherichia coli and 6 Klebsiella pneumoniae isolates were utilized. MICs were determined using CLSI methods and ranged from 1 to 4 mg/liter. A neutropenic murine thigh infection model was utilized for all treatment studies. Single-dose plasma pharmacokinetics were determined in mice after subcutaneous administration of 7.81, 31.25, 125, and 500 mg/kg of body weight. Pharmacokinetic studies exhibited peak concentration (Cmax) values of 1.49 to 84.6 mg/liter, area under the concentration-time curve from 0 h to infinity (AUC0–∞) values of 1.94 to 352 mg · h/liter, and beta elimination half-lives of 0.41 to 1.1 h. Dose fractionation studies were performed using total drug doses of 7.81 mg/kg to 2,000 mg/kg fractionated into regimens of every 3 h (q3h), q6h, q12h, or q24h. Nonlinear regression analysis demonstrated that AUC/MIC was the PK/PD parameter that best correlated with efficacy (R2, 0.86). In subsequent studies, we used the neutropenic murine thigh infection model to determine the magnitude of NOSO-502 AUC/MIC needed for the efficacy against a diverse group of Enterobacteriaceae. Mice were treated with 4-fold-increasing doses (range, 3.91 to 1,000 mg/kg) of NOSO-502 every 6 h. The mean 24-h free-drug AUC/MIC (fAUC)/MIC) magnitudes associated with net stasis and 1-log kill endpoint for K. pneumoniae were 4.22 and 17.7, respectively. The mean fAUC/MIC magnitude associated with net stasis endpoint for E. coli was 10.4. NOSO-502 represents a promising novel, first-in-class odilorhabdin antibiotic with in vivo potency against Enterobacteriaceae.

scholarly journals In Vivo Bioluminescent Monitoring of Therapeutic Efficacy and Pharmacodynamic Target Assessment of Antofloxacin against Escherichia coli in a Neutropenic Murine Thigh Infection Model

2017 ◽  
Vol 62 (1) ◽  
Author(s):  
Yu-Feng Zhou ◽  
Meng-Ting Tao ◽  
Yu-Zhang He ◽  
Jian Sun ◽  
Ya-Hong Liu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Subcutaneous Administration ◽  
Free Drug ◽  
Infection Model ◽  
Bioluminescent Imaging ◽  
Time Curve ◽  
Content Type ◽  
E Coli ◽  
Tract Infections

ABSTRACT Antimicrobial resistance among uropathogens has increased the rates of infection-related morbidity and mortality. Antofloxacin is a novel fluoroquinolone with broad-spectrum antibacterial activity against urinary Gram-negative bacilli, such as Escherichia coli. This study monitored the in vivo efficacy of antofloxacin using bioluminescent imaging and determined pharmacokinetic (PK)/pharmacodynamic (PD) targets against E. coli isolates in a neutropenic murine thigh infection model. The PK properties were determined after subcutaneous administration of antofloxacin at 2.5, 10, 40, and 160 mg/kg of body weight. Following thigh infection, the mice were treated with 2-fold-increasing doses of antofloxacin from 2.5 to 80 mg/kg administered every 12 h. Efficacy was assessed by quantitative determination of the bacterial burdens in thigh homogenates and was compared with the bioluminescent density. Antofloxacin demonstrated both static and killing endpoints in relation to the initial burden against all study strains. The PK/PD index area under the concentration-time curve (AUC)/MIC correlated well with efficacy (R 2 = 0.92), and the dose-response relationship was relatively steep, as observed with escalating doses of antofloxacin. The mean free drug AUC/MIC targets necessary to produce net bacterial stasis and 1-log10 and 2-log10 kill for each isolate were 38.7, 66.1, and 147.0 h, respectively. In vivo bioluminescent imaging showed a rapid decrease in the bioluminescent density at free drug AUC/MIC exposures that exceeded the stasis targets. The integration of these PD targets combined with the results of PK studies with humans will be useful in setting optimal dosing regimens for the treatment of urinary tract infections due to E. coli.

scholarly journals Efficacy of NZ2114, a Novel Plectasin-Derived Cationic Antimicrobial Peptide Antibiotic, in Experimental Endocarditis Due to Methicillin-Resistant Staphylococcus aureus

2011 ◽  
Vol 55 (11) ◽  
pp. 5325-5330 ◽  
Author(s):  
Yan Q. Xiong ◽  
Wessam Abdel Hady ◽  
Antoine Deslandes ◽  
Astrid Rey ◽  
Laurent Fraisse ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Maximum Effect ◽  
Peptide Antibiotic ◽  
Time Curve ◽  
Cationic Antimicrobial Peptide ◽  
Unbound Fraction ◽  
Methicillin Resistant ◽  
Content Type ◽  
Conventional Antibiotics

ABSTRACTCationic antimicrobial peptides (CAPs) play important roles in host immune defenses. Plectasin is a defensin-like CAP isolated from the saprophytic fungusPseudoplectania nigrella. NZ2114 is a novel variant of plectasin with potent activity against Gram-positive bacteria. In this study, we investigated (i) thein vivopharmacokinetic and pharmacodynamic (PK/PD) characteristics of NZ2114 and (ii) thein vivoefficacy of NZ2114 in comparison with those of two conventional antibiotics, vancomycin or daptomycin, in an experimental rabbit infective endocarditis (IE) model due to a methicillin-resistantStaphylococcus aureus(MRSA) strain (ATCC 33591). All NZ2114 regimens (5, 10, and 20 mg/kg of body weight, intravenously [i.v.], twice daily for 3 days) significantly decreased MRSA densities in cardiac vegetations, kidneys, and spleen versus those in untreated controls, except in one scenario (5 mg/kg, splenic MRSA counts). The efficacy of NZ2114 was clearly dose dependent in all target tissues. At 20 mg/kg, NZ2114 showed a significantly greater efficacy than vancomycin (P< 0.001) and an efficacy similar to that of daptomycin. Of importance, only NZ2114 (in 10- and 20-mg/kg regimens) prevented posttherapy relapse in cardiac vegetations, kidneys, and spleen, while bacterial counts in these target tissues continued to increase in vancomycin- and daptomycin-treated animals. Thesein vivoefficacies were equivalent and significantly correlated with three PK indices investigated:fCmax/MIC (the maximum concentration of the free, unbound fraction of a drug in serum divided by the MIC),fAUC/MIC (where AUC is the area under the concentration-time curve), andf%T>MIC(%T>MICis the cumulative percentage of a 24-h period that the drug concentration exceeds the MIC under steady-state pharmacokinetic conditions), as analyzed by a sigmoid maximum-effect (Emax) model (R2> 0.69). The superior efficacy of NZ2114 in this MRSA IE model suggests the potential for further development of this compound for treating serious MRSA infections.

scholarly journals In Vivo Pharmacodynamic Evaluation of Omadacycline against Staphylococcus aureus in the Neutropenic Mouse Pneumonia Model

2019 ◽  
Vol 64 (2) ◽  
Author(s):  
Alexander J. Lepak ◽  
Miao Zhao ◽  
Karen Marchillo ◽  
Jamie VanHecker ◽  
David R. Andes
Keyword(s):  
Staphylococcus Aureus ◽  
Therapeutic Effect ◽  
Bacterial Pneumonia ◽  
Epithelial Lining ◽  
Time Curve ◽  
Epithelial Lining Fluid ◽  
Content Type ◽  
Concentration Time ◽  
Mrsa Strains

ABSTRACT Omadacycline is an effective therapy for community-acquired bacterial pneumonia (CABP). Given its potent activity against methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA), we sought to determine the pharmacodynamic activity and target pharmacokinetic/pharmacodynamic (PK/PD) exposures associated with a therapeutic effect in the neutropenic mouse pneumonia model against 10 MSSA/MRSA strains. The area under the concentration-time curve (AUC)/MIC associated with 1-log kill was noted at 24-h epithelial lining fluid (ELF) and plasma AUC/MIC exposures of ∼2 (ELF range, <0.93 to 19; plasma range, <1.06 to 17) and 2-log kill was noted at 24-h ELF and plasma AUC/MIC exposures of ∼12 (ELF range, 2.5 to 130; plasma range, 3.5 to 151).

Limited Sampling Strategies to Estimate the Area under the Concentration-time Curve

2012 ◽  
Vol 51 (05) ◽  
pp. 383-394 ◽  
Author(s):  
M. Fukumoto ◽  
L. Bax ◽  
A. Kohno ◽  
Y. Morishita ◽  
H. Tsuruta
Keyword(s):  
Rate Constant ◽  
Elimination Rate ◽  
Estimation Method ◽  
Pharmacokinetic Parameters ◽  
Good Precision ◽  
Sampling Strategies ◽  
Time Curve ◽  
New Methods ◽  
Limited Sampling ◽  
Concentration Time

SummaryBackground: Over 100 limited sampling strategies (LSSs) have been proposed to reduce the number of blood samples necessary to estimate the area under the concentration-time curve (AUC). The conditions under which these strategies succeed or fail remain to be clarified.Objectives: We investigated the accuracy of existing LSSs both theoretically and numerically by Monte Carlo simulation. We also proposed two new methods for more accurate AUC estimations.Methods: We evaluated the following existing methods theoretically: i) nonlinear curve fitting algorithm (NLF), ii) the trapezium rule with exponential curve approximation (TZE), and iii) multiple linear regression (MLR). Taking busulfan (BU) as a test drug, we generated a set of theoretical concentration-time curves based on the identified distribution of pharmacokinetic parameters of BU and re-evaluated the existing LSSs using these virtual validation profiles. Based on the evaluation results, we improved the TZE so that unrealistic parameter values were not used. We also proposed a new estimation method in which the most likely curve was selected from a set of pre-generated theoretical concentration-time curves.Results: Our evaluation, based on clinical profiles and a virtual validation set, revealed: i) NLF sometimes overestimated the absorption rate constant Ka, ii) TZE overestimated AUC over 280% when Ka is small, and iii) MLR underestimated AUC over 30% when the elimination rate constant Ke is small. These results were consistent with our mathematical evaluations for these methods. In contrast, our two new methods had little bias and good precision.Conclusions: Our investigation revealed that existing LSSs induce different but specific biases in the estimation of AUC. Our two new LSSs, a modified TZE and one using model concentration-time curves, provided accurate and precise estimations of AUC.

Sign in / Sign up

Export Citation Format

Share Document