Doxorubicin concentration time course in the myocardium after single administration to the dog

1987 ◽  
Vol 20 (3) ◽  
pp. 267-269 ◽  
Author(s):  
Quadiri Timour ◽  
Patrice Nony ◽  
Jean Lang ◽  
Mohamed Lakhal ◽  
V�ronique Trillet ◽  
...  
Keyword(s):  
Time Course ◽  
Single Administration ◽  
Concentration Time ◽  
Doxorubicin Concentration

scholarly journals Pharmacological Basis of CD101 Efficacy: Exposure Shape Matters

2017 ◽  
Vol 61 (11) ◽  
Author(s):  
Elizabeth A. Lakota ◽  
Justin C. Bader ◽  
Voon Ong ◽  
Ken Bartizal ◽  
Lynn Miesel ◽  
...  
Keyword(s):  
Time Course ◽  
Fungicidal Activity ◽  
Control Group ◽  
Time Curve ◽  
Content Type ◽  
Treatment Groups ◽  
Concentration Time ◽  
Treatment Control Group ◽  
Pharmacological Basis

ABSTRACT CD101 is a novel echinocandin with concentration-dependent fungicidal activity in vitro and a long half-life (∼133 h in humans, ∼70 to 80 h in mice). Given these characteristics, it is likely that the shape of the CD101 exposure (i.e., the time course of CD101 concentrations) influences efficacy. To test this hypothesis, doses which produce the same total area under the concentration-time curve (AUC) were administered to groups of neutropenic ICR mice infected with Candida albicans R303 using three different schedules. A total CD101 dose of 2 mg/kg was administered as a single intravenous (i.v.) dose or in equal divided doses of either 1 mg/kg twice weekly or 0.29 mg/kg/day over 7 days. The studies were performed using a murine disseminated candidiasis model. Animals were euthanized at 168 h following the start of treatment. Fungi grew well in the no-treatment control group and showed variable changes in fungal density in the treatment groups. When the CD101 AUC from 0 to 168 h (AUC0–168) was administered as a single dose, a >2 log10 CFU reduction from the baseline at 168 h was observed. When twice-weekly and daily regimens with similar AUC values were administered, net fungal stasis and a >1 log10 CFU increase from the baseline were observed, respectively. These data support the hypothesis that the shape of the CD101 AUC influences efficacy. Thus, CD101 administered once per week demonstrated a greater degree of fungal killing than the same dose divided into twice-weekly or daily regimens.

scholarly journals Meropenem Combined with Ciprofloxacin Combats Hypermutable Pseudomonas aeruginosa from Respiratory Infections of Cystic Fibrosis Patients

2018 ◽  
Vol 62 (11) ◽  
Author(s):  
Vanessa E. Rees ◽  
Rajbharan Yadav ◽  
Kate E. Rogers ◽  
Jürgen B. Bulitta ◽  
Veronika Wirth ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Time Course ◽  
Respiratory Infections ◽  
Resistant Bacteria ◽  
Infection Model ◽  
Time Curve ◽  
Bacterial Killing ◽  
Content Type ◽  
Concentration Time

ABSTRACT Hypermutable Pseudomonas aeruginosa organisms are prevalent in chronic respiratory infections and have been associated with reduced lung function in cystic fibrosis (CF); these isolates can become resistant to all antibiotics in monotherapy. This study aimed to evaluate the time course of bacterial killing and resistance of meropenem and ciprofloxacin in combination against hypermutable and nonhypermutable P. aeruginosa. Static concentration time-kill experiments over 72 h assessed meropenem and ciprofloxacin in mono- and combination therapies against PAO1 (nonhypermutable), PAOΔmutS (hypermutable), and hypermutable isolates CW8, CW35, and CW44 obtained from CF patients with chronic respiratory infections. Meropenem (1 or 2 g every 8 h [q8h] as 3-h infusions and 3 g/day as a continuous infusion) and ciprofloxacin (400 mg q8h as 1-h infusions) in monotherapies and combinations were further evaluated in an 8-day hollow-fiber infection model study (HFIM) against CW44. Concentration-time profiles in lung epithelial lining fluid reflecting the pharmacokinetics in CF patients were simulated and counts of total and resistant bacteria determined. All data were analyzed by mechanism-based modeling (MBM). In the HFIM, all monotherapies resulted in rapid regrowth with resistance at 48 h. The maximum daily doses of 6 g meropenem (T>MIC of 80% to 88%) and 1.2 g ciprofloxacin (area under the concentration-time curve over 24 h in the steady state divided by the MIC [AUC/MIC], 176), both given intermittently, in monotherapy failed to suppress regrowth and resulted in substantial emergence of resistance (≥7.6 log10 CFU/ml resistant populations). The combination of these regimens achieved synergistic killing and suppressed resistance. MBM with subpopulation and mechanistic synergy yielded unbiased and precise curve fits. Thus, the combination of 6 g/day meropenem plus ciprofloxacin holds promise for future clinical evaluation against infections by susceptible hypermutable P. aeruginosa.

scholarly journals Evaluation of Tobramycin and Ciprofloxacin as a Synergistic Combination Against Hypermutable Pseudomonas Aeruginosa Strains via Mechanism-Based Modelling

Pharmaceutics ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 470 ◽  
Author(s):  
Vanessa E. Rees ◽  
Jürgen B. Bulitta ◽  
Antonio Oliver ◽  
Roger L. Nation ◽  
Cornelia B. Landersdorfer
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Time Course ◽  
Respiratory Infections ◽  
Resistant Bacteria ◽  
Bacterial Killing ◽  
Concentration Time ◽  
Colony Forming Units ◽  
Static Concentration ◽  
Susceptible Populations ◽  
Time Kill

Hypermutable Pseudomonas aeruginosa strains have a greatly increased mutation rate and are prevalent in chronic respiratory infections. Initially, we systematically evaluated the time-course of total and resistant populations of hypermutable (PAO∆mutS) and non-hypermutable (PAO1) P. aeruginosa strains in 48-h static concentration time-kill studies with two inocula. Both strains were exposed to clinically relevant concentrations of important antibiotics (aztreonam, ceftazidime, imipenem, meropenem, tobramycin, and ciprofloxacin) in monotherapy. The combination of tobramycin and ciprofloxacin was subsequently assessed in 48-h static concentration time-kill studies against PAO1, PAO∆mutS, and two hypermutable clinical P. aeruginosa strains. Mechanism-based mathematical modelling was conducted to describe the time-course of total and resistant bacteria for all four strains exposed to the combination. With all monotherapies, bacterial regrowth and resistant populations were overall more pronounced for PAO∆mutS compared to PAO1. The combination of tobramycin and ciprofloxacin was synergistic, with up to 106.1 colony forming units (CFU)/mL more bacterial killing than the most active monotherapy for all strains, and largely suppressed less-susceptible populations. This work indicates that monotherapies against hypermutable P. aeruginosa strains are not a viable option. Tobramycin with ciprofloxacin was identified as a promising and tangible option to combat hypermutable P. aeruginosa strains.

Tissue distribution, kinetics, and biologic half-life of Mg28 in the dog

1963 ◽  
Vol 204 (6) ◽  
pp. 1086-1094 ◽  
Author(s):  
R. Lazzara ◽  
K. Hyatt ◽  
W. D. Love ◽  
J. Cronvich ◽  
G. E. Burch
Keyword(s):  
Tissue Distribution ◽  
Half Life ◽  
Time Course ◽  
Specific Activity ◽  
High Specific Activity ◽  
Fecal Excretion ◽  
Concentration Time ◽  
Distribution Kinetics ◽  
Flame Spectrophotometry ◽  
Different Tissues

Mg28 of a high specific activity was used in these studies. It was rapidly injected intravenously into 12 dogs and the concentration-time course curves in plasma were obtained. Urinary and fecal excretion was followed in seven animals. The dogs were killed 7 min to 68 hr following injection. Seventy-four tissues were sampled and assayed for Mg28 concentration. Plasma Mg24 was determined by flame spectrophotometry. With these data it was possible to follow the concentration-time course of Mg28 in the various tissues as well as to calculate their "exchanging" Mg24 content and effective rates of exchange. A variation in the pattern of uptake and in concentration of exchanging Mg24 was noted among the different tissues. During the interval from 24–68 hr, body exchanging Mg24 space and mass were found to range from 3.2–3.8 liters/kg and 4.9–5.7 mEq/kg, respectively. The biologic half-life of Mg28 in the dog estimated from excretion data was 11 days.

scholarly journals Comparisons between Antimicrobial Pharmacodynamic Indices and Bacterial Killing as Described by Using the Zhi Model

1998 ◽  
Vol 42 (7) ◽  
pp. 1731-1737 ◽  
Author(s):  
S. Corvaisier ◽  
P. H. Maire ◽  
M. Y. Bouvier d’yvoire ◽  
X. Barbaut ◽  
N. Bleyzac ◽  
...  
Keyword(s):  
Bacterial Growth ◽  
Time Course ◽  
Composite Index ◽  
Relative Number ◽  
Good Sensitivity ◽  
Time Curve ◽  
Bacterial Killing ◽  
Concentration Time ◽  
Time Courses ◽  
Over Time

ABSTRACT Various suggestions have been made for empirical pharmacodynamic indices of antibiotic effectiveness, such as areas under the drug concentration-time curve in serum (AUC), AUC>MIC, AUC/MIC, area under the inhibitory curve (AUIC), AUC above MIC, and time above MIC (T>MIC). In addition, bacterial growth and killing models, such as the Zhi model, have been developed. The goal of the present study was to compare the empirical behavior of the Zhi model of bacterial growth and killing with the other empirical pharmacodynamic indices described above by using simulated clinical data analyzed with the USC*PACK PC clinical programs for adaptive control of drug therapy, with one model describing a concentration-dependent antibiotic (tobramycin) and another describing a concentration-independent antibiotic (ticarcillin). The computed relative number of CFU was plotted against each pharmacodynamic index, with each axis parameterized over time. We assumed that a good pharmacodynamic index should present a clear and continuous relationship between the time course of its values and the time course of the bacterial killing as seen with the Zhi model. Preliminary work showed that some pharmacodynamic indices were very similar. A good sensitivity to the change in the values of the MIC was shown for AUC/MIC and also forT>MIC. In addition, the time courses of some other pharmacodynamic indices were very similar. Since AUC/MIC is easily calculated and shows more sensitivity, it appeared to be the best of the indices mentioned above for the concentration-dependent drug, because it incorporated and used the MIC the best. T>MIC appeared to be the best index for a concentration-independent drug. We also propose a new composite index, weighted AUC (WAUC), which appears to be useful for both concentration-dependent and concentration-independent drugs.

scholarly journals Penetration of GSK1322322 into Epithelial Lining Fluid and Alveolar Macrophages as Determined by Bronchoalveolar Lavage

2013 ◽  
Vol 58 (1) ◽  
pp. 419-423 ◽  
Author(s):  
Odin J. Naderer ◽  
Keith A. Rodvold ◽  
Lori S. Jones ◽  
John Z. Zhu ◽  
Chester L. Bowen ◽  
...  
Keyword(s):  
Bronchoalveolar Lavage ◽  
Alveolar Macrophages ◽  
Bacterial Infections ◽  
Time Course ◽  
Respiratory Pathogens ◽  
Epithelial Lining ◽  
Time Curve ◽  
Epithelial Lining Fluid ◽  
Concentration Time

ABSTRACTGSK1322322 is a potent peptide deformylase inhibitor within vitroandin vivoactivity against multidrug-resistant skin and respiratory pathogens. This report provides plasma and intrapulmonary pharmacokinetics, safety, and tolerability of GSK1322322 after repeat (twice daily intravenous dosing for 4 days) dosing at 1,500 mg. Plasma samples were collected over the last 12-hour dosing interval of repeat dosing following the day 4 morning dose (the last dose). Bronchoalveolar lavage samples were collected once in each subject, either before or at 2 or 6 h after the last intravenous dose. Plasma area under the concentration-time curve (AUC0–τ) was 66.7 μg · h/ml, and maximum concentration of drug in serum (Cmax) was 25.4 μg/ml following repeat doses of intravenous GSK1322322. The time course of epithelial lining fluid (ELF) and alveolar macrophages (AM) mirrored the plasma concentration-time profile. The AUC0–τfor ELF and AM were 78.9 μg · h/ml and 169 μg · h/ml, respectively. The AUC0–τratios of ELF and AM to total plasma were 1.2 and 2.5, respectively. These ratios increased to 3.5 and 7.4, respectively, when unbound plasma was considered. These results are supportive of GSK1322322 as a potential antimicrobial agent for the treatment of lower respiratory tract bacterial infections caused by susceptible pathogens. (This study has been registered atClinicalTrials.govunder registration number NCT01610388.)

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