scholarly journals Pharmacokinetic/Pharmacodynamic Modeling of Spiramycin against Mycoplasma synoviae in Chickens

Pathogens ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1238
Author(s):  
Sara T. Elazab ◽  
Nahla S. Elshater ◽  
Yousreya H. Hashem ◽  
Nayera M. Al-Atfeehy ◽  
Eon-Bee Lee ◽  
...  
Keyword(s):  
Oral Dose ◽  
Inhibitory Concentration ◽  
Oral Treatment ◽  
Pharmacodynamic Modeling ◽  
Parallel Study ◽  
Withdrawal Period ◽  
Time Curve ◽  
Mycoplasma Synoviae ◽  
Concentration Time ◽  
Plasma Concentration Time Curve

This research aimed to assess the pharmacokinetics/pharmacodynamics (PK/PD) and tissue residues of spiramycin in chickens. The PK of spiramycin were determined in 12 chickens using a parallel study design in which each group of chickens (n = 6) received a single dose of spiramycin at 17 mg/kg intravenously (IV) or orally. Plasma samples were collected at assigned times for up to 48 h to measure spiramycin concentrations. Additionally, a tissue depletion study was performed in 42 chickens receiving spiramycin at 17 mg/kg/day orally for 7 days. The area under the plasma concentration–time curve values were 29.94 ± 4.74 and 23.11 ± 1.83 µg*h/mL after IV and oral administrations, respectively. The oral bioavailability was 77.18%. The computed withdrawal periods of spiramycin were 11, 10, and 7 days for liver, muscle, and skin and fat, respectively. The minimum inhibitory concentration for spiramycin against Mycoplasma synoviae (M. synoviae) strain 1853 was 0.0625 µg/mL. Using the PK/PD integration, the appropriate oral dose of spiramycin against M. synoviae was estimated to be 15.6 mg/kg. Thus, we recommend an oral dose of 15.6 mg spiramycin/kg against M. synoviae in chickens and a withdrawal period of 11 days following oral treatment with 17 mg spiramycin/kg/day for 7 days.

Charcoal and Isoniazid Pharmacokinetics

1986 ◽  
Vol 5 (4) ◽  
pp. 285-286 ◽  
Author(s):  
N. Scolding ◽  
M.J. Ward ◽  
A. Hutchings ◽  
P.A. Routledge
Keyword(s):  
Plasma Concentration ◽  
Oral Dose ◽  
Activated Charcoal ◽  
Healthy Subjects ◽  
Time Curve ◽  
Concentration Time ◽  
Plasma Concentration Time Curve

Activated charcoal (10 g) administered 1 h after a 600 mg oral dose of isoniazid to six healthy subjects did not reduce the area under the plasma concentration-time curve for isoniazid significantly. Charcoal administration is unlikely to be of value in isoniazid poisoning if delayed by an hour or more after the overdose.

scholarly journals Pharmacokinetics and Bioequivalence Study of Two Ciprofloxacin Hydrochloride Tablets in Chinese Healthy Volunteers Under Fasting and Fed Conditions: A Randomized, Open-Label, Two-Formulation, Two-Sequence, Two-Period, Single-Dose Crossover Study.

2020 ◽  
Author(s):  
Fei Qin ◽  
Gan-Mi Wang ◽  
Jin-Ying Huang ◽  
Jia-Rong Wu ◽  
Wen-Jie Song ◽  
...  
Keyword(s):  
Single Dose ◽  
Plasma Concentration ◽  
Oral Dose ◽  
Single Oral Dose ◽  
Pharmacokinetic Parameters ◽  
Open Label ◽  
Time Curve ◽  
Ciprofloxacin Hydrochloride ◽  
Concentration Time ◽  
Plasma Concentration Time Curve

Abstract BackgroundCiprofloxacin is a broad-spectrum fluoroquinolone antibiotic which is active against a wide range of Gram-positive and Gram-negative bacteria. The study mainly aimed to determine the bioequivalence of two branded ciprofloxacin hydrochloride tablets (250 mg) under the fasting and fed conditions.MethodsThe study was carried out in 48 healthy Chinese subjects under fasting and fed conditions with a randomized, open-label, two-formulation, two-sequence, two-period, single-dose crossover design. In each period of the study, the subjects were assigned to receive a single oral dose of 250 mg of ciprofloxacin hydrochloride. Blood samples were collected from an hour before dosing to 36 h after administration with 16 time points in total. The bioequivalence analysis was performed after ln-transformation of the ciprofloxacin pharmacokinetic parameters including maximum concentration (Cmax), area under the plasma concentration–time curve from time 0 to time t (AUC0-t), area under the plasma concentration-time curve from time 0 to infinity (AUC0-∞). Two formulations are considered bioequivalent if the 90% confidence intervals (CIs) for the test/reference geometric mean ratios (GMRs) for the ln-transformed pharmacokinetic parameters fall within the standard acceptance range of 80% – 125%. ResultsIn total of 48 subjects were enrolled in the fasting and fed studies, and one of the subjects was excluded before the administration. In the fasting study, the 90% CIs for the test/reference GMRs of the ln-transformed data for Cmax, AUC0–t, and AUC0–∞ were 85.41% to 100.97%, 95.40% to 100.27%, and 95.48% to 100.30%, respectively. For the fed study, the 90% CIs for the test/reference GMRs of the ln-transformed data for Cmax, AUC0–t, and AUC0–∞ were 90.15% to 113.75%, 99.10% to 103.77% and 99.11% to 103.80%, respectively. A total of 8 of 47 subjects experienced AEs in the fasting and fed studies.ConclusionsIn the study, the generic (test) product of ciprofloxacin hydrochloride 250 mg was bioequivalent to the innovator (reference) product after a single oral dose administration under the fasting and fed conditions. Both two brands of ciprofloxacin tablets were safe and well tolerated.Trial registrationThe clinical trial was registered at Center for the Drug Evaluation of the National Medical Products Administration (registration number: CTR20171152; date of registration：September 25, 2017; http://www.chinadrugtrials.org.cn/clinicaltrials.searchlistdetail.dhtml).

scholarly journals Evidence for Establishing the Clinical Breakpoint of Cefquinome against Haemophilus Parasuis in China

Pathogens ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 105
Author(s):  
Kun Mi ◽  
Da Sun ◽  
Mei Li ◽  
Haihong Hao ◽  
Kaixiang Zhou ◽  
...  
Keyword(s):  
Monte Carlo Simulation ◽  
Antibacterial Activity ◽  
Inhibitory Concentration ◽  
High Morbidity ◽  
Haemophilus Parasuis ◽  
Wild Type ◽  
Time Curve ◽  
Resistance Change ◽  
Concentration Time ◽  
Clinical Experiments

Haemophilus parasuis can cause high morbidity and mortality in swine. Cefquinome possesses excellent antibacterial activity against pathogens causing diseases of the respiratory tract. This study aimed to establish the clinical breakpoint (CBP) of cefquinome against H. parasuis and to monitor the resistance change. Referring to the minimum inhibitory concentration (MIC) distribution of cefquinome against 131 H. parasuis isolates, the MIC50 and MIC90 were determined to be 0.125 and 1 μg/mL, respectively. And the epidemiological cutoff (ECOFF) value was 1 μg/mL. HPS42 was selected as a representative strain for the pharmacodynamic (PD) experiment, pharmacokinetic (PK) experiment and clinical experiments. The PK/PD index values, area under concentration-time curve (AUC)/MIC, of the bacteriostatic, bactericidal, and bacterial elimination effects were 23, 41, and 51 h, respectively. The PK/PD cutoff was calculated as 0.125 μg/mL by Monte Carlo simulation (MCS), and the clinical cutoff was 0.25−4 μg/mL by WindoW. Combing these three values, the CBP of cefquinome against H. parasuis was found to be 1 μg/mL. In conclusion, this was the first study to integrate various cutoffs to establish the CBP in the laboratory. It is helpful to distinguish wild type H. parasuis and reduce the probability of treatment failure.

Exposure to Retinoic Acids in Non-Pregnant Women Following High Vitamin A Intake with a Liver Meal

2005 ◽  
Vol 75 (3) ◽  
pp. 187-194 ◽  
Author(s):  
Hartmann ◽  
Brørs ◽  
Bock ◽  
Blomhoff ◽  
Bausch ◽  
...  
Keyword(s):  
Plasma Concentration ◽  
Vitamin A ◽  
Safety Concern ◽  
Peak Plasma ◽  
Plasma Concentrations ◽  
Pregnant Female ◽  
Time Curve ◽  
High Vitamin ◽  
Concentration Time ◽  
Plasma Concentration Time Curve

Animal liver is a rich source of vitamin A. Due to retinoic acid (RA) metabolites, vitamin A has a teratogenic potential and women are generally advised to avoid or to limit the consumption of liver during pregnancy. In a recent study in non-pregnant female volunteers following single and repeated doses of up to 30,000 IU/day of vitamin A as a supplement, the plasma concentration time curve of all-trans RA acid showed a diurnal-like profile. But, the overall exposure (AUC24h) remained essentially unaltered whereas AUC24h increased linearly with dose for 13-cis and 13-cis-4-oxo RA. The current study in non-pregnant female volunteers showed that a single high vitamin A intake with a liver meal (up to 120,000 IU) exhibited a similar diurnal-like plasma concentration time curve for all-trans RA and its overall exposure remained also unaltered, despite a temporary two-fold increase in peak plasma concentration. Concentrations of 13-cis and 13-cis-4-oxo RA increased several-fold after a liver meal, and exposure (AUC24h) increased three- to five-fold. Pooling our results with data in the literature revealed a linear relation between the mean AUC24h of 13-cis and 13-cis-4-oxo RA and vitamin A intake with liver. Metabolism to all-trans RA of vitamin A with liver seems not to be of safety concern. However, the observed increase of plasma concentrations and the dose-dependent increase in exposure to 13-cis and 13-cis-4-oxo RA support the current safety recommendations on vitamin A intake and suggest that women should be cautious regarding their consumption of liver-containing meals during pregnancy.

scholarly journals Development of a Population Pharmacokinetic Model for Parecoxib and Its Active Metabolite Valdecoxib after Parenteral Parecoxib Administration in Children

2012 ◽  
Vol 116 (5) ◽  
pp. 1124-1133 ◽  
Author(s):  
Bruce Hullett ◽  
Sam Salman ◽  
Sean J. O'Halloran ◽  
Deborah Peirce ◽  
Kylie Davies ◽  
...  
Keyword(s):  
Active Metabolite ◽  
Pharmacokinetic Model ◽  
Inhibitory Concentration ◽  
Prediction Interval ◽  
Cyclooxygenase 2 ◽  
Pharmacokinetic Parameters ◽  
Population Pharmacokinetic ◽  
Time Curve ◽  
Concentration Time

Background Parecoxib is a cyclooxygenase-2 selective inhibitor used in management of postoperative pain in adults. This study aimed to provide pediatric pharmacokinetic information for parecoxib and its active metabolite valdecoxib. Methods Thirty-eight children undergoing surgery received parecoxib (1 mg/kg IV to a maximum of 40 mg) at induction of anesthesia, and plasma samples were collected for drug measurement. Population pharmacokinetic parameters were estimated using nonlinear mixed effects modeling. Area under the valdecoxib concentration-time curve and time above cyclooxygenase-2 in vitro 50% inhibitory concentration for free valdecoxib were simulated. Results A three-compartment model best represented parecoxib disposition, whereas one compartment was adequate for valdecoxib. Age was linearly correlated with parecoxib clearance (5.0% increase/yr). There was a sigmoid relationship between age and both valdecoxib clearance and distribution volume. Time to 50% maturation was 87 weeks postmenstrual age for both. In simulations using allometric-based doses the 90% prediction interval of valdecoxib concentration-time curve in children 2-12.7 yr included the mean for adults given 40 mg parecoxib IV. Simulated free valdecoxib plasma concentration remained above the in vitro 50% inhibitory concentrations for more than 12 h. In children younger than 2 yr, a dose reduction is likely required due to ongoing metabolic maturation. Conclusions The final pharmacokinetic model gave a robust representation of parecoxib and valdecoxib disposition. Area under the valdecoxib concentration-time curve was similar to that in adults (40 mg), and simulated free valdecoxib concentration was above the cyclooxygenase-2 in vitro 50% inhibitory concentration for free valdecoxib for at least 12 h.

Methotrexate pharmacokinetics following administration of recombinant carboxypeptidase-G2 in rhesus monkeys.

1992 ◽  
Vol 10 (8) ◽  
pp. 1359-1364 ◽  
Author(s):  
P C Adamson ◽  
F M Balis ◽  
C L McCully ◽  
K S Godwin ◽  
D G Poplack
Keyword(s):  
Plasma Concentration ◽  
Rhesus Monkeys ◽  
Alternative Form ◽  
High Dose ◽  
Time Curve ◽  
Carboxypeptidase G2 ◽  
Concentration Time ◽  
Bacterial Enzyme ◽  
Plasma Pharmacokinetics ◽  
Plasma Concentration Time Curve

PURPOSE Carboxypeptidase-G2 (CPDG2) is a bacterial enzyme that rapidly hydrolyzes methotrexate (MTX) into inactive metabolites. As an alternative form of rescue after high-dose MTX (HDMTX), CPDG2 has more potential advantages than standard leucovorin (LV) rescue. In this study, the plasma pharmacokinetics of MTX with and without CPDG2 were evaluated in adult rhesus monkeys. MATERIALS AND METHODS The plasma pharmacokinetics of MTX were determined in groups of animals that had received a 300-mg/m2 loading dose of MTX followed by a 60-mg/m2/h infusion during an 18-hour period. One group received CPDG2 at the end of the infusion, and the other group served as a control. Two additional animals with high titers of anti-CPDG2 antibody also were studied. RESULTS During infusion, the steady-state MTX plasma concentration was 11.3 +/- 4.8 mumol/L. Without CPDG2, the postinfusion plasma MTX concentration remained above 0.1 mumol/L for more than 6 hours. After the administration of 50 U/kg of CPDG2, plasma MTX concentrations decreased to nontoxic levels (less than 0.05 mumol/L) within 30 minutes. The initial half-life (t1/2 alpha) of MTX decreased from 5.8 +/- 2.1 minutes to 0.7 +/- 0.02 minutes after enzyme administration. The postinfusion area under the plasma concentration time curve of MTX was 301 +/- 171 mumol/L/min without CPDG2 compared with 19.6 +/- 6.1 mumol/L/min with CPDG2. The immunogenicity studies performed indicated that although animals developed anti-CPDG2 antibodies, none of them manifested allergic symptoms. The effectiveness of CPDG2 was diminished but not eliminated in animals with high titers of anti-CPDG2 antibody. CONCLUSIONS CPDG2 is capable of rapidly decreasing plasma MTX concentrations to nontoxic levels. The administration of CPDG2 seems safe, well tolerated, and it may be useful as an alternative to LV rescue.

Phase I and Pharmacokinetic Study of Temozolomide on a Daily-for-5-Days Schedule in Patients With Advanced Solid Malignancies

1999 ◽  
Vol 17 (8) ◽  
pp. 2604-2604 ◽  
Author(s):  
Lisa A. Hammond ◽  
John R. Eckardt ◽  
Sharyn D. Baker ◽  
S. Gail Eckhardt ◽  
Margaret Dugan ◽  
...  
Keyword(s):  
Oral Dose ◽  
Single Oral Dose ◽  
Hematologic Toxicity ◽  
Targeted Therapeutics ◽  
Time Curve ◽  
Concentration Time ◽  
Solid Malignancies ◽  
Cumulative Rate ◽  
Heavily Pretreated ◽  
Higher Doses

PURPOSE: To determine the principal toxicities, characterize the pharmacokinetics (PKs) and pharmacodynamics (PDs) of temozolomide (TMZ) on a daily-for-5-days schedule, and recommend a dose for subsequent disease-directed studies in both minimally pretreated (MP) and heavily pretreated (HP) patients. PATIENTS AND METHODS: Patients received TMZ as a single oral dose daily for 5 consecutive days every 28 days. TMZ doses were escalated from 100 to 150, and 150 to 200 mg/m2/d in separate cohorts of MP and HP patients. PK plasma was sampled on days 1 and 5. TMZ concentrations were analyzed and pertinent PK parameters were related to the principal toxicities of TMZ in PD analyses. RESULTS: Twenty-four patients were treated with 85 courses of TMZ. Thrombocytopenia and neutropenia were the principal dose-limiting toxicities (DLTs) of TMZ on this schedule. The cumulative rate of severe myelosuppressive effects was unacceptably high at TMZ doses exceeding 150 mg/m2/d in both MP and HP patients. TMZ was absorbed rapidly with maximum concentrations achieved in 0.90 hours, on average, and elimination was rapid, with a half-life and systemic clearance rate (ClS/F) averaging 1.8 hours and 115 mL/min/m2, respectively. When clearance was normalized to body-surface area (BSA), interpatient variability in ClS/F was reduced from 20% to 13% on day 1 and from 16% to 10% on day 5. Patients who experienced DLT had significantly higher maximum drug concentration (median 16 v 9.5 μg/mL, P = .0084) and area under the concentration-time curve (median 36 v 23 μg-h/mL, P = .0019) values on day 5. CONCLUSION: Prior myelosuppressive therapy was not a determinant of toxicity. TMZ 150 mg/m2/d administered as a single oral dose daily for 5 days every 4 weeks is well tolerated by MP and HP patients, with higher doses resulting in unacceptably high rates of severe hematologic toxicity. TMZ doses should be individualized according to BSA rather than use of a prespecified oral dose for all individuals. TMZ is an optimal agent to develop in combination with other cytotoxic, biologic, and targeted therapeutics for patients with relevant malignancies.

Pharmacokinetics of an immunomodulating dose of levamisole in weaned pigs

2013 ◽  
Vol 61 (3) ◽  
pp. 376-382
Author(s):  
Jelena Šuran ◽  
Dubravka Flajs ◽  
Maja Peraica ◽  
Andreja Prevendar Crnić ◽  
Marcela Šperanda ◽  
...  
Keyword(s):  
Plasma Concentration ◽  
Area Under The Curve ◽  
Maximum Plasma ◽  
Weaned Pigs ◽  
Time Curve ◽  
Treatment Groups ◽  
Parallel Design ◽  
Concentration Time ◽  
Plasma Concentration Time Curve ◽  
Crossbred Pigs

Levamisole has been shown to stimulate the immune response in immunocompromised humans and animals. However, its use as an adjuvant in immunocompromised weaned pigs prone to colibacillosis has only been experimentally tested but not yet officially approved. Therefore, the aim of these studies was to study the pharmacokinetics (PK) of an immunomodulating dose of levamisole in weaned pigs. For that purpose, 20 weaned crossbred pigs were divided into two treatment groups. In this parallel-design study, a single dose of levamisole (2.5 mg/kg body weight) was administered by the intramuscular (i.m.) or oral (p.o.) route. Statistically significant differences between the i.m. and p.o. routes in terminal beta rate constant (β), maximum plasma concentration (Cmax), area under the curve (AUC) for plasma concentration-time curve from time zero to infinity (AUC0-inf), area under the plasma concentration-time curve from time 0 to the last quantifiable time point (AUC0-t) were determined. Further research is needed to establish a relationship between the PK and the immunomodulating effect of levamisole in pigs.

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