Prediction of Drug Terminal Half-Life and Terminal Volume of Distribution After Intravenous Dosing Based on Drug Clearance, Steady-State Volume of Distribution, and Physiological Parameters of the Body

2013 ◽  
Vol 102 (2) ◽  
pp. 761-771 ◽  
Author(s):  
Leonid M. Berezhkovskiy
2001 ◽  
Vol 20 (12) ◽  
pp. 601-609 ◽  
Author(s):  
D Newton ◽  
R J Talbot ◽  
N D Priest

A healthy male volunteer received an intravenous injection of 207Bi as citrate. Levels of the tracer in blood and in excretion samples, and its retention and distribution within the body, were investigated by appropriate radioactivity measurements. Levels in blood fell very rapidly, with only 1% of the injection remaining at 7 h and only ca. 0.1% at 18 days. There was rapid initial excretion, with 55% lost during the first 47 h, principally in urine; however, longer-term losses were much slower and 0.6% remained in the body at 924 days, when the contemporary rate of loss implied a half-life of 1.9 years. Integration of the retention pattern suggested that steady exposure to bismuth compounds could lead ultimately to a body content of 24 times the daily systemic uptake. The largest organ deposit was in the liver, which after 3 days contained ca. 60% of the contemporary whole body content, consistent with reports of hepatotoxicity. These findings differ markedly from the metabolic model for bismuth proposed by the International Commission on Radiological Protection, which envisages a terminal half-life in the body of only 5 days and kidney as the site of highest deposition.


1998 ◽  
Vol 79 (01) ◽  
pp. 169-176 ◽  
Author(s):  
Nishit Modi ◽  
Sherron Bullens ◽  
Cheryl Pater ◽  
Michael Lipari ◽  
Kirk Robarge ◽  
...  

SummaryRo 44-3888 is a potent and selective antagonist of GP IIb/IIIa. Following IV administration to rhesus monkeys, the (mean ± SD.) clear ance, volume of distribution and terminal half-life of Ro 44-3888 were 4.4 ± 1.8 ml/min/kg, 0.8 ± 0.4 l/kg and 2.5 ± 0.8 h respectively. Oral administration of Ro 48-3657 (1 mg/kg), a doubly protected prodrug form, produced peak concentrations of Ro 44-3888 (152 ± 51 ng/ml), 4.2 ± 2.2 h after dosing. Terminal half-life and estimated bioavailabil ity were 5.1 ± 1.6 h and 33 ± 6% respectively. No effect on blood pressure, heart rate or platelet counts were seen. Adenosine diphosohate (ADP) induced platelet aggregation (PA) and cutaneous bleeding times (CBT) were determined prior to and after the last of 8 daily oral administrations of Ro 48-3657 (0.25 or 0.5 mg/kg) to eight rhesus monkeys. Peak and trough plasma concentrations were proportional to dose and steady state was achieved after the second administration. Inhibition of PA and prolongation of CBT were concentration dependent. The ex vivo IC50 (82 nM) for ADP-mediated PA correlated with a value (58 nM) determined in vitro. The CBT response curve was displaced to the right of the PA curve. CBT was prolonged to ≥25 min when levels of Ro 44-3888 exceeded 190 nM and PA was >90% inhibited. Therefore, in rhesus monkeys, Ro 48-3657 is reproducibly absorbed and converted to its active form, is well tolerated, and has a concentration-dependent effect on PA and CBT. These properties make Ro 48-3657 an attractive candidate for evaluation in patients at high risk for arterial thrombosis.


Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 1597-1597 ◽  
Author(s):  
Jorge Cortes ◽  
James M. Foran ◽  
Marcel P. Devetten ◽  
Francis J. Giles ◽  
Joyce James ◽  
...  

Abstract Introduction: Activating mutations in FLT3 are present in a significant fraction of acute myeloid leukemia (AML) cases. Patients with FLT3 mutations have a significantly worse prognosis than patients with wild type FLT3, suggesting that the activated kinase is a driver of the disease. AC220 is a novel class III receptor tyrosine kinase (RTK) inhibitor. It has highly potent activity against FLT3 and is highly selective for wild type and mutant FLT3 and other class III RTKs, including KIT, CSF1R/FMS, RET and PDGFR. AC220 is currently in a phase I clinical study for relapsed or refractory AML patients. Human pharmacokinetic (PK) data from early cohorts are presented along with the preclinical profile in support of the rationale for the clinical evaluation of AC220 in AML. Methods: Cellular efficacy of AC220 was evaluated in the FLT3-dependent human leukemia cell line MV4;11. This cell line was implanted in a mouse xenograft model, which was used to assess animal efficacy. In preclinical studies, pharmacokinetics were determined in rats and dogs. The clinical study is a phase I, first-in-man, multi-center, open label, sequential dose escalation study. AC220 is administered once daily as an oral solution for 14 days with a starting dose of 12 mg. At least three centers in the U.S. enrolled AML patients into three-patient cohorts. Results: AC220 inhibits proliferation of MV4;11 cells with subnanomolar potency (IC50 = 0.3 nM). In the mouse MV4;11 xenograft model, tumor regression is observed at 3 mg/kg (9 mg/m2, p.o., qd), and tumor growth inhibition at 1 mg/kg (3 mg/m2, p.o., qd). The terminal half-life is 5.7 hours in rats and 5.9 hours in dogs. In the clinical study, one male and two female patients were enrolled into cohort 1. The weight range for these patients is 77.9 to 101.27 kg. The average plasma concentrations at the 12 mg dose are 11.2 ng/mL at day 1, 37.9 ng/mL at day 8 and 42.9 ng/mL (0.06 μM) at steady state (by day 15), with an apparent terminal half-life of at least 2.8 days. Inter-patient variability of steady state plasma concentrations within the 3-patient cohort is low. Conclusions: At the human dose of 12 mg, AC220 is well tolerated and absorbed. It has a long terminal half-life and the inter-patient pharmacokinetic variability is low. Steady state is predicted to be reached within 8 to 14 days with minor peaks and troughs. There is a strong correlation between efficacy in the mouse model and AC220 plasma levels (adjusted for plasma protein binding) relative to potency in the MV4;11 cell-based assay. At the human dose of 12 mg (average 5.2 mg/m2), the plasma level of AC220 at steady state (0.06 μM, when adjusted for plasma protein binding) is approximately twofold higher than the MV4;11 cell IC50. Continued exploration in patients is warranted to determine the role of AC220 in the treatment of AML.


2020 ◽  
Author(s):  
Ziran Li ◽  
Chenyu Wang ◽  
Xiao Zhu ◽  
Zheng Jiao

Background: Levetiracetam has been widely used as a treatment option for different types of epilepsy in both adults and children. Because of its large between-subject variability, several population pharmacokinetic studies have been performed to identify its pharmacokinetic covariates, and thus facilitate individualised therapy. Objective: The aim of this review was to provide a synopsis for population pharmacokinetic studies of levetiracetam and explore identified influencing covariates. Methods: We systematically searched PubMed and Embase databases from inception to June 30, 2020. The information on study designs, target population, model characteristics, and identified covariates were summarised. Moreover, the pharmacokinetic profiles were compared among neonates, children, and adults. Results: A total of 14 studies were included, among which two involved neonates, four involved children, two involved both children and adults, and six involved only adults. The median value of apparent clearance for children (0.074 [range: 0.038 to 0.079] L/h/kg) was higher than that for adults (0.054 [range: 0.039 to 0.061] L/h/kg). Body weight was found to influence the apparent clearance and volume of distribution significantly, whereas renal function influenced the clearance. Likewise, co-administration with enzyme-inducing antiepileptic drugs (such as carbamazepine and phenytoin) increased the drug clearance by 9 to 22%, whereas coadministration with valproate acid decreased it by 18.8%. Conclusion: Levetiracetam dose regimen is dependent on the body size and renal function of patients. Further studies are needed to evaluate levetiracetam pharmacokinetics in neonates and pregnant women.


DICP ◽  
1989 ◽  
Vol 23 (6) ◽  
pp. 468-472 ◽  
Author(s):  
Richard G. D'Angio ◽  
Peter R. Gwilt

Drugs administered at fixed intervals or by continuous infusion will accumulate in the body until steady state is achieved. The time to a given percentage of the eventual steady-state concentration has previously been considered to be dependent only on the elimination half-life. This is incorrect. Although the rate of drug accumulation in the body is dependent only on the elimination half-life, the time to a given percentage of steady state is dependent on both the elimination half-life of the drug and the initial concentration. This paper presents the mathematical proof of this concept, computer simulations demonstrating the use of these equations, and nomograms for use in clinical practice. The use of this method allows serum drug concentrations to be evaluated earlier than previously predicted after changes in the dosing rate.


2009 ◽  
Vol 53 (7) ◽  
pp. 3024-3029 ◽  
Author(s):  
Elias Gebru ◽  
Joong-Su Lee ◽  
Zhi-Qiang Chang ◽  
Mi-Hyun Hwang ◽  
Henrique Cheng ◽  
...  

ABSTRACT The pharmacokinetics (PK) and pharmacodynamics (PD) of orbifloxacin were studied in beagle dogs after intravenous (i.v.) and intramuscular (i.m.) administration at a dose of 2.5 mg/kg body weight. An absolute bioavailability of 100.1% ± 4.76%, a terminal half-life of 4.23 ± 0.2 h and 3.95 ± 0.15 h after i.v. and i.m. administration, a steady-state volume of distribution of 1.61 ± 0.13 liters/kg, and clearance of 0.31 ± 0.03 liters/h/kg were observed. Orbifloxacin showed rapid, concentration-dependent killing against the Escherichia coli, Staphylococcus aureus, Staphylococcus intermedius, and Proteus mirabilis clinical isolates. Computations based on PK-PD analysis indicated that the recommended dose is unlikely to be clinically effective against some strains like S. intermedius. Therefore, a higher dose of orbifloxacin would be worthy of consideration for treatment of certain bacterial infections in dogs.


1992 ◽  
Vol 26 (1) ◽  
pp. 8-10 ◽  
Author(s):  
David E. Nix ◽  
J. Michael Spivey ◽  
Allyn Norman ◽  
Jerome J. Schentag

OBJECTIVE: To assess the pharmacokinetics and tolerance of ciprofloxacin after the administration of single intravenous doses of 200, 300, and 400 mg. DESIGN: Double-blind, three-period, randomized, crossover trial. SETTING: Private, university-affiliated, hospital-based, clinical research center. PATIENTS: Normal healthy male volunteers, 18–40 years of age. INTERVENTIONS: Subjects received 200-, 300-, and 400-mg single intravenous doses of ciprofloxacin via 30-minute infusions in random sequence. MAIN OUTCOME MEASURES: Serum ciprofloxacin concentrations were determined by HPLC after each dose and the results were used to derive pharmacokinetic parameters. Tolerance was assessed by reported and observed adverse events, urine microscopic examinations for crystals, and examination of intravenous infusion sites. RESULTS: The mean area under the time curve (AUC) values displayed linearity with respect to the administered dose. No statistical differences were observed in total body clearance, steady-state volume of distribution, or elimination half-life with respect to dose administered. The mean total body clearance, steady-state volume of distribution, or elimination half-life ranged from 36 to 41 L/h, 146 to 169 L, and 3.5 to 3.7 h for the 200-, 300-, and 400-mg doses, respectively. Adverse effects, including venous irritation (four subjects) and crystalluria (two subjects), were mild and did not require withdrawal of any subject from the study. CONCLUSIONS: Intravenous ciprofloxacin in doses ranging from 200 to 400 mg demonstrated linear pharmacokinetics. These single doses were well tolerated, although cases of transient venous irritation and crystalluria were observed.


2011 ◽  
Vol 2011 ◽  
pp. 1-5
Author(s):  
Harshad B. Patel ◽  
Shailesh K. Mody ◽  
Hitesh B. Patel ◽  
Vipul A. Patel ◽  
Urvesh D. Patel

The present study was carried out to investigate disposition kinetics of moxifloxacin following single-dose intravenous (i.v.), intramuscular (i.m.), and subcutaneous (s.c.) administration at a dose rate of 5 mg/kg of body weight (b.wt.) in goats. Plasma samples collected after treatments were analyzed for drug concentration using high-performance liquid chromatography (HPLC). After i.v. administration, distribution of the drug was rapid and wide as reflected by high steady-state volume of distribution. Drug elimination was relatively faster with a total body clearance of 0.59±0.03 L/h/kg. Following i.m. injection, the drug has shown the rapid and near-to-complete absorption with bioavailability of 98.20±3.96 per cent. The maximum plasma drug concentration (Cmax) of 1.21±0.04 μg/mL was attained at 1 h (Tmax). The drug was widely distributed as reflected by high apparent volume of distribution. The elimination half-life (t1/2β) of the drug was 6.26±0.08  h. Following s.c. administration, the drug was rapidly absorbed (Cmax: 1.16±0.02 μg/mL; tmax: 1 h) and slowly eliminated from the body. The elimination half-life and total body clearance (ClB) were 5.61±0.10 h and 0.60±0.03 L/h/kg, respectively. The bioavailability of moxifloxacin following s.c. administration was 90.44±3.96 per cent.


Animals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2468
Author(s):  
Ji-Hoon Lee ◽  
Ga Won Kim ◽  
Mun-Gyeong Kwon ◽  
Jung Soo Seo

The objective of this study was to demonstrate the pharmacokinetic–pharmacodynamic profile, bioavailability, and withdrawal time of tylosin tartrate (TT) administered to olive flounder via intramuscular (IM, 10 or 20 mg/kg, n = 240) and intravascular (IV, 10 mg/kg, n = 90) injections. Serum concentrations of tylosin were determined using a validated liquid chromatography-tandem mass spectrometry method. According to the non-compartmental analysis, the bioavailability of TT was 87%. After the IV injection, the terminal half-life, total body clearance, volume of distribution, and mean residence time of TT were 21.07 h, 0.07 L/kg/h, 2.15 L/kg, and 16.39 h, respectively. Rapid absorption (Tmax 0.25 h), prolonged action (terminal half-life, 33.96 and 26.04 h; MRT, 43.66 and 33.09 h), and linear dose–response relationship (AUC0-inf, 123.55 and 246.05 µg/mL*h) were monitored following 10 and 20 mg/kg IM injection. The withdrawal time of TT from muscle (water temperature, 22 °C) was 9.84 days, rounded up to 10 days (220 degree days). Large Cmax/MIC90, AUC0-inf/MIC90, and T > MIC90 values were obtained for Streptococcus isolates and these PK/PD indices satisfied the criteria required for efficacy evaluation. This study lays a foundation for the optimal use of TT and provides valuable information for establishing therapeutic regimens.


2014 ◽  
Vol 17 (1) ◽  
pp. 99-103 ◽  
Author(s):  
S. Yohannes ◽  
Md. Akil Hossain ◽  
J.Y. Kim ◽  
S.J. Lee ◽  
D.M. Kwak ◽  
...  

Abstract The association between physiologically dependent pharmacokinetic parameters (CLB, T1/2β, Vdss) of marbofloxacin and body weight was studied in eight animal species based on allometric equation Y = aWb, where ‘Y’ is the pharmacokinetic parameter, ‘W’ is body weight, ‘a’ is allometric coefficient (intercept) and ‘b’ is the exponent that describes relation between pharmacokinetic parameter and body weight. The body clearance of marbofloxacin has shown significant (P<0.0001) relation with size (Bwt) in various animal species. However, half-life and volume of distribution were not in association with body weight. Although half-life and volume of distribution were not in a good correlation with body weight, statistically significant association between the body clearance and body weight suggests validity of allometric scaling for predicting pharmacokinetic parameters of marbofloxacin in animal species that have not been studied yet. However further study considering large sample size and other parameters influencing pharmacokinetics of marbofloxacin is recommended.


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