Search results for "Pharmacokinetics"
showing 10 items of 458 documents
Metabolic Clearance of the Antioxidant Ascorbic Acid in Surgical Patients1
2005
Background A reduction of plasma ascorbic acid concentration in the post-operative period has been well documented and is associated with an increase in post-operative complications. The underlying reason for the decreased concentration of ascorbic acid in the plasma is not clear. However, only an increased post-operative requirement for ascorbic acid would justify a substitution. Therefore, we investigated the pre-operative and post-operative metabolic clearance of ascorbic acid. Materials and Methods We calculated the metabolic clearance subsequent to intravenous bolus injection of 6 mg ascorbic acid/kg body weight in 15 patients before and after they underwent major maxillofacial surgery…
Retention–property relationships of anticonvulsant drugs by biopartitioning micellar chromatography
2001
Epilepsy may be considered as a group of disorders with only one thing in common: the fact that recurrent anomalous electrochemical phenomena appear in the central nervous system. Different classes of drugs are included under the generic term of anticonvulsant drugs. All of them work by decreasing discharge propagation in different ways. Biopartitioning micellar chromatography (BMC) is a mode of reversed-phase liquid chromatography, which can be used as an in vitro system to model the biopartitioning process of drugs when there are no active processes. In this paper, relationships between the BMC retention data of anticonvulsant drugs, their pharmacokinetics (oral absorption, protein bindin…
Physiological pharmacokinetic model for ceftazidime disposition in the rat and its application to prediction of plasma concentrations in humans
1993
Abstract A physiological pharmacokinetic model for the disposition of ceftazidime in the rat was developed. The model is composed of 10 compartments which represent most of the organs and tissues of the body. Ceftazidime concentration-time profiles in the organs and tissues represented in the model were simulated and compared with the observed concentration-time data after i.v. administration of 5 and 20 mg of antibiotic. The model gave an acceptable description of the observed data. The steady-state volume of distribution and total clearance of ceftazidime in healthy humans predicted from data obtained in the rat (0.21 l/kg and 113 ml/min, respectively) were similar to the values reported …
Retention pharmacokinetic and pharmacodynamic parameter relationships of antihistamine drugs using biopartitioning micellar chromatography
2001
Abstract Antihistamines are drugs which act by competitive inhibition of the H1 or H2 histamine receptors. Little has been known about their clinical pharmacokinetics and biological responses until the last few years. In this paper, we propose quantitative retention–activity relationship, QRAR, models based on the retention data of antihistamines in a biopartitioning micellar chromatography (BMC) system using a Brij35 mobile phase for describing pharmacokinetic parameters such as half-life and volume of distribution, or the pharmacodynamic parameters, therapeutic plasma levels, lethal doses and drug-receptor dissociation constant. The predictive ability of these models is statistically vali…
Pharmacokinetics of the cannabinoid receptor ligand [18 F]MK-9470 in the rat brain - Evaluation of models using microPET
2018
PURPOSE The positron emission tomography ligand [18 F]MK-9470 is an inverse agonist that binds reversibly and with high affinity to the cannabinoid type 1 receptor. Due to its slow brain kinetics, care is required in the definition of its dissociation rates from the receptor. The goal of this study was to investigate pharmacokinetic analysis methods using an arterial input function. METHODS Five Sprague-Dawley rats received injections of 13 to 25 MBq of [18 F]MK-9470 and were scanned over a period of 90 min. Arterial blood samples were collected throughout the scan. Data were analyzed using four different compartmental models: a reversible one-tissue model, reversible two tissue models with…
Pharmacokinetic/Pharmacodynamic Model of Neutropenia in Real-Life Palbociclib-Treated Patients
2021
Palbociclib is an oral CDK4/6 inhibitor indicated in HR+/HER2- advanced or metastatic breast cancer in combination with hormonotherapy. Its main toxicity is neutropenia. The aim of our study was to describe the kinetics of circulating neutrophils from real-life palbociclib-treated patients. A population pharmacokinetic (popPK) model was first constructed to describe palbociclib pharmacokinetic (PK). Individual PK parameters obtained were then used in the pharmacokinetic/pharmacodynamic (PK/PD) model to depict the relation between palbociclib concentrations and absolute neutrophil counts (ANC). The models were built with a population of 143 patients. Palbociclib samples were routinely collec…
A Contribution Concerning the Unsettled Problem of Intrasplenic Microcirculation
1973
From morphological studies it is well known that the vascular bed of the spleen consists of at least two different compartments. Figure one schematically shows how the splenic microcirculation can be subdivided. One compartment corresponds to the white pulp (pathways number 1 and 2), the other compartment to the red pulp, for which the existance of either an open or a closed type of terminal vascular bed is discussed. Futhermore there are references that the microcirculation in the red pulp is not homogeneous but composed of both types, as illustrated by the pathways marked by number 3 and 4.
Cerebrospinal fluid pharmacokinetics of ceftaroline in neurosurgical patients with external ventricular drain
2018
International audience; Background: Due to its antibacterial properties ceftaroline could be attractive for the treatment of bacterial postneurosurgicalmeningitis. However only few data are available concerning its meningeal concentrations. The aim of this studywas to investigate ceftaroline cerebrospinal fluid (CSF) pharmacokinetics (PK) in intensive care unit (ICU) patients with anexternal ventricular drain (EVD).Materials/methods: Patients received a single 600 mg dose of ceftaroline as a one-hour intravenous infusion . Blood and CSFsamples were collected before and 0.5, 1, 3, 6, 12 and 24 hours after the end of the infusion. Concentrations were assayed inplasma and CSF by LC-MS/MS. A tw…
PET Studies of d-Methamphetamine Pharmacokinetics in Primates: Comparison with l-Methamphetamine and (—)-Cocaine
2007
The methamphetamine molecule has a chiral center and exists as 2 enantiomers, d-methamphetamine (the more active enantiomer) and l-methamphetamine (the less active enantiomer). d-Methamphetamine is associated with more intense stimulant effects and higher abuse liability. The objective of this study was to measure the pharmacokinetics of d-methamphetamine for comparison with both l-methamphetamine and (-)-cocaine in the baboon brain and peripheral organs and to assess the saturability and pharmacologic specificity of binding.d- and l-methamphetamine and (-)-cocaine were labeled with (11)C via alkylation of the norprecursors with (11)C-methyl iodide using literature methods. Six different ba…
Intravenous Use of Methadone: Efficacy and Safety
2013
Parenteral methadone could be helpful in specific conditions, particularly in unstable conditions of when the oral route is unavailable. Intravenous methadone should be the preferred parenteral route, due to concerns about the local toxicity of subcutaneous route. This chapter assesses aspects regarding the pharmacokinetic issues, the clinical use, the problems associated with the use of intravenous methadone for chronic pain, as well as the perioperative use of intravenous methadone.