Search results for "Absorption"
showing 10 items of 2701 documents
Inhibition of Protein S by Autoantibodies in Patients with Acquired Protein S Deficiency
1996
SummaryThis study was undertaken to analyze antibodies to protein S (PS) in patients with an acquired PS deficiency. Plasma from symptomatic patients with acquired (n = 14) or congenital (n = 10) PS deficiency and 10 healthy donors was screened for PS antibodies by immunoblotting and for anti-phospholipid antibodies. PS antibodies (IgG) were detected in five of the patients with acquired PS deficiency. These antibodies belonged to the G1 and G4 immunoglobulin subclasses. IgG fractions from the same 5 patients were shown to inhibit PS activity. The inhibition of PS activity by the 5 IgG fractions was shown to be time-and dose-dependent and was abolished following incubation with purified PS,…
Bioavailability and pharmacokinetic model for ritonavir in the rat.
2007
The aim of this study is to investigate in vivo the oral bioavailability of ritonavir and to evaluate the pharmacokinetic model that best describes the plasma concentration behavior after oral and intravenous administration. Male Wistar rats were intravenously administered at 3 mg dose of pure ritonavir and oral administered at 4.6 +/- 2.5 mg of diluted Norvir. Blood samples were taken by means of the jugular vein for a 24 h period of time. An analytical high-performance liquid chromatography (HPLC) technique was developed in order to quantify ritonavir plasma concentrations. A nonlinear modeling approach was used to estimate the pharmacokinetic parameters of interest. Results showed that a…
Ezetimibe/simvastatin 10/20 mg versus simvastatin 40 mg in coronary heart disease patients
2010
BACKGROUND: Reducing low-density lipoprotein cholesterol (LDL-C) is the primary goal of therapy in patients with hypercholesterolemia and coronary heart disease (CHD). METHODS: This double blind placebo-controlled study enrolled patients 18 to 75 years of age with primary hypercholesterolemia and establishedCHDwhowere taking a stable daily dose of simvastatin 20 mg. Patients were randomized to ezetimibe/simvastatin 10/20 mg (eze/simva; n 5 56) or simvastatin 40 mg (simva; n 5 56) for 6 weeks. Percent change from baseline in LDL-C, total cholesterol, high-density lipoprotein cholesterol (HDL-C), and triglycerides were assessed by use of the Student t test. The percent of patients achieving L…
Wistar rat skin as surrogate for human skin in nortriptyline hydrochloride patch studies
2009
Six different matrices were prepared containing nortriptyline hydrochloride (NTH) with hydroxypropyl-methyl-cellulose as polymer. A mixture of transdermal enhancers was included as part of the vehicle. Diffusion studies were carried out through Wistar rat full thickness skin using Franz cells. They were compared with previously determined human heat separated epidermis in order to test if this animal can be used as model for in vivo assays. A linear correlation was obtained between NTH diffusion coefficients through both skin types (r2=0.996).
Targeting metabolomics analysis of the sunscreen agent 2-ethylhexyl 4-(N,N-dimethylamino)benzoate in human urine by automated on-line solid-phase ext…
2011
The in vivo metabolism of the xenobiotic agent 2-ethylhexyl 4-(N,N-dimethylamino)benzoate (EDP), a UV filter commonly used in sunscreen cosmetic products, was studied by targeting metabolomics analysis in human urine. The metabolomic study involved the use of urine from male and female volunteers before and after application of an EDP-containing sunscreen cosmetic. The metabolism of EDP in urine was studied by using the triple quadrupole detector in a combination of Precursor Ion Scanning and Neutral Loss Scanning modes, with and without enzymatic hydrolysis. Detected metabolites were subsequently confirmed as glucuronide conjugates of 4-(N,N-dimethylamino)benzoic acid and 4-(N-methylamino)…
Characteristics of l-carnitine import into heart cells
2007
Abstract l -carnitine is an essential cofactor for the transport of fatty acids across the mitochondrial membranes. l -carnitine can be provided by food products or biosynthesized in the liver. After intestinal absorption or hepatic biosynthesis, l -carnitine is transferred to organs whose metabolism is dependent upon fatty acid oxidation, such as the skeletal muscle and the heart. The intracellular transport of l -carnitine into the cell requires specific transporters and today, several of these have been characterized. Most of them belong to the solute carrier family. Heart is one of the major target for carnitine transport and use, however basic properties of carnitine uptake by heart ce…
Intestinal transport of cefuroxime axetil in rats: absorption and hydrolysis processes.
2002
Studies were performed using three cefuroxime axetil solutions (11.8, 118 and 200 microM) in three selected intestinal segments and one cefuroxime axetil solution (118 microM) in colon of anaesthetized rats. First-order absorption rate pseudoconstants, k(ap) and effective permeability coefficients, P(eff), were calculated in each set. Absorption of cefuroxime axetil can apparently be described as a carrier-mediated transport, which obeys Michaelis-Menten and first order kinetics in the proximal segment of the small intestine and a passive diffusion mechanism in the mean and distal segments. The absorption kinetic parameters for cefuroxime axetil were obtained: Vm=0.613 (0.440) microM min-1;…
Controlled Iontophoretic Delivery in Vitro and in Vivo of ARN14140—A Multitarget Compound for Alzheimer’s Disease
2019
ARN14140 is a galantamine-memantine conjugate that acts upon both cholinergic and glutamatergic pathways for better management of Alzheimer's disease. Poor oral bioavailability and pharmacokinetics meant that earlier preclinical in vivo studies employed intracerebroventricular injection to administer ARN14140 directly to the brain. The aim of the present study was to evaluate the feasibility of using constant current transdermal iontophoresis for the noninvasive systemic delivery of ARN14140 and to quantify the amounts present in the blood and the brain. Preliminary experiments in vitro were performed using porcine skin and validated with human skin. Cumulative ARN14140 permeation across th…
Fruit and Vegetable Consumption is Inversely Associated with Plasma Saturated Fatty Acids at Baseline in Predimed Plus Trial
2021
I.D.-L. is supported by the [FI_B 00256] from the FI-AGAUR Research Fellowship Program, Generalitat de Catalunya and M.M.-M is supported by the FPU17/00513 grant. a.-H. is supported by the [CD17/00122] grant and S.K.N. is supported by a Canadian Institutes of Health Research (CIHR) Fellowship. We also thank all the volunteers for their participation in and the personnel for their contribution to the PREDIMED-Plus trial. This research was funded by CiCYT [AGL2016-75329-R] and CIBEROBN from the Instituto de Salud Carlos III, ISCIII from the Ministerio de Ciencia, Innovacion y Universidades, (AEI/FEDER, UE), Generalitat de Catalunya (GC) [2017SGR196]. The PREDIMED-Plus trial was supported by t…
Kinetic study of acamprosate absorption in rat small intestine.
2000
Acamprosate (calcium bis acetyl-homotaurine), a homotaurine derivative, a structural analogue of gamma-aminobutyric acid (GABA) and an upper homologue of taurine, is a relatively new drug used to prevent relapse in weaned alcoholics. When administered orally as enteric-coated tablets at relatively high doses, this drug has a bioavailability of about 11%; however, the intestinal absorption mechanism has not been studied in depth. The present study was therefore planned to characterize the intestinal transport of acamprosate in the rat and the effect of chronic alcohol treatment on this process, quantifying its kinetic parameters and investigating possible inhibitors. Using an in vitro techni…