Search results for "absorption."
showing 10 items of 2682 documents
Gastric relaxation induced by glucagon-like peptide-2 in mice fed a high-fat diet or fasted.
2011
Glucagon-like peptide-2 (GLP-2) is a nutrient-responsive gut hormone that increases the intestinal absorption. Exogenous GLP-2 also induces gastric fundus relaxation with possible implications for emptying rate or feeling of satiety. GLP-2 actions are mediated by GLP-2 receptor (GLP-2R), located on enteric neurons and myofibroblasts in murine gastrointestinal tract. Because it is not known whether changes in the endogenous GLP-2R levels occur in different nutritional states, we examined the GLP-2R gene and protein expression in gastric fundus from standard diet (STD)-fed, 12-h and 24-h fasted and re-fed, or high-fat diet (HFD)-fed mice and we analyzed the mechanical responses to exogenous G…
Modelling intestinal absorption of salbutamol sulphate in rats
2005
The objective was to develop a semiphysiological population pharmacokinetic model that describes the complex salbutamol sulphate absorption in rat small intestine. In situ techniques were used to characterize the salbutamol sulphate absorption at different concentrations (range: 0.15-18 mM). Salbutamol sulphate at concentration of 0.29 mM was administered in presence of verapamil (10 and 20 mM), grapefruit juice and sodium azide (NaN3) (0.3, 3 and 6 mM). Different pharmacokinetic models were fitted to the dataset using NONMEM. Parametric and non-parametric bootstrap analyses were employed as internal model evaluation techniques. The validated model suggested instantaneous equilibrium betwee…
Genetic Polymorphisms and Individualized Tacrolimus Dosing
2010
Background. Genetic polymorphisms of metabolism enzymes or intestinal drug transporters may affect pharmacokinetic responses to immunosuppressive drugs in renal transplant recipients. We sought to identify the frequency of genetic polymorphisms and their importance for individualization of tacrolimus doses. Patients and Methods. We performed an observational study in 35 renal transplant recipients treated with tacrolimus, mycophenolate mofetil, and corticosteroids. Tacrolimus concentrations were determined by immunoanalysis (IMx method; Abbott Diagnostics, Abbott Park, Ill), on 11 blood samples per patient during the first 6 weeks after renal transplantation. For each patient, we calculated…
Low bioavailability of amoxicillin in rats as a consequence of presystemic degradation in the intestine.
1994
Several studies have been carried out to elucidate the causes of the low oral bioavailability of amoxicillin in rats. The hepatic first-pass effect of the antibiotic was estimated by comparing the area under the plasma drug concentration-versus-time curve from time zero to infinity (AUC0-infinity) obtained after injecting the drug into a mesenteric vein with the AUC0-infinity value obtained after injecting the drug into the jugular vein of conscious rats. No hepatic first-pass effect was detected. The bioavailability of amoxicillin after intraduodenal administration was only 51%, and the fraction of the dose remaining in the intestine at the end of the experiment was 4.5%. This was far less…
N-Succinyl-chitosan systems for 5-aminosalicylic acid colon delivery: In vivo study with TNBS-induced colitis model in rats
2011
5-Aminosalicylic acid (5-ASA) loaded N-Succinyl-chitosan (SucCH) microparticle and freeze-dried system were prepared as potential delivery systems to the colon. Physicochemical characterization and in vitro release and swelling studies were previously assessed and showed that the two formulations appeared to be good candidates to deliver the drug to the colon. In this work the effectiveness of these two systems in the treatment of inflammatory bowel disease was evaluated. In vitro mucoadhesive studies showed excellent mucoadhesive properties of both the systems to the inflamed colonic mucosa. Experimental colitis was induced by rectal instillation of 2,4,6-trinitrobenzene sulfonic acid (TNB…
Cholesterol and saturated fat intake determine the effect of polymorphisms at ABCG5/ABCG8 genes on lipid levels in children.
2006
Purpose: Analysis of mutations in genes of the cholesterol metabolic pathway has not completely explained the interindividual variability of blood cholesterol concentrations attributed to gene–nutrient interactions. Thus, we analyzed polymorphisms in the ABCG5 and ABCG8 genes, involved in the regulation of intestinal cholesterol absorption, with special interest in a potential interaction with diet to determine lipid levels. Methods: The polymorphisms ABCG5 C1950G (Gln604Glu) and ABCG8 C1895T (Ala640Val) were determined by polymerase chain reaction and restriction analysis in 1227 healthy school children, aged 6 to 8 years. Results: No significant differences were found in blood lipid level…
Comparison of segmental-dependent permeability in human and in situ perfusion model in rat.
2017
Abstract Nowadays, alternative methods have been developed to predict intestinal permeability values in human as in vitro, in situ or ex vivo methods. They were developed by the necessity to avoid the problems of the human permeability experiments. However, determination of human permeability is needed to properly validate the alternative methods. For this reason, recently, Dahlgren et al. published an indirect method based on a deconvolution technique to estimate the human permeability in different gastrointestinal segments (jejunum, ileum and colon). Therefore, the objective of this research was to demonstrate that Doluisio technique is a useful method to predict the human permeability in…
Influence of a Commercial Lead Apron on Patient Skin Dose Delivered During Oral and Maxillofacial Examinations under Cone Beam Computed Tomography (C…
2017
The purpose of this paper is to investigate the impact of a commercial lead apron on patient skin dose delivered during maxillofacial CBCT in five critical regions by means of solid-state-dosimetry. Five anatomical regions (thyroid gland, left and right breast, gonads, back of the phantom torso) in an adult female anthropomorphic phantom were selected for dose measurement by means of the highly sensitive solid-state dosimeter QUART didoSVM. Ten repeated single exposures were assessed for each patient body region for a total of five commercial CBCT devices with and without a lead apron present. Shielded and non-shielded exposures were compared under the paired Wilcoxon test, with absolute an…
Pharmacokinetics and bioavailability of diclofenac in the rat.
1991
Diclofenac sodium is a widely used drug with interesting absorption and disposition features when administered to laboratory animals. The present study was undertaken to assess the pharmacokinetics of the drug after iv and gastrointestinal dosing to rats. Renal excretion of unchanged drug was negligible, but biliary excretion of the drug (unchanged and conjugated) was detected in bile duct-cannulated rats; it accounted for 27.2 and 31.2% of the total dose following iv and intraduodenal administration, respectively. Most of the drug excreted in the bile was conjugated diclofenac; unchanged drug accounted for only 4.7 and 5.4% of total diclofenac excreted in the bile after iv and intraduodena…
The influence of active secretion processes on intestinal absorption of salbutamol in the rat.
2001
Abstract Salbutamol was perfused in the small intestine of rat using a standard rat gut ‘in situ’ preparation: (1) in inhibitor-free solution at seven different concentrations (0.15, 0.29, 1.20, 5.0, 9.0, 13.0 and 18.0 mM); (2) at a 0.29 mM concentration – thought to be close to the allometric dose in man – in the presence of a non-specific enzyme inhibitor, sodium azide (0.3, 3.0 and 6.0 mM); and (3) at 0.29 mM in the presence of a selective secretion inhibitor, verapamil (10.0 and 20.0 mM). In free solution, the mixed-order rate constants, k ′ a , of salbutamol increase as the solute concentration increases until an apparent asymptotic value is reached. This could be due to the saturation…