Search results for "absorption"
showing 10 items of 2701 documents
Influence of green and black tea on folic acid pharmacokinetics in healthy volunteers: potential risk of diminished folic acid bioavailability
2008
Previous in vitro studies using Caco-2 cell monolayers suggested a possible interaction between green and black tea and folic acid at the level of intestinal absorption. The main purpose of the present study was to investigate a possible pharmacokinetic interaction between tea and folic acid in healthy volunteers. In an open-labeled randomized cross-over study, the pharmacokinetic interaction between tea and folic acid (0.4 mg and 5 mg) was investigated in healthy volunteers. Water was used as the reference drink. Subjects ingested 0.4 mg folic acid tablets with water, green or black tea (0.3 g extract/250 ml) or 5 mg folic acid tablets with water or green tea (0.3 g extract/250 ml). Blood …
The role of cytochrome P450 2D6 in the metabolism of moclobemide.
1996
The metabolic fate of moclobemide (Ro 11-1163), a new reversible and selective inhibitor of monoamine oxidase type A (MAO-A), has been assessed in a pilot study in 2 debrisoquine poor metabolizers (PM) and 4 extensive metabolizers (EM) after multiple oral dosings of moclobemide with and without co-medication of dextromethorphan. Absorption and disposition parameters were not different between PM and EM. Concurrent application of dextromethorphan, a selective substrate of CYP2D6, did not affect the pharmacokinetics of moclobemide. These results indicate that the cytochromal isoenzyme CYP2D6 does not play a major role in the metabolic degradation of moclobemide. Limited CYP2D6 activities beca…
Justification of Biowaiver for Carbamazepine, a Low Soluble High Permeable Compound, in Solid Dosage Forms Based on IVIVC and Gastrointestinal Simula…
2009
The aim of the present study was to use gastrointestinal simulation technology and in vitro-in vivo correlation (IVIVC) as tools to investigate a possible extension of biowaiver criteria to BCS class II drugs using carbamazepine (CBZ) as a candidate compound. Gastrointestinal simulation based on the advanced compartmental absorption and transit model implemented in GastroPlus was used. Actual in vitro and in vivo data generated in CBZ bioequivalence studies were used for correlation purposes. The simulated plasma profile, based on the CBZ physicochemical and pharmacokinetic properties, was almost identical with that observed in vivo. Parameter sensitivity analysis (PSA) indicated that the p…
A novel technique for intraduodenal administration of drug suspensions/solutions with concurrent pH monitoring applied to ibuprofen formulations
2019
Characterization of dissolution of solid suspended drug particles in vivo is important for developing biopredictive in vitro tests. Therefore, methods to gain deeper insights into particle dissolution in vivo are needed. The soft Bioperm intubation method, a well established tool for investigation of permeability, absorption, metabolism, and drug interactions at predefined locations in the gastroinstinal tract, was modified. The novel intubation method involved pump-controlled infusion of pharmaceutical suspensions as well as simultaneous pH monitoring. This technique was used in a proof of concept study in healthy humans. Plasma sampling and non-compartmental analysis allowed comparison of…
Biomonitoring in wearers of permethrin impregnated battle dress uniforms in Afghanistan and Germany.
2013
Objectives To analyse differences in uptake of the insecticide permethrin in wearers of non-impregnated and permethrin impregnated battle dress uniforms (BDU) in Afghanistan and Germany. Methods In two separate studies, in April 2003–January 2004 (study I, n=549) and in February–April 2005 (study II, n=195), healthy female and male members of the German Federal Armed Forces were equipped with permethrin impregnated BDU (two sub-cohorts in Germany and one in Afghanistan) while members equipped with non-impregnated uniforms served as a control group. Human biomonitoring was conducted before, during and after wearing the uniforms by measuring permethrin metabolites in urine samples via GC–MS. …
Determination of acetylcholine, nitrostigmine and acetylcholinesterase activity in four patients with severe nitrostigmine (E 605 forte) intoxication.
1974
Concentrations of acetylcholine and nitrostigmine as well as acetylcholinesterase activity were determined in 4 patients with severe nitrostigmine intoxication. In the acute phase of the intoxication, acetylcholine levels up to 36 and 55 ng/ml were found in blood plasma and cerebrospinal fluid, respectively. At the same time no activity of acetylcholinesterase in plasma and erythrocytes was detected. Acetylcholinesterase activity gradually recovered at the end of the second week. In the first 3 days after the ingestion plasma nitrostigmine concentrations ranged from 409 to 86 ng/ml. At the end of the third week nitrostigmine was still found in a concentration of about 1 ng/ml plasma. Redist…
External and internal exposure of wine growers spraying methyl parathion.
2005
Organophosphates, used in agriculture, are readily absorbed through the skin. We investigated the relationship between dermal and inhalative methyl parathion exposure and the plasma levels. Twenty-three healthy wine growers sprayed the insecticide for 50 min. Fluorescent brilliant sulfoflavin was added to the spraying fluids and filter papers were fixed on the subjects. The filter papers were used to evaluate the amount of brilliant sulfoflavine on the unprotected skin fluorometrically. Inhalative exposure was measured with personal air sampler. Plasma concentrations of methyl parathion and its metabolite methyl paraoxon were determined with gas chromatography. Cholinesterase activity in se…
Pharmacokinetics of triamterene after i.v. administration to man: determination of bioavailability.
1983
With a new formulation, which made intravenous infusion of triamterene (TA) possible, plasma levels and urinary excretion rates of TA and its main metabolite (OH-TA-ester) were measured in a randomized, cross-over trial in 6 healthy volunteers given triamterene 10 mg i.v. and 50 mg p.o. TA and OH-TA-ester were determined by densitometric measurement of native fluorescence after thin layer chromatography. Distribution volumes of the central compartment of TA and OH-TA-ester were 1.49 l/kg and 0.11 l/kg, respectively. Terminal half-lives were 255 min for TA and 188 min for OH-TA-ester after i.v. administration. For TA total plasma clearance was 4.5 l/min and renal plasma clearance 0.22 l/kg. …
Mortality in patients with coeliac disease and their relatives: a cohort study.
2001
Summary Background Although previous studies have shown increased mortality in patients with coeliac disease and their relatives, no data are available in relation to different patterns of clinical presentation. We assessed mortality in patients with coeliac disease and their first-degree relatives. Methods We enrolled, in a prospective cohort study, 1072 adult patients with coeliac disease consecutively diagnosed in 11 gastroenterology units between 1962 and 1994, and their 3384 first-degree relatives. We compared the number of deaths up to 1998 with expected deaths and expressed the comparison as standardised mortality ratio (SMR) and relative survival ratio. Findings 53 coeliac patients …
Resting metabolic rate and postabsorptive substrate oxidation in morbidly obese subjects before and after massive weight loss
1996
OBJECTIVE: To investigate the changes of resting metabolic rate (RMR) and postabsorptive oxidation of carbohydrates (CHO), lipids (LIP) and proteins (PT) in morbidly obese subjects after long-term stable massive weight reduction. DESIGN: Longitudinal, intervention study of a bilio-pancreatic by-pass. SUBJECTS: Ten (Four men, six women) obese subjects (BMI: 53.7 ± 2.1 kg/m2, men, nine women) control subjects (BMI: 21.4 ± 1.0 kg/m2). MEASUREMENTS: RMR and substrates oxidation (indirect calorimetry), body composition (bioelectrical impedance), plasma concentrations of glucose, FFA, insulin and thyroid hormones before (T0, prior to surgery), during (T1: 1-3 months, and T2: 9-16 months following…