Search results for "kinetics"
showing 10 items of 2224 documents
Atenolol interaction with aspirin, allopurinol, and ampicillin.
1983
Atenolol kinetics were investigated in six healthy subjects after 100 mg orally, as monotherapy a 6-day treatment began 48 hr later. After a therapy-free interval of 4 wk, the same subjects received the same dose of atenolol with 1 gm ampicillin, 500 mg aspirin, and with 300 mg allopurinol. Allopurinol and aspirin did not substantially alter the kinetics of atenolol. After a single oral dose of 100 mg atenolol combined with 1 gm ampicillin, the bioavailability of atenolol was reduced to 36 +/- 5% compared to 60 +/- 8% after monotherapy. During long-term treatment with atenolol and ampicillin the bioavailability of atenolol fell to 24% (P less than 0.01). Mean peak plasma levels were lowered…
Expanded gentamicin volume of distribution in critically ill adult patients receiving total parenteral nutrition
1995
Aminoglycoside antibiotics distribute into the extracellular fluid compartment and are eliminated by the kidney via glomerular filtration. Malnutrition and total parenteral nutrition influence the fluid and electrolyte status of the patient, and cause organ changes. The purpose of this clinical study was to characterize the kinetic behaviour of gentamicin in the parenterally fed critically ill adult patient. Eighty-six critically ill adult patients treated with gentamicin for severe Gram-negative infections were enrolled in the study (mean +/- SD): age, 60 +/- 14 years; weight, 69.4 +/- 10.2 kg; height, 163 +/- 10 cm; 22 females and 64 males. Four study groups were defined (2 x 2): total pa…
Biomechanical analysis of different starting strategies utilized during cross-country skiing starts
2016
The present study was designed to analyse and compare the kinetics and kinematics associated with three different starting strategies during classic cross-country ski racing. Inside a ski tunnel, 12 elite male skiers performed three sets of three 38 m starts. Each set included one start using: double poling only (DP), diagonal stride only (DIA) and freely chosen (FREE) (i.e. where subjects used the strategy or combination of strategies they felt was fastest) in random order. The first 18 m was performed on a series of force plates that measured horizontal and vertical forces followed by 20 m of a standard snow track. Additionally, cycle characteristics and joint angles were measured. DIA an…
Relationship between rheological properties, in vitro release and in vivo equivalency of topical formulations of diclofenac.
2019
Determination of bioequivalence remains a challenge in generic topical drug development. To support pharmacokinetic studies, strategies to demonstrate microstructure sameness of the products being compared include in vitro evaluations, such as the comparison of rheological properties, droplet size and in vitro release rates. Nevertheless, defining the appropriate acceptance range to consider equivalence between test and reference formulation is complex. To shed more light into this issue, in vitro release and rheological properties were compared to in vivo bioequivalence data (systemic blood measurements within a clinical trial) after topical application of a single dose. Test and reference…
Pharmacokinetic analysis of the interaction between dicoumarol and tolbutamide in man
1976
The effect of repeated administration of tolbutamide on the elimination and anticoagulant action of a single oral dose of dicoumarol 600 mg was studied in four healthy male subjects using a crossover design. In all subjects the plasma concentration of dicoumarol in the postabsorptive phase was lower during concomitant tolbutamide treatment. However, the subjects differed with respect to the elimination kinetics of dicoumarol and the effect of tolbutamide on some of the measured pharmacokinetic paramaters. In two subjects dicoumarol was eliminated by apparent first-order kinetics. Tolbutamide led to a pronounced increase in the elimination rate and a shift in the plasma concentration-respons…
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…
Inward currents in primary nociceptive neurons of the rat and pain sensations in humans elicited by infrared diode laser pulses
2002
Radiant heat is often used to study nociception in vivo. We now used infrared radiation generated by a diode laser stimulator (wavelength 980 nm) to investigate transduction mechanisms for noxious heat stimuli in acutely dissociated dorsal root ganglion (DRG) neurons of rats in vitro. The laser stimulator offered the unique opportunity to test whether the same stimuli also elicit pain sensations in humans. A specific heat-induced current (I(heat)) was elicited in six of 13 small DRG neurons (diameteror =30 microm) tested in the whole-cell configuration of the patch-clamp mode. Current responses in the seven heat-insensitive neurons were within the range explainable by the temperature depend…
Kinetic and electromyographic analysis of single repetition constant and variable resistance leg press actions
2010
During a multi-joint leg press action, maximal force capabilities increase with increasing knee angle. In typical resistance exercises, constant resistance is used, which does not stress the neuromuscular system at large knee angles. The purpose of this study was to compare constant and variable resistance settings using a range of contraction loads and velocities. Nine healthy, untrained males performed single contractions using four different resistance settings (constant resistance, two settings that increased resistance at large knee angles and one setting that reduced resistance at large knee angles). Single contractions using 40%, 60%, and 80% of one repetition maximum with both stead…
Pharmacokinetics and bioavailability of benperidol in schizophrenic patients after intravenous and two different kinds of oral application
1994
Pharmacokinetics and bioavailability of benperidol were determined in 13 schizophrenic patients after acute administration of 6 mg benperidol as an intravenous (i.v.) bolus injection, orally as liquid, and orally as tablets using a partially randomized cross-over design. Drug plasma levels were determined by high performance liquid chromatography with electrochemical detection and subjected to model independent pharmacokinetic analyses. After i.v. dosing the geometric means (mean-g) were 3.2 min for the distribution half-life, 5.80 h for the elimination half-life (t1/2 beta), 4.21 l/kg for the distribution volume, 7.50 h for the mean residence time (MRT), and 0.50 l/(h*kg) for the clearance…