Search results for "kinetics"
showing 10 items of 2224 documents
Efecto de la administración concomitante de indometacina o ibuprofeno en la farmacocinética de amikacina en neonatos prematuros
2006
Objective: To evaluate whether the concomitant administration of ibuprofen or indomethacin plus amikacin may alter the latter drug's pharmacokinetic parameters, and hence amikacin plasma levels. Method: Retrospective cohort study performed by reviewing the medical records of premature children with persistent ductus arteriosus receiving amikacin and ibuprofen, or amikacin and indomethacin. They were divided up into three groups: group 1: treatment with amikacin went before indomethacin or ibuprofen; group 2: simultaneously treated with amikacin and indomethacin; group 3: simultaneously treated with amikacin and ibuprofen. Pharmacokinetic parameters, distribution volume, and amikacin clearan…
Purification of a nuclease from human serum.
1981
The purification procedure for a nuclease from human serum is described. It includes ammonium sulfate precipitation, chromatography on DEAE-Sephadex and on Sephacryl-S 200, and preparative electrophoresis. The enzyme, purified about 2000-fold, is homogeneous in a sodium dodecyl sulfate electrophoretic system, where it has a mol. wt of 78,000. The pH optimum lies around pH 6.5; it is a sugar-nonspecific endonuclease.
A 18F-labeled dibenzocyclooctyne (DBCO) derivative for copper-free click labeling of biomolecules
2016
The new prosthetic group 18F-TEG-DBCO (dibenzocyclooctyne) can be prepared within a total reaction time of 60 min including purification with an overall yield (n.d.c.) of 34 ± 5%. Copper-free click cycloadditions with an azido-cRGD, a folate-azide and two α-MSH analogue azido-peptides resulted in very high RCYs and fast reaction kinetics.
Increased bioavailability of oral melatonin after fluvoxamine coadministration*1
2000
Background Fluvoxamine, a selective serotonin reuptake inhibitor, is known to elevate melatonin serum concentrations. It has not been clear whether these effects might be attributed to an increased melatonin production or to an decreased elimination of melatonin. The latter hypothesis was tested by this study. Methods Five healthy male volunteers (one CYP2D6 poor metabolizer) received 5 mg melatonin either with or without coadministration of 50 mg fluvoxamine. Serum concentrations of melatonin and fluvoxamine were assessed from 0 to 28 hours after melatonin intake. Results Coadministration of fluvoxamine, on average, led to an 17-fold higher (P <.05) area under concentration–time curve (AUC…
Rewarding Properties of Testosterone in Intact Male Mice
2000
The present study examined the rewarding properties of 4-androsten-17β-ol-3-one testosterone in intact male mice using the conditioned place preference (CPP) technique. In Experiment 1, the pharmacokinetics of 0.8 and 1.2 mg/kg of testosterone were studied to determine the most appropriate temporal interval to test behavior. Additionally, the locomotor activity was recorded to control a possible interfering effect on CPP. The maximum testosterone concentration was registered at 45 min of administration, and no effects on activity were found. In Experiment 2, three groups of male OF-1 mice received four pairings of the least-preferred compartment with testosterone (0.8, 1, or 1.2 mg/kg, SC) …
Farmacocinética del metronidazol y la gentamicina en dosis única preoperatoria para profilaxis antibiótica quirúrgica en cirugía colorrectal
2008
Objective: To describe, in patients undergoing colorectal surgery (CRS), the pharmacokinetics of a single, prophylactic preoperative dose of 1,500 mg of metronidazole plus 240 mg gentamicin and measure its efficacy in accordance with the accepted pharmacodynamic and microbiological parameters. Method: Thirty-six patients undergoing CRS agreed to participate in the study. Three blood samples were taken from each. Cmax 15 minutes after finishing the infusion of the mixture, CfinIQ on finishing the surgery, and Cmin between 12 and 24 hours post-administration. The concentrations of metronidazole and gentamicin in each simple were measured and the pharmacokinetic parameters were estimated (dV- …
Monitorización de la vacomicina en administración intraperitoneal en pacientes sometidos a diálisis peritoneal continua ambulatoria
2012
Objective: To validate a pharmacokinetic model of the treatments with intraperitoneal vancomycin applied to patients on continuous ambulatory peritoneal dialysis with bacterial peritonitis. Methods: To carry out a prospective study divided in 2 cohorts: the first one including ten patients of 56 ± 14 years and 65 ± 5 kg, and the second one with 10 patients (12 episodes of peritonitis) aged 52 ± 13 years and 64 ± 8 kg. The treatment consists of administering and retaining for 6 h in the peritoneal cavity a solution containing 2 g of vancomycin and 1 g of ceftazidime into 2 l of ‘‘dialysis solution’’. After the antibiotic administration, blood samples were obtained at 4, 6, 8, 10, 24, 48 and …
Development of a nomogram for the estimation of long-term adherence to clozapine therapy using neutrophil fluorescence
2018
Aims: Previously, we have reported an association between clozapine use and elevated FL3 neutrophil fluorescence, a flow-cytometric parameter for cell viability. Here, we developed and evaluated a pharmacokinetic-pharmacodynamic model relating FL3-fluorescence to clozapine exposure and derived a nomogram for estimation of long-term adherence. Methods: Data from 27 patients initiating clozapine were analysed using nonlinear mixed effects modelling. A previously described pharmacokinetic model for clozapine was coupled to a FL3 fluorescence model. For this, an effect compartment with clozapine concentrations as input and a first order decay rate as output was linked with an Emax model to FL3-…
Dehydration of mildronate dihydrate: a study of structural transformations and kinetics
2014
The dehydration of mildronate dihydrate (3-(1,1,1-trimethylhydrazin-1-ium-2-yl)propionate dihydrate) was investigated by powder X-ray diffraction, thermal analysis, hot-stage microscopy, water sorption–desorption studies and dehydration kinetic studies. It was determined that mildronate dihydrate dehydrated in a single step, directly transforming into the anhydrous form. In order to understand the reasons for a one step dehydration mechanism, crystal structures of dihydrate, monohydrate and anhydrous forms were compared, proving the similarity of the dihydrate and anhydrous forms. In order to understand the reasons for molecule reorganization during dehydration, the energy of the anhydrous …
Crystal growth kinetics in deionised two-component colloidal suspensions
2007
We report first measurements of the crystal growth velocity in deionised two-component aqueous suspensions of charged polystyrene latex spheres. The size ratio was 1:1.3 and mixing ratios up to 18% of the larger particle were investigated. For the pure components limiting growth velocities of (V ∞,120 = 4.8 µm s−1 and V ∞,156 = 2.9 µm s−1) were observed. In the mixture v drops with increasing mixing ratio even below (V ∞,156) of the large minority component. Careful monitoring of the deionisation procedure excludes the explanation of enhanced ionic contamination. Alternatives based on the kinetics of particle attachment and the position of the phase boundary are discussed.