Lachrymal Concentration of Norfloxacin after a Single Ocular Instillation in Humans

1994 ◽  
Vol 4 (2) ◽  
pp. 102-104 ◽  
Author(s):  
F. Drago ◽  
E. De Bernardis
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Half Life ◽  
High Performance ◽  
Area Under The Curve ◽  
Elimination Half Life ◽  
Elimination Half

Lachrymal concentrations of the fluoroquinolone norfloxacin were studied in 30 subjects (aged 24-35 years) after a single ocular instillation (0.3% solution, 50 ul) in comparison with ofloxacin instilled at the same dose. Lachrymal levels were measured by high performance liquid chromatography (HPLC). Lachrymal peak levels were comparable 5 min after instillation but norfloxacin appeared to have a longer elimination half-life than ofloxacin. The AUC (area under the curve) for norfloxacin was therefore higher than for ofloxacin (35.9 and 10.7 mg* min/ml, respectively). These data suggest that norfloxacin may have higher corneal retention than ofloxacin, so this antibiotic may be indicated in superficial infections dependent on fluoroquinolone-sensitive bacteria.

Doxorubicin clearance in the obese.

1988 ◽  
Vol 6 (8) ◽  
pp. 1321-1327 ◽  
Author(s):  
K A Rodvold ◽  
D A Rushing ◽  
D A Tewksbury
Keyword(s):  
Body Weight ◽  
Half Life ◽  
High Performance ◽  
Area Under The Curve ◽  
Ideal Body Weight ◽  
Apparent Volume ◽  
Volume Of Distribution ◽  
Obese Patients ◽  
Elimination Half Life ◽  
Elimination Half

A study was carried out to examine the effect, if any, of obesity on doxorubicin pharmacokinetics. Body weight was found to be significantly related to doxorubicin clearance (r = -.75; P less than .001) and elimination half-life (r = .62; P = .003). Thus, the contribution of obesity on pharmacokinetics of antineoplastic agents should be taken into consideration in the analysis of clinical data with respect to toxicity and tumor response. Twenty-one patients were studied with their first course of doxorubicin (50 to 70 mg/m2) administered as a 60-minute intravenous (IV) infusion. Patients were divided into three groups on the basis of percentage of ideal body weight (IBW): normal (less than 115% IBW), mildly obese (115% to 130% IBW), and obese (greater than 130% IBW). Blood samples were collected up to 48 hours after the infusion and analyzed for doxorubicin and its metabolite, doxorubicinol, by high performance liquid chromatography. Doxorubicin area under the curve (AUC) was greater in obese than in normal patients (2,209 v 1,190 ng h/mL; P less than .05), yielding correspondingly reduced systemic clearance of the agent in obese patients (891 v 1,569 mL/min; P less than .001). The mean elimination half-life (T1/2) was 20.4 hours in the obese patients and 13.0 hours in the normal patients. The apparent volume of distribution (Vss) was not significantly different among the three groups of patients, indicating that the prolonged T1/2 in the obese patients is due to the reduction in clearance. The AUC and T1/2 of doxorubicinol were similar among all patient groups.

Purification of a 166mHo solution by successive high-performance liquid chromatography and gravitational chromatography for half-life determination

2014 ◽  
Vol 302 (1) ◽  
pp. 289-295 ◽  
Author(s):  
Florence Guéguen ◽  
Hélène Isnard ◽  
Karsten Kossert ◽  
Carole Bresson ◽  
Céline Caussignac ◽  
...  
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Half Life ◽  
High Performance

scholarly journals Decreasing half-life of dieldrin in egg yolk following a single oral administration of aldrin to laying hens

2001 ◽  
Vol 49 (4) ◽  
pp. 465-472
Author(s):  
N. Furusawa
Keyword(s):  
Body Weight ◽  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Single Dose ◽  
Half Life ◽  
High Performance ◽  
Laying Hens ◽  
Egg Yolk ◽  
Single Oral Administration ◽  
Low Levels

Laying hens were treated orally with a single dose of aldrin (AD) 1 mg/kg body weight. Concentrations (μg/g) of AD or its epoxide (= dieldrin, DD) in the yolk of eggs laid for 21 days after AD treatment were determined by normalphase high-performance liquid chromatography. The limits of determination were 0.02 μg/g for AD and 0.03 μg/g for DD, respectively. After AD treatment, although the low levels of AD (mean 0.02–0.03 μg/g) were observed only during a three-day period (from 4th to 6th days), DD (mean 0.15 μg/g) was found already on the 2nd day, indicating that the epoxidation of AD to DD in the hen’s body is rapid. The highest level of DD (mean 0.40 μg/g) was detected on the 6th day, and then DD levels decreased slowly and were detected up to the 21st day. In this decreasing phase, the half-life of DD in the yolk was estimated to be 25.6 days with a 95% confidence interval from 22.7 to 29.4 days.

scholarly journals DISSIPAÇÃO DO HERBICIDA (R,S) HALOXIFOPE EM LATOSSOLO TROPICAL

2004 ◽  
Vol 14 ◽  
Author(s):  
MARCUS BARIFOUSE MATALLO ◽  
LUIZ CARLOS LUCHINI ◽  
FLAVIO MARTINS GARCIA BLANCO ◽  
TEREZINHA BONANHO PERES ◽  
DANIEL GUSTAVO RICHENA
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Half Life ◽  
High Performance ◽  
Methanolic Extract ◽  
Tropical Soil ◽  
Soil Samples ◽  
Ultra Sound ◽  
Previously Treated ◽  
Para Determinar

Com o objetivo de estudar o comportamento do herbicida (R,S)-haloxifope em solo tropical realizouse este trabalho para determinar sua dissipação num latossolo roxo eutrófico. Para isso, amostras de solo (em triplicata) foram previamente tratadas com haloxifope metil racêmico e incubadas a 25oC por 0, 6, 10 15, 30 e 60 dias. Após cada período de incubação as amostras foram submetidas a extração em ultra-som, purificadas com diclorometano, evaporadas em rotavapor e ressuspendidas em metanol. O extrato metanólico foi analisado por Cromatografia a Líquido de Alta Eficiência (CLAE). Os dados cinéticos mostraram meia-vida inicial (t0½) de 7,38 dias, o que pode estar relacionado com a atividade microbiana de caráter enantiosseletivo no solo. (R,S)-HALOXYFOP DISSIPATION IN A TROPICAL LATOSOIL Abstract The aim of the work was to study the behavior of the herbicide (R,S)-haloxyfop in a tropical soil. This work was realized to determine its dissipitaion in an eutrophic purple latosoil. Three replicates of soil samples were previously treated with methyl racemic haloxyfop and incubated at 25ºC for 0, 6, 10, 15, 30 and 60 days. After each incubation period the samples were submited to ultra sound extraction, purified with dichoromethane, evaporated and ressuspended in methanol. The methanolic extract was analysed by High Performance Liquid Chromatography (HPLC). The kinetics data revealed initial half life (t01/2) of 7.38 days, which can probably be related to the microbial activity with enantioselective character in soil.

scholarly journals Herb-Drug Pharmacokinetic Interaction of a Traditional Chinese Medicine Jia-Wei-Xiao-Yao-San with 5-Fluorouracil in the Blood and Brain of Rat Using Microdialysis

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Meng-Hsuan Chiang ◽  
Li-Wen Chang ◽  
Ju-Wen Wang ◽  
Lie-Chwen Lin ◽  
Tung-Hu Tsai
Keyword(s):  
Chinese Medicine ◽  
Half Life ◽  
High Performance ◽  
Pharmacokinetic Interaction ◽  
Volume Of Distribution ◽  
Research Database ◽  
Elimination Half Life ◽  
Elimination Half ◽  
Drug Pharmacokinetic ◽  
The Brain

According to a survey from the National Health Insurance Research Database (NHIRD), Jia-Wei-Xiao-Yao-San (JWXYS) is the most popular Chinese medicine for cancer patients in Taiwan. 5-Fluorouracil (5-FU) is a general anticancer drug for the chemotherapy. To investigate the herb-drug interaction of JWXYS on pharmacokinetics of 5-FU, a microdialysis technique coupled with a high-performance liquid chromatography system was used to monitor 5-FU in rat blood and brain. Rats were divided into four parallel groups, one of which was treated with 5-FU (100 mg/kg, i.v.) alone and the remaining three groups were pretreated with a different dose of JWXYS (600, 1200, or 2400 mg/kg/day for 5 consecutive days) followed by a combination with 5-FU. This study demonstrates that 5-FU with JWXYS (600 mg/kg/day or 1200 mg/kg/day) has no significant effect on the pharmacokinetics of 5-FU in the blood and brain. However, JWXYS (2400 mg/kg/day) coadministered with 5-FU extends the elimination half-life and increases the volume of distribution of 5-FU in the blood. The elimination half-life of 5-FU in the brain for the pretreatment group with 2400 mg/kg/day of JWXYS is significantly longer than that for the group treated with 5-FU alone and also reduces the clearance. This study provides practical dosage information for clinical practice and proves the safety of 5-FU coadministered with JWXYS.

scholarly journals Determination of flumazenil in serum by liquid chromatography-mass spectrometry: Application to kinetics study in acute diazepam overdose

2016 ◽  
Vol 73 (2) ◽  
pp. 146-151
Author(s):  
Snezana Djordjevic ◽  
Jasmina Jovic-Stosic ◽  
Vesna Kilibarda ◽  
Zoran Segrt ◽  
Natasa Perkovic-Vukcevic
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Half Life ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Serum Samples ◽  
Elimination Half Life ◽  
Elimination Half ◽  
Limit Of Quantitation

Backgound/Aim. Flumazenil is benzodiazepine receptor antagonist. It has been studied for a various indications, including reversal of sedation after surgery or diagnostic procedures, awakening of comatose patients in benzodiazepine overdose, or for symptomatic treatment of hepatic encephalopathy. Some drugs, like theophylline, may prolong its elimination half-life. Considering the long half-life of diazepam and its metabolites, concomitant use of theophylline may reduce the need for repeated dosing of flumazenil in patients with acute diazepam poisoning. The aim of this study was to introduce a reliable and accurate method for determining the concentration of flumazenil after therapeutic application in patients with acute poisoning, and using that method to assess whether the kinetics of flumazenil change in the presence of aminophylline (combination of theophylline and ethylenediamine in a 2 : 1 ratio) applied as concomitant therapy. Methods. Blood samples from patients with acute diazepam poisoning that received flumazenil at the dose of 0.5 mg, or the same dose with 3 mg/kg of body weight of aminophylline, were collected 1, 3, 10, 30, 60, 120 and 240 min after its intravenous administration. Samples were prepared by solid-phase extraction on Oasis HLB cartridges with ethylacetate as extracting agens. Flumazenil was determined by liquid chromatography with mass spectrometry (LC-MS) in single ion monitoring mode at m/z 304. Separation of flumazenil from matrix compound was performed on Lichrospher RP-8 column using the mixture of acidic acetonitrile and 20 mM of ammonium acetate in water (55 : 45) as a mobile phase. Results. The applied analitycal method showed excellent recovery (94.65%). The obtained extracts were much cleaner than the extracts obtained by the same extractant in the process of liquid-liquid extraction. The limit of detection of the LC-MS method described in this paper was 0.5 ng/mL and the limit of quantitation was 1 ng/mL. In the patients treated with both flumazenil and aminophylline, the elimination constant for flumazenil was significantly lower and the elimination half-life was longer (p < 0.05) in comparison with the same parameters in the patients who received flumazenil alone. Conclusion. The applied LC-MS method for the determination of flumazenil in serum samples of patients with acute diazepam poisoning is rapid, sensitive, precise and specific. Concomitant use with theophylline significantly prolonged elimination of flumazenil during the treatment of acute poisonings with diazepam.

The Effect of Activated Charcoal on the Absorption and Elimination of Astemizole

1994 ◽  
Vol 13 (7) ◽  
pp. 502-505 ◽  
Author(s):  
Kari Laine ◽  
Kari T. Kivistö ◽  
Pertti J. Neuvonen
Keyword(s):  
Gastrointestinal Tract ◽  
Healthy Volunteers ◽  
Activated Charcoal ◽  
Half Life ◽  
Area Under The Curve ◽  
Elimination Half Life ◽  
The Third ◽  
Multiple Doses ◽  
Elimination Half

1 The effect of activated charcoal on the absorption and elimination of astemizole and its metabolites was studied in healthy volunteers. 2 Subjects were divided into three groups containing seven subjects each. One group received 30 mg of astemizole with water only (control) and another group with 25 g of activated charcoal. The third group received multiple doses (12 g) of charcoal from 6 h onwards twice daily for 8 days. The concentrations of astemizole and its metabolites in plasma were measured by radioimmunoassay for 192 h. 3 Activated charcoal, administered immediately after astemizole ingestion, reduced the absorption of astemizole by 85% (P<0.001). Multiple doses of activated charcoal, administered throughout the period of astemizole elimination, had no significant effect on the rate of elimination or the area under the curve from 0 to 192 h. 4 The absorption of astemizole from the gastrointestinal tract can be effectively prevented with activated charcoal. Because astemizole is rapidly absorbed, charcoal should be administered as soon as possible in acute astemizole poisoning. Multiple doses of charcoal do not seem to shorten the elimination half-life of astemizole.

Note. Caffeine Content and Dynamical Bitterness of Yerba Mate Ilex paraguariensis Infusions

2005 ◽  
Vol 11 (6) ◽  
pp. 401-407 ◽  
Author(s):  
A. M. Calviño ◽  
O. P. Tamasi ◽  
M. C. Ciappini
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Time Course ◽  
Total Duration ◽  
Area Under The Curve ◽  
Maximum Intensity ◽  
Ilex Paraguariensis ◽  
Yerba Mate ◽  
Caffeine Content

The infusion of yerba mate (YM) Ilex paraguariensis, with its typical bitterness, is traditionally consumed in South America as a mild stimulant beverage. Two types of YM, with sticks (YM-S) and without sticks (YM-L) and three brands for each type were evaluated for caffeine content and the time course of bitterness. The chemical analysis of the six YM infusions at 5% w/v made by high performance liquid chromatography (HPLC) showed that caffeine levels were higher for YM-L brands. The kinetic study of YM bitterness assessed by time-intensity (TI) curves revealed that the presence of sticks lowered maximum intensity, total duration and area under the curve of bitter perception.

scholarly journals Pharmacokinetics of Gatifloxacin and Interaction with an Antacid Containing Aluminum and Magnesium

1999 ◽  
Vol 43 (5) ◽  
pp. 1067-1071 ◽  
Author(s):  
Silke Lober ◽  
Susanne Ziege ◽  
Margot Rau ◽  
Gabriele Schreiber ◽  
Alain Mignot ◽  
...  
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Standard Deviation ◽  
Crossover Study ◽  
Magnesium Hydroxide ◽  
Peak Concentration ◽  
High Performance ◽  
Area Under The Curve ◽  
Optimal Time ◽  
Comparison Of The Results

ABSTRACT The pharmacokinetics of gatifloxacin (400 mg orally) and the influence of the antacid aluminum magnesium hydroxide (20 ml of Maalox 70) on the bioavailability of gatifloxacin in 24 healthy volunteers were assessed. In an open, randomized, six-period crossover study, the volunteers received either gatifloxacin alone (treatments A and D); aluminum magnesium hydroxide concomitant with gatifloxacin (treatment C); or aluminum magnesium hydroxide 2 h before (treatment B), 2 h after (treatment E), or 4 h after gatifloxacin administration (treatment F). Gatifloxacin concentrations were measured by a validated bioassay and high-performance liquid chromatography. Pharmacokinetics of a single 400-mg dose of gatifloxacin alone were characterized as follows (mean ± standard deviation): peak concentration (C max), 3.8 ± 0.5 (treatment A) and 3.4 ± 0.9 (treatment D) μg/ml; time toC max, 1.4 ± 0.8 (treatment A) and 1.7 ± 0.7 (treatment D) h; area under the curve from time zero to infinity (AUC0–∞), 33.5 ± 5.9 (treatment A) and 31.4 ± 3.4 (treatment D) μg · h/ml; urine recovery, (83 ± 6)% (treatment A) and (84 ± 8)% (treatment D). Comparison of the results obtained by bioassay showed a good correlation. Aluminum magnesium hydroxide administration 2 h before (treatment B) or concomitant with (treatment C) gatifloxacin decreased the C max by 45% (2.1 ± 1.2 μg/ml) or even 68% (1.2 ± 0.4 μg/ml) highly significantly (P < 0.01). AUC0–∞ was significantly reduced from 33.5 ± 5.9 to 19.4 ± 6.9 μg · h/ml (by 42%) or even to 11.9 ± 3.3 μg · h/ml (by 64%) (P < 0.01). If aluminum magnesium hydroxide was given 2 h after gatifloxacin (treatment E), there was no significant reduction of concentration in serum but AUC0–∞ was significantly reduced from 31.4 ± 3.4 to 25.9 ± 5.3 μg · h/ml (18%) (P < 0.01). Aluminum magnesium hydroxide given 4 h after gatifloxacin (treatment F) showed no influence on the gatifloxacin pharmacokinetics. Therefore, the optimal time between gatifloxacin application and the intake of an aluminum-containing antacid should be 4 h.

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