scholarly journals Compartmental Pharmacokinetics of the Antifungal Echinocandin Caspofungin (MK-0991) in Rabbits

2001 ◽  
Vol 45 (2) ◽  
pp. 596-600 ◽  
Author(s):  
Andreas H. Groll ◽  
Bryan M. Gullick ◽  
Ruta Petraitiene ◽  
Vidmantas Petraitis ◽  
Myrna Candelario ◽  
...  
Keyword(s):  
High Performance ◽  
Pharmacokinetic Model ◽  
Area Under The Curve ◽  
Apparent Volume ◽  
Volume Of Distribution ◽  
Pharmacokinetic Parameters ◽  
Chromatography Method ◽  
Opportunistic Fungi ◽  
The Mean ◽  
Liquid Chromatography Method

ABSTRACT The pharmacokinetics of the antifungal echinocandin-lipopeptide caspofungin (MK-0991) in plasma were studied in groups of three healthy rabbits after single and multiple daily intravenous administration of doses of 1, 3, and 6 mg/kg of body weight. Concentrations were measured by a validated high-performance liquid chromatography method and fitted into a three-compartment open pharmacokinetic model. Across the investigated dosage range, caspofungin displayed dose-independent pharmacokinetics. Following administration over 7 days, the mean peak concentration in plasma (C max) ± standard error of the mean increased from 16.01 ± 0.61 μg/ml at the 1-mg/kg dose to 105.52 ± 8.92 μg/ml at the 6-mg/kg dose; the mean area under the curve from 0 h to infinity rose from 13.15 ± 2.37 to 158.43 ± 15.58 μg · h/ml, respectively. The mean apparent volume of distribution at steady state (Vdss) was 0.299 ± 0.011 liter/kg at the 1-mg/kg dose and 0.351 ± 0.016 liter/kg at the 6-mg/kg dose (not significant [NS]). Clearance (CL) ranged from 0.086 ± 0.017 liter/kg/h at the 1-mg/kg dose to 0.043 ± 0.004 liter/kg/h at the 6-mg/kg dose (NS), and the mean terminal half-life was between 30 and 34 h (NS). Except for a trend towards an increasedVdss, there were no significant differences in pharmacokinetic parameters in comparison to those after single-dose administration. Caspofungin was well tolerated, displayed linear pharmacokinetics that fit into a three-compartment pharmacokinetic model, and achieved sustained concentrations in plasma that were multiple times in excess of reported MICs for susceptible opportunistic fungi.

scholarly journals Pharmacokinetics of Gentamicin C1, C1a, and C2 in Beagles after a Single Intravenous Dose

2000 ◽  
Vol 44 (6) ◽  
pp. 1443-1447 ◽  
Author(s):  
Nina Isoherranen ◽  
Eran Lavy ◽  
Stefan Soback
Keyword(s):  
High Performance ◽  
Plasma Concentrations ◽  
Volume Of Distribution ◽  
Pharmacokinetic Analysis ◽  
Time Data ◽  
Chromatography Method ◽  
The Mean ◽  
The Difference ◽  
Liquid Chromatography Method ◽  
Toxicological Significance

ABSTRACT The pharmacokinetics of gentamicin C1, C2, and C1a were studied in six beagles after administration of gentamicin at 4 mg/kg of body weight as a single intravenous bolus dose. Plasma concentrations of the gentamicin components were analyzed with a novel high-performance liquid chromatography method capable of identifying and quantifying each of the components. The pharmacokinetic analysis of the plasma concentration-versus-time data was performed using the noncompartmental approach. The results indicated significant differences in the pharmacokinetic characteristics between the gentamicin components C1, C1a, and C2. The mean residence times of gentamicin C1, C1a, and C2 were 81 ± 13, 84 ± 12, and 79 ± 13 min (mean ± standard deviation), respectively. The half-lives of the respective components were 64 ± 12, 66 ± 12 and 63 ± 12 min. Clearance (CL) of gentamicin C1, 4.62 ± 0.71 ml min−1 kg−1, was significantly higher (P = 0.0156) than CL of gentamicin C1a, 1.81 ± 0.26 ml min−1kg−1, and C2, 1.82 ± 0.25 ml min−1 kg−1. Similarly, the volume of distribution at steady state (V ss) of gentamicin C1, 0.36 ± 0.04 liter kg−1, was significantly higher (P = 0.0156) than the V ss of gentamicin C1a, 0.14 ± 0.01 liter kg−1, and C2, 0.15 ± 0.02 liter kg−1. Tissue binding was considered the most likely cause for the difference. The difference may have clinical and toxicological significance.

scholarly journals Penetration of ceftibuten into middle ear fluid.

1996 ◽  
Vol 40 (6) ◽  
pp. 1394-1396 ◽  
Author(s):  
C Lin ◽  
P Kumari ◽  
R J Perrotta ◽  
B E Reidenberg
Keyword(s):  
Middle Ear ◽  
Pediatric Patients ◽  
Acute Otitis Media ◽  
Area Under The Curve ◽  
Pharmacokinetic Parameters ◽  
Chromatography Method ◽  
Middle Ear Fluid ◽  
Liquid Chromatography Method ◽  
Oral Doses ◽  
Major Pathogens

The penetration of ceftibuten, an extended-spectrum oral cephalosporin, into middle ear fluid (MEF) was evaluated in pediatric patients during a course of daily oral doses of 9 mg/kg of body weight for 10 days. Plasma and MEF collected at 2, 4, 6, or 12 h after at least 3 days of dosing were analyzed for ceftibuten by a high-pressure liquid chromatography method, and the data were used to calculate pharmacokinetic parameters. Plasma and MEF had almost identical maximum concentrations (Cmax) of ceftibuten (14 micrograms/ml). These Cmax values in MEF during acute otitis media were well in excess of the MIC for 90% of the isolates of each of four major pathogens in this disease. The time to Cmax was longer in MEF (4 h) than in plasma (2 h). Excellent penetration (71%) of ceftibuten into MEF was observed on the basis of the area under the curve ratio (MEF/plasma). These data clearly indicate that ceftibuten penetrated well into the MEF to yield clinically effective concentrations.

scholarly journals Disposition Kinetics of Amitraz in Lactating Does

Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 4769
Author(s):  
Sathish Nanjundappa ◽  
Suresh Narayanan Nair ◽  
Darsana Udayan ◽  
Sreelekha Kanapadinchareveetil ◽  
Mathew Jacob ◽  
...  
Keyword(s):  
High Performance ◽  
Area Under The Curve ◽  
Apparent Volume ◽  
Volume Of Distribution ◽  
Health Concern ◽  
Laboratory Animals ◽  
Disposition Kinetics ◽  
Kinetics Of ◽  
Apparent Volume Of Distribution ◽  
Dermal Application

Amitraz, a member of the formamidine pesticide family, commonly used for ectoparasite control, is applied as a dip or low-pressure hand spray to cattle and swine, and the neck collar on dogs. Data on amitraz were generated mainly on laboratory animals, hens, dogs, and baboons. The data on the toxicity and disposition of amitraz in animals and its residues in the milk are inadequate. Therefore, the present study was intended to analyze the disposition kinetics of amitraz and its pattern of elimination in the milk of lactating does after a single dermal application at a concentration of 0.25%. Blood at predetermined time intervals and milk twice daily were collected for eight days post application. The drug concentration was assayed by high-performance liquid chromatography (HPLC). Amitraz was detected in whole blood as early as 0.5 h, which attained a peak concentration at 12 ± 5 h, followed by a steady decline; however, detection persisted until 168 h. Amitraz was present in the blood at its 50% Cmax even after 48 h, and was still detectable after 7 days. The disposition after a single dermal application was best described non-compartmentally. The mean terminal half-life (t1/2), mean residence time (MRT), and area under the curve (AUC0–t) were 111 ± 31 h, 168 ± 39 h, and 539 ± 211 µg/mL/h, respectively. The apparent volume of distribution (Vdarea) was 92 ± 36 mL/g with an observed clearance (Cl) of 0.57 ± 0.33 mL/kg/h. Thus, the drug was well absorbed, widely distributed and slowly eliminated from the animal body. Amitraz achieved milk concentration approximating 0.2 per cent of the total dose after a single exposure and the steady-state elimination of amitraz in milk above the recommended maximum residue limit (MRL) of 0.01 mg/kg can act as a source of public health concern when applied on lactating animals.

scholarly journals Pharmacokinetic Study of Modafinil in Relation to Gender and Ethnicity in Healthy Young Chinese Volunteers

2010 ◽  
Vol 13 (3) ◽  
pp. 443 ◽  
Author(s):  
Tao Guo ◽  
Longshan Zhao ◽  
Dong-Ya Xia
Keyword(s):  
Body Weight ◽  
Oral Dose ◽  
High Performance ◽  
Area Under The Curve ◽  
Total Body Weight ◽  
Apparent Volume ◽  
Pharmacokinetic Parameters ◽  
Maximum Plasma ◽  
Significant Difference ◽  
Total Body

Purpose. The pharmacokinetics of modafinil were investigated in relation to gender and ethnicity in healthy young volunteers from Han, Mongolian, Korean, Uygur and Hui ( n = 10/group) following administration of a single 200 mg oral dose. Methods. Blood samples were collected over 48 h for the determination of plasma levels of modafinil and its acid metabolite by High performance liquid chromatography with an ultraviolet detector. Pharmacokinetic parameters were evaluated using noncompartmental methods. Results. Modafinil was well tolerated and safe at a single oral dose of 200 mg. All participants reported adverse events, none of which was serious or unexpected. The maximum plasma concentration (Cmax) and area under the curve for modafinil concentration versus time, which was extrapolated to infinity (AUC0-∞), were higher in women compared to men (p < 0.01). No gender-based difference was noted in the total body weight-normalized modafinil oral clearance. The total body weight-normalized modafinil apparent volume of distribution and the t1/2 was found to exhibit an ethnicity-based significant difference. Conclusion. The results of the current study suggest that there might be pharmacokinetic differences related to gender and ethnicity in the pharmacokinetics of modafinil.

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.

The Pharmacokinetics of Buserelin after Intramuscular Administration in Pigs and Cows

2021 ◽  
Author(s):  
Zhengrong Gao ◽  
Yu Liu ◽  
Yuxin Yang ◽  
Yuying Cao ◽  
Jicheng Qiu ◽  
...  
Keyword(s):  
Area Under The Curve ◽  
Apparent Volume ◽  
Ultra Performance Liquid Chromatography ◽  
Volume Of Distribution ◽  
Pharmacokinetic Parameters ◽  
Maximum Plasma ◽  
Elimination Half ◽  
Liquid Chromatography Tandem Mass ◽  
Stability Method ◽  
Apparent Volume Of Distribution

Abstract Background: Buserelin is a LHRH agonist used for the treatment of hormone-dependent diseases in males and females. However, the pharmacokinetics of buserelin in pigs and cows are not clearly understood. This study was designed to develop a sensitive method to determine the concentration of buserelin and to investigate the pharmacokinetic parameters after intramuscular (i.m.) administration in pigs and cows. Results: A sensitive and rapid stability method based on ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) was developed. The pharmacokinetic parameters of buserelin after i.m. administration were studies in five pigs and five cows at a single dose of 1 mg per pig and 3 mg per cow. The plasma kinetics were analyzed by WinNonlin 8.1.0 software using a non-compartmental model. The mean concentration area under the curve (AUC0-t) was 25.02 ± 6.93 h·ng/mL for pigs and 5.63 ±1.86 h·ng/mL for cows. The maximum plasma concentration (Cmax) and time to reach the maximum concentration (tmax) were 10.99 ± 2.04 ng/mL and 0.57 ± 0.18 h for pigs and 2.68 ± 0.36 ng/mL and 1.05 ±0.27 h for cows, respectively. The apparent volume of distribution (Vz) in pigs and cows was 80.49 ± 43.88 L and 839.88 ± 174.77 L, respectively. The elimination half-time (t1/2λz), and clearance (CL) were 1.29 ± 0.40 h and 41.15 ± 11.18 L/h for pigs and 1.13 ± 0.3 h and 545.04 ± 166.40 L/h for cows, respectively. No adverse effects were observed in any of the animals. Conclusion: This study extends previous studies describing the pharmacokinetics of buserelin following i.m. administration in pigs and cows. Further studies investigating other factors were needed to establish therapeutic protocol in pigs and cows and to extrapolate these parameters to others economic animals.

scholarly journals Pharmacokinetics of saquinavir, zidovudine, and zalcitabine in combination therapy.

1997 ◽  
Vol 41 (11) ◽  
pp. 2428-2432 ◽  
Author(s):  
G F Vanhove ◽  
H Kastrissios ◽  
J M Gries ◽  
D Verotta ◽  
K Park ◽  
...  
Keyword(s):  
Half Life ◽  
Area Under The Curve ◽  
Chronic Administration ◽  
Volume Of Distribution ◽  
Pharmacokinetic Parameters ◽  
Parameter Estimates ◽  
Pharmacokinetic Studies ◽  
Mean Values ◽  
Aids Clinical Trial Group ◽  
The Mean

We investigated the pharmacokinetics of zidovudine, zalcitabine, and saquinavir in AIDS Clinical Trial Group protocol 229. Patients received either saquinavir, zalcitabine, or a combination of both, together with zidovudine three times a day. Approximately 100 patients were enrolled in each treatment arm, and intensive pharmacokinetic studies were performed on about 25 patients per arm at weeks 1 and 12. We estimated the pharmacokinetic parameters of all three drugs by using parametric and nonparametric methods. The mean values of the pharmacokinetic parameters of zidovudine (clearance [CL]/bioavailability [F], 168 liters/h; volume of distribution [V]/F, 185 liters; half-life, 0.76 h) and zalcitabine (CL/F, 25 liters/h; V/F, 92.2 liters; half-life, 2.7 h) were similar to those reported previously. For saquinavir, the mean pharmacokinetic parameter estimates using parametric methods were as follows: maximum concentration of drug in serum [Cmax], 70.8 ng/ml; time to Cmax, 3.11 h; area under the curve, 809 ng x h/ml; CL/F, 989 liters/h; V/F, 1,503 liters; half-life, 1.38 h. For all three drugs, clearance decreased with age. Weight did not influence the clearance of zidovudine, but the clearance of zalcitabine and saquinavir increased with weight. There were no differences in pharmacokinetic parameters between study weeks and arms, suggesting that there is no change in kinetics with chronic administration and that there are no significant pharmacokinetic interactions among these three drugs.

scholarly journals Studies on effects of lactose on experimental Trypanosoma vivax infection in Zebu cattle. 1. Plasma kinetics of intravenously administered lactose at onset of infection and pathology

2008 ◽  
Vol 75 (2) ◽  
Author(s):  
M. Y. Fatihu ◽  
S. Adamu ◽  
I. A. Umar ◽  
N. D.G. Ibrahim ◽  
L. O. Eduvie ◽  
...  
Keyword(s):  
Muscular Atrophy ◽  
Elimination Rate ◽  
Apparent Volume ◽  
Volume Of Distribution ◽  
Pharmacokinetic Parameters ◽  
Zebu Cattle ◽  
Trypanosoma Vivax ◽  
Histopathological Lesions ◽  
The Mean ◽  
Total Body

Lactose in normal saline was administered intravenously to a group of Zebu cattle infected with Trypanosoma vivax to determine the bloodplasma kinetics at onset of an experimental infection and its ability to protect tissues against damage as part of preliminary studies to determine its suitability for use in the treatment of trypanosomosis. Significant (P <0.01) higher lactose concentrations were observed in the T. vivax-intecled bulls at 30 min and 1h (P< 0.05) post-infectio (p.i.) and by 4 h p.i. the plasma lactose remained above the level prior to infusion, after which it fell slightly below the preinfusion level in the uninfected group. Calculated pharmacokinetic parameters revealed delayed excretion of lactose in the T. vivax-intected group soon after infection. The total body clearance (C/B )was significantly (P < 0.05) reduced. The biological half-life (t1/2), elimination rate constant (kel) and apparent volume of distribution (Vd) were relatively decreased (P > 0.05) as a result of the T. vivax infection. Retention of lactose in the plasma was attributed to decreased plasma clearance l.t is suggested that the presence of trypanosomes in circulation rather than organic lesions could have been responsible for the delay observed in the excretion of lactose.At 12 weeks p.i., when the experiment was terminated, the group infected and given lactose infusion (despiteh igherp arasitaemia) had no gross or histopathological lesions in the brain, spleen, lymphnodes, heart, kidneys, liver and testes. However, the group infected but not infused with lactose were emaciated, had pale mucosae, watery blood, general muscular atrophy, serous atrophy of coronary fat and other adiposet issue, hepatomegalys, plenomegalys, wollen and oedematous lymph nodes, all of which are suggestive of trypanosomosis. Histopathological lesions included arrowing of Bowman's space and hypercellularity of glomerular tufts in the kidneys with the mean glomerula truft nucleairn dices (GTNs) in the group significantly higher (P <0.01)than the mean GTNs of the lactoseinfused and control bulls. Degenerative changes occurred in the myocardium, spleen, testes and epididymides. The tesicular and epididymal lesions are indicative of male reproductive dysfunction.

scholarly journals Evaluation of the pharmacokinetics of the simultaneous quantification of letrozole and palbociclib in rat plasma by a developed and validated HPLC–PDA

2020 ◽  
Vol 32 (3) ◽  
pp. 170-178
Author(s):  
Mona Al-Shehri ◽  
Mohamed Hefnawy ◽  
Hatem Abuelizz ◽  
Adeeba Alzamil
Keyword(s):  
High Performance ◽  
Intraperitoneal Administration ◽  
Rat Plasma ◽  
Reversed Phase ◽  
Photodiode Array Detection ◽  
Chromatography Method ◽  
Mean Values ◽  
The Us ◽  
The Mean ◽  
Liquid Chromatography Method

The US Food and Drug Administration (FDA) has affirmed the use of letrozole (LTZ) combined with palbociclib (PLB) to treat breast malignant tumor growth in postmenopausal women. A straightforward and extremely sensitive reversed-phase high-performance liquid chromatography method with photodiode array detection (RP-HPLC–PDA) was created and validated for the simultaneous determination of LTZ and PLB in rat plasma. The parameters used to give the best separation were a C18 column (150 mm × 4.6 mm, 3.5 μm) as the stationary phase with an isocratic mobile phase composed of methanol–30 mM ammonium acetate at a ratio of 60:40 (v/v), pH = 5.5, a flow rate of 0.8 mL/min, and detection wavelengths of 240 and 220 nm for LTZ and PLB, respectively. The developed method was assessed by the FDA rules over a range of 10–600 ng/mL for LTZ and PLB. The mean of %recovery of LTZ and PLB extracted from rat plasma by acetonitrile-based deproteinization was 91.06 ± 2.73 and 90.30 ± 1.95%, respectively, and the limits of detection were 5 ng/mL for LTZ and 7 ng/mL for PLB in rat plasma. The mean values of Tmax and Cmax were 6 ± 0.00 h and 266.96 ± 21.23 ng/mL for LTZ and 4 ± 0.00 h and 508.75 ± 61.56 ng/mL for PBL, respectively, after intraperitoneal administration of both drugs to rats. The developed HPLC–PDA method was demonstrated to be robust and was effectively applied to study the pharmacokinetics of LTZ and PLB in rat plasma.

Pharmacokinetics of undiluted or diluted high-dose etoposide with or without busulfan administered to patients with hematologic malignancies.

1994 ◽  
Vol 12 (7) ◽  
pp. 1468-1474 ◽  
Author(s):  
K Mross ◽  
P Bewermeier ◽  
W Krüger ◽  
M Stockschläder ◽  
A Zander ◽  
...  
Keyword(s):  
High Performance ◽  
Drug Exposure ◽  
Area Under The Curve ◽  
Volume Of Distribution ◽  
Pharmacokinetic Parameters ◽  
High Dose ◽  
Pharmacokinetic Data ◽  
Blood Samples ◽  
Systemic Drug Exposure ◽  
Systemic Drug

PURPOSE We used two different methods to administer high-dose etoposide (VP-16) during a myeloablative conditioning chemotherapy regimen before bone marrow transplantation (BMT). VP-16 was administered either diluted (0.5 mg/mL) or undiluted (20 mg/mL), with or without busulfan. PATIENTS AND METHODS Blood samples were drawn from 17 patients during the infusion (6 hours) and thereafter daily until 2 days after BMT. VP-16 concentrations were measured in all plasma samples by high-performance liquid chromatography (HPLC) and electrochemical detection, and the results were analyzed with a pharmacokinetic data analysis system. RESULTS All calculated pharmacokinetic parameters in the two patient groups (VP-16 administered diluted or undiluted) were similar. There were no statistically significant differences in half-lives, mean residence time (MRT), volume of distribution, total clearance, or area under the curve (AUC). VP-16 was found in blood samples from eight of 17 patients at the time of BMT. Significant differences in systemic drug exposure and systemic clearance were found when patients were grouped according to treatment with busulfan or with total-body irradiation (TBI). CONCLUSION The two administration modes for VP-16, either diluted or undiluted, are bioequivalent in pharmacokinetic terms. The terminal half-lives were longer than expected and resulted in significant VP-16 plasma levels at the time of BMT. The biologic significance remains unclear. Busulfan and/or concomitant medication with phenytoin influence plasma clearance (clp) and systemic drug exposure significantly.

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