Validation of Sparse Sampling Strategies to Estimate Cyclosporine A Area Under the Concentration-Time Curve Using Either a Specific Radioimmunoassay or High-Performance Liquid Chromography Method

2010 ◽  
Vol 32 (5) ◽  
pp. 586-593 ◽  
Author(s):  
Blanka Koristkova ◽  
Milan Grundmann ◽  
Hana Brozmanova ◽  
Ilona Perinova ◽  
Kristian Safarcik
Keyword(s):  
Cyclosporine A ◽  
High Performance ◽  
Sparse Sampling ◽  
Sampling Strategies ◽  
Time Curve ◽  
Concentration Time ◽  
Specific Radioimmunoassay

scholarly journals Administration of aminoglycosides to hemodialysis patients immediately before dialysis: a new dosing modality.

1997 ◽  
Vol 41 (12) ◽  
pp. 2597-2601 ◽  
Author(s):  
H Matsuo ◽  
J Hayashi ◽  
K Ono ◽  
K Andoh ◽  
Y Andoh ◽  
...  
Keyword(s):  
High Performance ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Cellulose Triacetate ◽  
The Body ◽  
High Rate ◽  
Complete Disappearance ◽  
Time Curve ◽  
Once Daily ◽  
Ethylene Vinyl Alcohol ◽  
Concentration Time

We describe a new modality for administering aminoglycosides to hemodialysis (HD) patients, namely, a modification of the once-daily regimen which consists of administering the aminoglycosides over 60 min by drip infusion just before each HD session, with a preplanned peak concentration being reached at the beginning of the session and then with a rapidly decreasing concentration being achieved by the start of HD. The area under the concentration-time curve (AUC), i.e., the accumulation of the drug in the body, is thus minimized by this modality. Arbekacin (ABK) was given at a dose of 2 mg/kg of body weight to 10 HD patients infected with methicillin-resistant Staphylococcus aureus (MRSA) for 2 weeks (six sessions in total), resulting in the complete disappearance of MRSA in 5 patients. A high rate of elimination of ABK was attained for each patient while the patient was on HD (range, 0.20 to 0.42 h-1; mean 0.28 +/- 0.08 h-1) by using high-performance dialyzers provided with membranes made of either polymethylmethacrylate, cellulose triacetate (CTA), or ethylene vinyl alcohol. The best results were obtained with the CTA membrane, as revealed by the overall mass transfer coefficient (Ko). The AUC in the simulation model for the variation in the serum ABK concentration in this modality was calculated to be 40% of that of the conventional post-HD dosing modality, suggesting that a much higher dose could be administered to HD patients who receive HD thrice weekly (4 h per session), giving, e.g., 4 mg/kg initially and before the HD sessions, when there is an interval of 68 h from HD session to HD session, and giving 2 mg/kg before the other sessions.

scholarly journals Lack of Effect of Zafirlukast on the Pharmacokinetics of Azithromycin, Clarithromycin, and 14-Hydroxyclarithromycin in Healthy Volunteers

1999 ◽  
Vol 43 (5) ◽  
pp. 1152-1155 ◽  
Author(s):  
Kevin W. Garey ◽  
Charles A. Peloquin ◽  
Paul G. Godo ◽  
Anne N. Nafziger ◽  
Guy W. Amsden
Keyword(s):  
Steady State ◽  
Healthy Subjects ◽  
High Performance ◽  
Pharmacokinetic Parameters ◽  
Steady State Concentration ◽  
Open Label ◽  
Time Curve ◽  
Data Analyses ◽  
Concentration Time ◽  
State Concentration

ABSTRACT This randomized, open-label, crossover study was conducted to investigate whether the coadministration of zafirlukast would affect the pharmacokinetics of azithromycin, clarithromycin, or 14-hydroxyclarithromycin (14-OHC). Twelve healthy subjects (six males and six females) received single 500-mg doses of azithromycin and clarithromycin with and without zafirlukast given to a steady-state concentration. Blood was collected prior to all macrolide doses and for 3 and 10 days after each clarithromycin and azithromycin dose, respectively. Serum was assayed for azithromycin, clarithromycin, and 14-OHC concentrations by validated high-performance liquid chromatography assay systems. Data analyses were done by noncompartmental and nonparametric methods. Analysis of the patients indicated that the addition of steady-state concentrations of zafirlukast did not significantly alter the pharmacokinetic parameters of or overall exposure (based on the area under the concentration-time curve) to azithromycin, clarithromycin, and 14-OHC. While zafirlukast is a known inhibitor of CYP3A4, it does not appear to exert a clinically or statistically significant pharmacokinetic effect on azithromycin, clarithromycin, or 14-OHC.

Limited Sampling Strategies to Estimate the Area under the Concentration-time Curve

2012 ◽  
Vol 51 (05) ◽  
pp. 383-394 ◽  
Author(s):  
M. Fukumoto ◽  
L. Bax ◽  
A. Kohno ◽  
Y. Morishita ◽  
H. Tsuruta
Keyword(s):  
Rate Constant ◽  
Elimination Rate ◽  
Estimation Method ◽  
Pharmacokinetic Parameters ◽  
Good Precision ◽  
Sampling Strategies ◽  
Time Curve ◽  
New Methods ◽  
Limited Sampling ◽  
Concentration Time

SummaryBackground: Over 100 limited sampling strategies (LSSs) have been proposed to reduce the number of blood samples necessary to estimate the area under the concentration-time curve (AUC). The conditions under which these strategies succeed or fail remain to be clarified.Objectives: We investigated the accuracy of existing LSSs both theoretically and numerically by Monte Carlo simulation. We also proposed two new methods for more accurate AUC estimations.Methods: We evaluated the following existing methods theoretically: i) nonlinear curve fitting algorithm (NLF), ii) the trapezium rule with exponential curve approximation (TZE), and iii) multiple linear regression (MLR). Taking busulfan (BU) as a test drug, we generated a set of theoretical concentration-time curves based on the identified distribution of pharmacokinetic parameters of BU and re-evaluated the existing LSSs using these virtual validation profiles. Based on the evaluation results, we improved the TZE so that unrealistic parameter values were not used. We also proposed a new estimation method in which the most likely curve was selected from a set of pre-generated theoretical concentration-time curves.Results: Our evaluation, based on clinical profiles and a virtual validation set, revealed: i) NLF sometimes overestimated the absorption rate constant Ka, ii) TZE overestimated AUC over 280% when Ka is small, and iii) MLR underestimated AUC over 30% when the elimination rate constant Ke is small. These results were consistent with our mathematical evaluations for these methods. In contrast, our two new methods had little bias and good precision.Conclusions: Our investigation revealed that existing LSSs induce different but specific biases in the estimation of AUC. Our two new LSSs, a modified TZE and one using model concentration-time curves, provided accurate and precise estimations of AUC.

NEORAL MONITORING BY SIMPLIFIED SPARSE SAMPLING AREA UNDER THE CONCENTRATION-TIME CURVE

1999 ◽  
Vol 68 (1) ◽  
pp. 55-62 ◽  
Author(s):  
Kamran Mahalati ◽  
Philip Belitsky ◽  
Ingrid Sketris ◽  
Kenneth West ◽  
Romauld Panek
Keyword(s):  
Sparse Sampling ◽  
Sampling Area ◽  
Time Curve ◽  
Concentration Time

scholarly journals Rifampin Reduces Concentrations of Trimethoprim and Sulfamethoxazole in Serum in Human Immunodeficiency Virus-Infected Patients

2001 ◽  
Vol 45 (11) ◽  
pp. 3238-3241 ◽  
Author(s):  
Esteban Ribera ◽  
Leonor Pou ◽  
Antoni Fernandez-Sola ◽  
Francisco Campos ◽  
Rosa M. Lopez ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
High Performance Liquid Chromatography ◽  
High Performance ◽  
Parent Drug ◽  
Time Curve ◽  
Once Daily ◽  
Concentration Time ◽  
Antituberculosis Treatment ◽  
Immunodeficiency Virus ◽  
Before And After

ABSTRACT To determine whether rifampin reduces concentrations of trimethoprim (TMP) and sulfamethoxazole (SMX) in serum of human immunodeficiency virus (HIV)-infected persons, levels of these agents were determined by high-performance liquid chromatography before and after more than 12 days of standard antituberculosis treatment for 10 patients who had been taking one double-strength tablet of co-trimoxazole once daily for more than 1 month. Statistically significant, 47 and 23% decreases in TMP and SMX mean areas under the concentration-time curve from 0 to 24 h (AUC0–24), respectively, were observed after administration of rifampin.N-Acetyl-SMX profiles without and with rifampin were similar. The steady-state AUC0–24 metabolite/parent drug ratio increased by 32% with rifampin administration. Our study shows that rifampin reduces profiles of TMP and SMX in serum of HIV-infected patients.

scholarly journals Pharmacokinetics of sparfloxacin and interaction with cisapride and sucralfate.

1997 ◽  
Vol 41 (8) ◽  
pp. 1668-1672 ◽  
Author(s):  
J A Zix ◽  
H F Geerdes-Fenge ◽  
M Rau ◽  
J Vöckler ◽  
K Borner ◽  
...  
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Peak Concentration ◽  
High Performance ◽  
Random Order ◽  
Pharmacokinetic Parameters ◽  
Qtc Interval ◽  
Urinary Recovery ◽  
Time Curve ◽  
Concentration Time

In an open, randomized, triple crossover study, the effects of cisapride and sucralfate on the pharmacokinetics of sparfloxacin were assessed. Fifteen healthy volunteers received 400 mg of sparfloxacin as a single oral dose on day 0. In a random order, concomitant doses of 10 mg of cisapride three times daily from day -2 to day 2 and 1 g of sucralfate four times daily from day -2 to day 0 were administered. Sparfloxacin concentrations were measured by bioassay and high-performance liquid chromatography. Pharmacokinetic parameters for sparfloxacin alone were as follows (mean +/- standard deviation): maximum concentration of drug in serum (C(max)), 1.27 +/- 0.39 microg/ml; time to C(max) (T(max)), 4.1 +/- 1.9 h; area under the concentration-time curve (AUC), 35.0 +/- 9.7 microg x h/ml; mean residence time, 28.5 +/- 5.7 h; half-life (t1/2), 20 +/- 4 h; urinary recovery (UR x f), 11.0% +/- 2.7%; and metabolite-sparfloxacin ratio in urine, 2.6. For the cisapride group there was a significant decrease in the sparfloxacin T(max) (1.9 +/- 2.1 h) and a significant increase in C(max) (1.74 +/- 0.73 microg/ml). The QTc interval for patients receiving sparfloxacin and cisapride was prolonged by 7.7% compared to the QTc interval during medication-free periods. Significant differences in the values for the group receiving sucralfate compared to the values for the group receiving sparfloxacin alone were found: C(max), 0.77 +/- 0.31 microg/ml; AUC, 18.6 +/- 5.8 microg x h/ml; t1/2, 26 +/- 10 h; and UR x f, 5.8 +/- 1.8%. Concomitant adminstration of cisapride accelerates the absorption and increases the peak concentration of sparfloxacin without having a significant effect on the extent of bioavailability. Coadministration of sucralfate leads to a 44% decrease in the bioavailability of sparfloxacin.

scholarly journals Comparing Pharmacokinetics of Amoxicillin Given Twice or Three Times per Day to Children Older than 3 Months with Pneumonia

2003 ◽  
Vol 47 (3) ◽  
pp. 997-1001 ◽  
Author(s):  
Walter Fonseca ◽  
Kalle Hoppu ◽  
Luís C. Rey ◽  
João Amaral ◽  
Shamim Qazi
Keyword(s):  
High Performance ◽  
Dose Interval ◽  
World Health ◽  
Time Curve ◽  
Oral Amoxicillin ◽  
Concentration Time ◽  
Feasible Alternative ◽  
The Mean ◽  
Health Organization ◽  
Body Weight Dose

ABSTRACT For children with ambulatory pneumonia, the World Health Organization (WHO) recommends oral amoxicillin (15 mg/kg of body weight/dose) thrice daily (t.i.d.) or oral cotrimoxazole (4 mg of trimethoprim/kg/dose) twice daily (b.i.d.). The more frequent amoxicillin dosing may lead to compliance problems. To compare the pharmacokinetics and levels of amoxicillin in plasma in the current WHO acute respiratory infection recommendations with the 25-mg/kg/dose b.i.d. regimen, we performed a two-group parallel study of 66 children ages 3 to 59 months with pneumonia. Amoxicillin was given orally at 25 mg/kg/dose b.i.d. or 15 mg/kg/dose t.i.d. Amoxicillin concentrations were determined by high-performance liquid chromatography after the first dose on days 1 and 3. After the first dose on day 1, the mean area under the concentration-time curve (AUC) for amoxicillin after the 25-mg/kg dose was 54.7 versus 24.9 μg · h/ml after the 15-mg/kg dose. After the first dose on day 3, the mean AUC was 44.1 versus 28.5 μg · h/ml. All but two children had plasma amoxicillin concentrations above 0.5 μg/ml for >50% of the dose interval on both days. Six children on day 1 and five children on day 3 had concentrations above 1.0 μg/ml for <50% of the dose interval. On day 1, 16 of 27 children in the b.i.d. group and 11 of 26 children in the t.i.d. group had concentrations that were above 2.0 μg/ml for <50% of the dose interval, and on day 3, 18 of 31 children in the b.i.d. group and 8 of 31 children in the t.i.d. group had concentrations that were above 2.0 μg/ml for <50% of the dose interval. Amoxicillin b.i.d. is a feasible alternative for t.i.d. dosing. To lengthen the time above the MIC at higher concentration levels, a 30- to 40-mg/kg/dose b.i.d. should be considered instead of the 25 mg/kg/dose used in this study.

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