scholarly journals Low Penetration of Oseltamivir and Its Carboxylate into Cerebrospinal Fluid in Healthy Japanese and Caucasian Volunteers

2008 ◽  
Vol 52 (10) ◽  
pp. 3687-3693 ◽  
Author(s):  
S. S. Jhee ◽  
M. Yen ◽  
L. Ereshefsky ◽  
M. Leibowitz ◽  
M. Schulte ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Influenza A ◽  
Abnormal Behavior ◽  
Oseltamivir Carboxylate ◽  
Open Label ◽  
Time Curve ◽  
Open Label Study ◽  
The Central Nervous System ◽  
Cns Penetration ◽  
Adult Volunteers

ABSTRACT Oseltamivir is a potent, well-tolerated antiviral for the treatment and prophylaxis of influenza. Although no relationship with treatment could be demonstrated, recent reports of abnormal behavior in young individuals with influenza who were receiving oseltamivir have generated renewed interest in the central nervous system (CNS) tolerability of oseltamivir. This single-center, open-label study explored the pharmacokinetics of oseltamivir and oseltamivir carboxylate (OC) in the plasma and cerebrospinal fluid (CSF) of healthy adult volunteers over a 24-hour interval to determine the CNS penetration of both these compounds. Four Japanese and four Caucasian males were enrolled in the study. Oseltamivir and OC concentrations in CSF were low (mean of observed maximum concentrations [C max], 2.4 ng/ml [oseltamivir] and 19.0 ng/ml [OC]) versus those in plasma (mean C max, 115 ng/ml [oseltamivir] and 544 ng/ml [OC]), with corresponding C max CSF/plasma ratios of 2.1% (oseltamivir) and 3.5% (OC). Overall exposure to oseltamivir and OC in CSF was also comparatively low versus that in plasma (mean area under the concentration-time curve CSF/plasma ratio, 2.4% [oseltamivir] and 2.9% [OC]). No gross differences in the pharmacokinetics of oseltamivir or OC were observed between the Japanese and Caucasian subjects. Oseltamivir was well tolerated. This demonstrates that the CNS penetration of oseltamivir and OC is low in Japanese and Caucasian adults. Emerging data support the idea that oseltamivir and OC have limited potential to induce or exacerbate CNS adverse events in individuals with influenza. A disease- rather than drug-related effect appears likely.

scholarly journals Fosamprenavir plus Ritonavir Increases Plasma Ketoconazole and Ritonavir Exposure, while Amprenavir Exposure Remains Unchanged

2007 ◽  
Vol 51 (8) ◽  
pp. 2982-2984 ◽  
Author(s):  
Mary B. Wire ◽  
Charles H. Ballow ◽  
Julie Borland ◽  
Mark J. Shelton ◽  
Yu Lou ◽  
...  
Keyword(s):  
Steady State ◽  
Healthy Subjects ◽  
Open Label ◽  
Time Curve ◽  
Once Daily ◽  
Open Label Study ◽  
Label Study ◽  
Concentration Time

ABSTRACT Plasma ketoconazole (KETO), amprenavir (APV), and ritonavir (RTV) pharmacokinetics were evaluated in 15 healthy subjects after being treated with KETO at 200 mg once daily (QD), fosamprenavir (FPV)/RTV at 700/100 mg twice daily (BID), and then KETO at 200 mg QD plus FPV/RTV at 700/100 mg BID in this open-label study. The KETO area under the concentration-time curve at steady state was increased 2.69-fold with FPV/RTV. APV exposure was unchanged, and RTV exposure was slightly increased.

scholarly journals Open-Label Crossover Study of Primaquine and Dihydroartemisinin-Piperaquine Pharmacokinetics in Healthy Adult Thai Subjects

2014 ◽  
Vol 58 (12) ◽  
pp. 7340-7346 ◽  
Author(s):  
Borimas Hanboonkunupakarn ◽  
Elizabeth A. Ashley ◽  
Podjanee Jittamala ◽  
Joel Tarning ◽  
Sasithon Pukrittayakamee ◽  
...  
Keyword(s):  
Crossover Study ◽  
Hospital Admissions ◽  
Geometric Mean ◽  
Radical Cure ◽  
Open Label ◽  
Time Curve ◽  
Content Type ◽  
Concentration Time ◽  
Pharmacokinetic Assessment ◽  
Adult Volunteers

ABSTRACTDihydroartemisinin-piperaquine is an artemisinin-based combination treatment (ACT) recommended by the WHO for uncomplicatedPlasmodium falciparummalaria, and it is being used increasingly for resistant vivax malaria where combination with primaquine is required for radical cure. The WHO recently reinforced its recommendations to add a single dose of primaquine to ACTs to reduceP. falciparumtransmission in low-transmission settings. The pharmacokinetics of primaquine and dihydroartemisinin-piperaquine were evaluated in 16 healthy Thai adult volunteers in a randomized crossover study. Volunteers were randomized to two groups of three sequential hospital admissions to receive 30 mg (base) primaquine, 3 tablets of dihydroartemisinin-piperaquine (120/960 mg), and the drugs together at the same doses. Blood sampling was performed over 3 days following primaquine and 36 days following dihydroartemisinin-piperaquine dosing. Pharmacokinetic assessment was done with a noncompartmental approach. The drugs were well tolerated. There were no statistically significant differences in dihydroartemisinin and piperaquine pharmacokinetics with or without primaquine. Dihydroartemisinin-piperaquine coadministration significantly increased plasma primaquine levels; geometric mean ratios (90% confidence interval [CI]) of primaquine combined versus primaquine alone for maximum concentration (Cmax), area under the concentration-time curve from 0 h to the end of the study (AUC0–last), and area under the concentration-time curve from 0 h to infinity (AUC0–∞) were 148% (117 to 187%), 129% (103 to 163%), and 128% (102 to 161%), respectively. This interaction is similar to that described recently with chloroquine and may result in an enhanced radical curative effect. (This study has been registered at ClinicalTrials.gov under registration no. NCT01525511.)

scholarly journals Switching to Tenofovir Alafenamide in Elvitegravir-Based Regimens: Pharmacokinetics and Antiviral Activity in Cerebrospinal Fluid

2019 ◽  
Vol 71 (4) ◽  
pp. 982-988 ◽  
Author(s):  
Qing Ma ◽  
Andrew J Ocque ◽  
Gene D Morse ◽  
Chelsea Sanders ◽  
Alina Burgi ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Antiviral Activity ◽  
Virologic Failure ◽  
Plasma Concentrations ◽  
Open Label ◽  
Assay Sensitivity ◽  
Once Daily ◽  
Hiv Rna ◽  
The Central Nervous System ◽  
Tenofovir Alafenamide

Abstract Background Tenofovir alafenamide fumarate (TAF) co-formulated with elvitegravir (EVG; E), cobicistat (C), and emtricitabine (F), a recommended antiretroviral regimen, was evaluated for distribution and antiviral activity in cerebrospinal fluid (CSF) as well as neurocognitive (NC) performance change in participants switching from E/C/F/tenofovir disoproxil fumarate (TDF) to E/C/F/TAF. Methods This was a 24-week, single-arm, open-label study in treatment-experienced adults living with human immunodeficiency virus (HIV). Nine participants switched from E/C/F/TDF (150/150/200/300 mg once daily) to E/C/F/TAF (150/150/200/10 mg once daily) at week 12. CSF and total plasma concentrations of EVG, TDF, TAF, tenofovir (TFV), and HIV RNA levels were measured at baseline and week 24. NC performance was estimated by the Montreal Cognitive Assessment. Results EVG concentrations in CSF and the CSF:plasma ratio remained stable (P = .203) over time. Following the switch, TFV concentrations in CSF and plasma declined (P = .004), although the TFV CSF:plasma ratio increased (P = .004). At week 24, median TAF plasma concentration was 11.05 ng/mL (range, 2.84–147.1 ng/mL) 2 hours postdose but was below assay sensitivity 6 hours after dosing. TAF was below assay sensitivity in all CSF specimens. HIV RNA was ≤40 copies/mL in all CSF and plasma specimens. Three participants (33%) had NC impairment at baseline and 2 (22%) remained impaired at week 24. Conclusions Switch to E/C/F/TAF was associated with reductions in TFV concentrations in CSF but stable EVG concentrations that exceeded the 50% inhibitory concentration for wild-type HIV, suggesting that EVG achieves therapeutic concentrations in the central nervous system. No virologic failure or significant NC changes were detected following the switch. Clinical Trials Registration NCT02251236.

scholarly journals Oseltamivir and Oseltamivir Carboxylate Pharmacokinetics in Obese Adults: Dose Modification for Weight Is Not Necessary

2011 ◽  
Vol 55 (12) ◽  
pp. 5640-5645 ◽  
Author(s):  
Manjunath P. Pai ◽  
Thomas P. Lodise
Keyword(s):  
Active Metabolite ◽  
Influenza A ◽  
Systemic Exposure ◽  
Lean Body Weight ◽  
Population Pharmacokinetic ◽  
Class Iii ◽  
Oseltamivir Carboxylate ◽  
Obese Adults ◽  
Time Curve ◽  
Apparent Clearance

ABSTRACTObesity is an independent risk factor for mortality in patients infected with pandemic influenza A virus (H1N1). Given the poor outcomes observed among adult obese patients with H1N1, the dosing of antiviral agents in this population has been questioned, and use of twice the standard oseltamivir dose has been suggested. However, studies evaluating the disposition of oseltamivir and oseltamivir carboxylate (the active metabolite) in the obese population are scant. We evaluated the single-dose and steady-state pharmacokinetics of oseltamivir (75 mg by mouth twice daily) in a cohort of 21 healthy adult volunteers with class III obesity (body mass index [BMI], ≥40 kg/m2). The median (minimum, maximum) age, weight, and BMI were 36 (19, 50) years, 122 (106, 159) kg, and 43.7 (40.0, 54.4) kg/m2, respectively. The population pharmacokinetic exposure profiles of oseltamivir carboxylate (the active metabolite) were comparable between class III obese subjects and nonobese adults (healthy and infected). Similar to previous pharmacokinetic analyses in nonobese subjects, the mean (percent covariance [CV]) area under the concentration-time curve for the dosing interval (AUC0–τ) was 2,621 ng·h/ml (17) for oseltamivir carboxylate. Body size was significantly (P< 0.05) associated with oseltamivir and oseltamivir carboxylate apparent clearance, but the correlation coefficient was poor (R2≤ 0.3). Creatinine clearance estimated by the Cockcroft-Gault method and lean body weight were also significantly (P< 0.05) but poorly (R2= 0.17) correlated with oseltamivir carboxylate apparent clearance. Since the systemic exposure of oseltamivir carboxylate is not reduced in class III obese adults with standard doses, a dose increment of oseltamivir is likely to be unnecessary.

scholarly journals Nonclinical Pharmacokinetics of Oseltamivir and Oseltamivir Carboxylate in the Central Nervous System

2009 ◽  
Vol 53 (11) ◽  
pp. 4753-4761 ◽  
Author(s):  
Gerhard Hoffmann ◽  
Christoph Funk ◽  
Stephen Fowler ◽  
Michael B. Otteneder ◽  
Alexander Breidenbach ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Active Transport ◽  
Active Metabolite ◽  
Influenza A ◽  
Transport Processes ◽  
Oseltamivir Carboxylate ◽  
The Central Nervous System ◽  
Oral Doses

ABSTRACT Oseltamivir, a potent and selective inhibitor of influenza A and B virus neuraminidases, is a prodrug that is systemically converted into the active metabolite oseltamivir carboxylate. In light of reported neuropsychiatric events in influenza patients, including some taking oseltamivir, and as part of a full assessment to determine whether oseltamivir could contribute to, or exacerbate, such events, we undertook a series of nonclinical studies. In particular, we investigated (i) the distribution of oseltamivir and oseltamivir carboxylate in the central nervous system of rats after single intravenous doses of oseltamivir and oseltamivir carboxylate and oral doses of oseltamivir, (ii) the active transport of oseltamivir and oseltamivir carboxylate in vitro by transporters located in the blood-brain barrier, and (iii) the extent of local conversion of oseltamivir to oseltamivir carboxylate in brain fractions. In all experiments, results showed that the extent of partitioning of oseltamivir and especially oseltamivir carboxylate to the central nervous system was low. Brain-to-plasma exposure ratios were approximately 0.2 for oseltamivir and 0.01 for oseltamivir carboxylate. Apart from oseltamivir being a good substrate for the P-glycoprotein transporter, no other active transport processes were observed. The conversion of the prodrug to the active metabolite was slow and limited in human and rat brain S9 fractions. Overall, these studies indicate that the potential for oseltamivir and oseltamivir carboxylate to reach the central nervous system in high quantities is low and, together with other analyses and studies, that their involvement in neuropsychiatric events in influenza patients is unlikely.

scholarly journals The pharmacokinetics of pamiparib in the presence of a strong CYP3A inhibitor (itraconazole) and strong CYP3A inducer (rifampin) in patients with solid tumors: an open-label, parallel-group phase 1 study

2021 ◽  
Author(s):  
Song Mu ◽  
Chester Lin ◽  
Anna Skrzypczyk-Ostaszewicz ◽  
Iurie Bulat ◽  
Marina Maglakelidze ◽  
...  
Keyword(s):  
Solid Tumors ◽  
Phase 1 ◽  
Open Label ◽  
Phase 1 Study ◽  
Time Curve ◽  
Clinical Safety ◽  
Once Daily ◽  
Cns Penetration ◽  
Dose Modifications ◽  
Cyp3a Inhibitor

Abstract Purpose Pamiparib is an investigational, selective, oral poly(ADP-ribose) polymerase 1/2 (PARP1/2) inhibitor that has demonstrated PARP–DNA complex trapping and CNS penetration in preclinical models, as well as preliminary anti-tumor activity in early-phase clinical studies. We investigated whether the single-dose pharmacokinetic (PK) profile of pamiparib is altered by coadministration of a strong CYP3A inducer (rifampin) or a strong CYP3A inhibitor (itraconazole) in patients with solid tumors. Methods In this open-label, phase 1 study, adults with advanced solid tumors received either oral pamiparib 60 mg (days 1 and 10) and once-daily oral rifampin 600 mg (days 3–11) or oral pamiparib 20 mg (days 1 and 7) and once-daily oral itraconazole 200 mg (days 3–8). Primary endpoints included pamiparib maximum observed concentration (Cmax), and area under the plasma concentration–time curve from zero to last quantifiable concentration (AUC0–tlast) and infinity (AUC0–inf). Secondary endpoints included safety and tolerability. Results Rifampin coadministration did not affect pamiparib Cmax (geometric least-squares [GLS] mean ratio 0.94; 90% confidence interval 0.83–1.06), but reduced its AUC0–tlast (0.62 [0.54–0.70]) and AUC0–inf (0.57 [0.48–0.69]). Itraconazole coadministration did not affect pamiparib Cmax (1.05 [0.95–1.15]), AUC0–tlast (0.99 [0.91–1.09]), or AUC0–inf (0.99 [0.90–1.09]). There were no serious treatment-related adverse events. Conclusions Pamiparib plasma exposure was reduced 38–43% with rifampin coadministration but was unaffected by itraconazole coadministration. Pamiparib dose modifications are not considered necessary when coadministered with CYP3A inhibitors. Clinical safety and efficacy data will be used with these results to recommend dose modifications when pamiparib is coadministered with CYP3A inducers.

scholarly journals Effects of Ritonavir on Indinavir Pharmacokinetics in Cerebrospinal Fluid and Plasma

2003 ◽  
Vol 47 (7) ◽  
pp. 2131-2137 ◽  
Author(s):  
David W. Haas ◽  
Benjamin Johnson ◽  
Janet Nicotera ◽  
Vicki L. Bailey ◽  
Victoria L. Harris ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Low Dose ◽  
Drug Penetration ◽  
Time Curve ◽  
Concentration Time ◽  
Immunodeficiency Virus ◽  
The Central Nervous System ◽  
Intensive Sampling ◽  
Hiv 1

ABSTRACT Therapeutic control of human immunodeficiency virus type 1 (HIV-1) in peripheral compartments does not assure control in the central nervous system. Inadequate drug penetration may provide a sanctuary from which resistant virus can emerge or allow development of psychomotor abnormalities. To characterize the effect of ritonavir on indinavir disposition into cerebrospinal fluid, seven HIV-infected adults underwent intensive sampling at steady-state while receiving twice-daily indinavir (800 mg) and ritonavir (100 mg). Serial cerebrospinal fluid and plasma samples were obtained at 10 time points from each subject. Free indinavir accounted for 98.6% of drug in cerebrospinal fluid and 55.9% in plasma. Mean cerebrospinal fluid C max, C min, and area under the concentration-time curve from 0 to 12 h (AUC0-12) values for free indinavir were 735 nM, 280 nM, and 6,502 nM h−1, respectively, and the free levels exceeded 100 nM in every sample. The cerebrospinal fluid/plasma AUC0-12 ratio for free indinavir was 17.5% ± 6.4%. This ratio was remarkably similar to results obtained in a previous study in which subjects received indinavir without ritonavir, indicating that ritonavir did not have a substantial direct effect on the barrier to indinavir penetration into cerebrospinal fluid. Low-dose ritonavir increases cerebrospinal fluid indinavir concentrations substantially more than 800 mg of indinavir given thrice daily without concomitant ritonavir, despite a lower total daily indinavir dose.

Oral Bioavailability of Nizatidine and Ranitidine Concurrently Administered with Antacid

1989 ◽  
Vol 17 (1) ◽  
pp. 62-67 ◽  
Author(s):  
J. P. Desager ◽  
C. Harvengt
Keyword(s):  
High Performance ◽  
Drug Application ◽  
Open Label ◽  
Time Curve ◽  
Open Label Study ◽  
Concentration Time ◽  
Neutralizing Capacity ◽  
Significant Difference ◽  
Student’S T ◽  
Student’S T Test

This four-way crossover open-label study on eight healthy subjects was designed to investigate the effect on bioavailability of orally administered nizatidine given concurrently with an antacid (magnesium hydroxide–aluminium hydroxide mixture). Ranitidine was used as a comparison. Subjects were hospitalized overnight for each drug application which was given as a single dose [nizatidine or ranitidine (300 mg) or antacid (20 ml) of a neutralizing capacity of 50 mmol hydrochloric acid]. Plasma nizatidine or ranitidine concentrations were measured by high performance liquid chromatography. No statistically significant difference occurred in the kinetic profile of nizatidine after antacid administration although it took longer to reach maximum concentration in plasma. The area under the concentration–time curve was also reduced (by ≤10%) and there was a longer lag between administration and absorption. Bioequivalence (Westlake test) for ranitidine in the presence or absence of antacid was confirmed (difference ≤12%). For nizatidine, with or without antacid, the value of the Westlake test was just above the limit for bioequivalence (21.4%), whereas the Student's t-test for related means (one-tailed distribution) gave P = 0.045. There was no clinically relevant nizatidine–antacid interaction at the doses used in this study.

scholarly journals Phase I, Open-Label, Safety and Pharmacokinetic Study To Assess Bronchopulmonary Disposition of Intravenous Eravacycline in Healthy Men and Women

2014 ◽  
Vol 58 (4) ◽  
pp. 2113-2118 ◽  
Author(s):  
Kevin P. Connors ◽  
Seth T. Housman ◽  
J. Samuel Pope ◽  
John Russomanno ◽  
Edward Salerno ◽  
...  
Keyword(s):  
Respiratory Infections ◽  
Correction Method ◽  
Pharmacokinetic Parameters ◽  
Open Label ◽  
Time Curve ◽  
Epithelial Lining Fluid ◽  
Drug Concentrations ◽  
Penetration Ratio ◽  
Liquid Chromatography Tandem Mass ◽  
Adult Volunteers

ABSTRACTThis study evaluated the pulmonary disposition of eravacycline in 20 healthy adult volunteers receiving 1.0 mg of eravacycline/kg intravenously every 12 h for a total of seven doses over 4 days. Plasma samples were collected at 0, 1, 2, 4, 6, and 12 h on day 4, with each subject randomized to undergo a single bronchoalveolar lavage (BAL) at 2, 4, 6, or 12 h. Drug concentrations in plasma, BAL fluid, and alveolar macrophages (AM) were determined by liquid chromatography-tandem mass spectrometry, and the urea correction method was used to calculate epithelial lining fluid (ELF) concentrations. Pharmacokinetic parameters were estimated by noncompartmental methods. Penetration for ELF and AM was calculated by using a ratio of the area under the concentration time curve (AUC0–12) for each respective parameter against free drug AUC (fAUC0–12) in plasma. The total AUC0–12in plasma was 4.56 ± 0.94 μg·h/ml with a meanfAUC0–12of 0.77 ± 0.14 μg·h/ml. The eravacycline concentrations in ELF and AM at 2, 4, 6, and 12 h were means ± the standard deviations (μg/ml) of 0.70 ± 0.30, 0.57 ± 0.20, 0.34 ± 0.16, and 0.25 ± 0.13 with a penetration ratio of 6.44 and 8.25 ± 4.55, 5.15 ± 1.25, 1.77 ± 0.64, and 1.42 ± 1.45 with a penetration ratio of 51.63, respectively. The eravacycline concentrations in the ELF and AM achieved greater levels than plasma by 6- and 50-fold, respectively, supporting further study of eravacycline for patients with respiratory infections.

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