scholarly journals Pharmacokinetics of chloroquine and primaquine in healthy volunteers

2022 ◽  
Vol 21 (1) ◽  
Author(s):  
André Daher ◽  
Douglas Pereira Pinto ◽  
Laís Bastos da Fonseca ◽  
Heliana Martins Pereira ◽  
Diego Medeiros Dias da Silva ◽  
...  
Keyword(s):  
Healthy Volunteers ◽  
Treatment Efficacy ◽  
Analytical Methods ◽  
Vivax Malaria ◽  
Plasma Concentrations ◽  
Open Data ◽  
Blood Levels ◽  
Pharmacokinetic Data ◽  
Open Label ◽  
Serious Adverse Events

Abstract Background Vivax malaria is a neglected disease. There is an irrefutable need for better treatments with higher acceptability and efficacy. The treatment efficacy is influenced by many factors, including bioavailability. Hence, a straightforward strategy to improve vivax malaria treatment efficacy is the deployment of good quality formulations of primaquine and chloroquine. As these treatments were developed more than 70 years ago, many of the available data on blood levels of both drugs are based on obsolete analytical methodologies or pharmaceutical formulations, which are not available anymore. Herein, the results of three bioequivalence studies are presented, providing individual pharmacokinetic data on chloroquine and primaquine of more than a hundred healthy volunteers and using up-to-date analytical methods. Methods Three trials were designed as a single centre, randomized, single dose, open label, fasting, crossover bioequivalence studies comparing a new coated chloroquine tablet to the uncoated tablet, and 5 and 15 mg primaquine formulations to either an international reference product or the currently distributed tablets. Plasma concentrations of chloroquine and primaquine were measured using a validated HPLC–MS/MS method in accordance with current international regulatory requirements for bio-analytical methods. Results In total, a hundred eleven healthy volunteers of both genders were included in the three studies (n = 32; 30 and 56 respectively). No serious adverse events occurred. Drugs levels were measured in 5,520 blood samples. The estimated ratio of the geometric means of Cmax, AUC0-t and AUC0-inf of test and reference drugs and their 90% CI for chloroquine 150 mg, primaquine 15 mg and primaquine 5 mg were: 95.33% (89.18; 101.90), 86. 85% (82.61; 91.31), and 84.45% (76.95; 92.67); 93.28% (81.76; 106.41), 94.52% (86.13; 103.73) and 93.93% (85.83; 102.79); 97.44% (90.60; 104.78), 93.70% (87.04; 100.87) and 91.36% (85.27; 97.89), respectively. As Cmax and AUC0-t 90% CI were within the acceptance interval of 80–125% in all cases, the formulations tested were bioequivalent. Conclusions In conclusion, the three studies provided detailed chloroquine and primaquine pharmacokinetic data in accordance with current regulatory standards. Together with other open data initiatives, this individual data may increase the accuracy of pharmacokinetic models guiding best dose, new combinations, regimens and formulations to optimize the current chloroquine and primaquine treatments for vivax malaria. The data presented here may support the deployment of high-quality drugs and evidence-based public health policies.

scholarly journals Open-Label, Dose Escalation Study of the Safety and Pharmacokinetic Profile of Tefibazumab in Healthy Volunteers

2005 ◽  
Vol 49 (3) ◽  
pp. 959-962 ◽  
Author(s):  
Sandra Reilley ◽  
Eric Wenzel ◽  
Laurie Reynolds ◽  
Beth Bennett ◽  
Joseph M. Patti ◽  
...  
Keyword(s):  
Healthy Volunteers ◽  
Dose Escalation ◽  
Maximum Concentration ◽  
Dose Range ◽  
Plasma Concentrations ◽  
Open Label ◽  
Serious Adverse Events ◽  
Dose Escalation Study ◽  
Label Dose ◽  
The Mean

ABSTRACT Tefibazumab (Aurexis) is a humanized monoclonal antibody being evaluated as adjunctive therapy for the treatment of Staphylococcus aureus infections. This open-label, dose escalation study evaluated the safety and pharmacokinetics of tefibazumab in 19 healthy volunteers aged 18 to 69 years. Each subject received a single administration of tefibazumab at a dose of 2, 5, 10, or 20 mg/kg of body weight infused over 15 min. Plasma samples for pharmacokinetic assessments were obtained before infusion as well as 1, 6, 12, and 24 h and 3, 4, 7, 21, 28, 42, and 56 days after dosing. Plasma concentrations of tefibazumab were detected 1 h after the end of the infusion, with a mean maximum concentration of drug in serum (C max) of 59, 127, 252, and 492 μg/ml following doses of 2, 5, 10, and 20 mg/kg, respectively. The median time to maximum concentration of drug in serum (T max) was 1.0 h for each dose. The mean elimination half-life (t 1/2) was approximately 22 days. The volume of distribution (V) was 4.7, 6.7, 7.2, and 7.2 liters after doses of 2, 5, 10, and 20 mg/kg, respectively. Clearance (CL) was 6.0, 9.2, 10.2, and 9.9 ml/hr, respectively. At the highest dose, plasma levels of tefibazumab were >100 μg/ml for 21 days. On day 56, the mean plasma concentrations were 6.3, 10.0, 16.4, and 30.5 μg/ml for the 2, 5, 10, and 20 mg/kg doses, respectively. Tefibazumab exhibited linear kinetics across doses of 5, 10, and 20 mg/kg. No anti-tefibazumab antibodies were detected after dosing in any subject. There were no serious adverse events, and tefibazumab was well tolerated over the entire dose range.

scholarly journals Pharmacokinetics of a Novel Form of Biotin, Magnesium Biotinate, in Healthy Subjects (P06-027-19)

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Sara Perez Ojalvo ◽  
Sarah Sylla ◽  
James Komorowski
Keyword(s):  
Clinical Study ◽  
Peak Plasma ◽  
Plasma Concentrations ◽  
Area Under The Curve ◽  
Blood Levels ◽  
Pharmacokinetic Data ◽  
Open Label ◽  
Post Dose ◽  
Funding Sources ◽  
Study Results

Abstract Objectives Biotin, also known as vitamin B7, plays an important role in the metabolization of nutrients into energy. Magnesium biotinate (MgB) is a novel biotin compound that has been shown to be 40 times more soluble than D-Biotin. Preclinical evidence has shown that MgB is well absorbed into the bloodstream and tissues, particularly the brain, over time. The following pharmacokinetic study was carried out to further explore the absorption and bioavailability of MgB. Methods In an open-label clinical study, 30 healthy female subjects (18–45 years, BMI 18.0–29.9 kg/m2) were randomized to receive a single oral capsule containing one of the following doses of MgB (n = 10 per group): 1) 10 mg MgB, 2) 40 mg MgB, 3) 100 mg MgB. Serial blood samples were collected in K2-EDTA tubes at pre-dose (within 1 hour of dose) and at 0.5, 1.0, 1.5, 3.0 and 6.0 hours post-dose. Plasma samples were analyzed for biotin by LC/MS/MS. Pharmacokinetic data were calculated for each dose group. Results Study results showed that plasma biotin levels increased at 0.5, 1.0, 1.5, 3.0 and 6.0 hours post-dose for all groups. However, the largest biotin increase was seen in the 100 mg group (Figure 1). Peak plasma concentrations were observed as follows: 84.8 ng/mL 1 hour after a 10 mg dose, 214.6 ng/mL 1.5 hours after a 40 mg dose, and 508.5 ng/mL 1.5 hours after a 100 mg dose. Area under the curve values increased with increasing biotin dose level (10 mg: 210.0 ng*h/mL; 40 mg: 605.1 ng*h/mL; 100 mg: 1652.4 ng*h/mL). No adverse effects were observed. Conclusions Results from this single-dose pharmacokinetic clinical study demonstrate that magnesium biotinate is a bioavailable form of biotin, with increasing blood levels associated with increasing dose levels. Funding Sources This study was funded by JDS Therapeutics, LLC. Supporting Tables, Images and/or Graphs

scholarly journals Everolimus for the treatment of lymphangioleiomyomatosis: a phase II study

2015 ◽  
Vol 46 (3) ◽  
pp. 783-794 ◽  
Author(s):  
Hilary J. Goldberg ◽  
Sergio Harari ◽  
Vincent Cottin ◽  
Ivan O. Rosas ◽  
Elizabeth Peters ◽  
...  
Keyword(s):  
Lung Function ◽  
Adverse Events ◽  
Mammalian Target Of Rapamycin ◽  
Mtor Inhibitors ◽  
Collagen Iv ◽  
Blood Levels ◽  
Forced Expiration ◽  
Open Label ◽  
Serious Adverse Events ◽  
Cystic Lung

Lymphangioleiomyomatosis is a rare, progressive cystic lung disorder characterised by dysregulated activation of mammalian target of rapamycin (mTOR) signalling.This was a phase IIa, multicentre, open-label study of the mTOR inhibitor everolimus (2.5 mg·day−1 escalated to 10 mg·day−1) in 24 women with lymphangioleiomyomatosis. Primary endpoints were safety, pharmacokinetics and serum vascular endothelial growth factor-D (VEGF-D) levels; secondary endpoints were measures of lung function.Following 26 weeks of everolimus treatment, forced vital capacity exhibited stability, while forced expiration volume in 1 s improved from baseline, with mean changes (95% confidence interval) of 10 mL (−111–132) and 114 mL (11–217), respectively; 6-min walk distance improved by 47 m. Median VEGF-D and collagen IV levels decreased from baseline, from 1730 pg·mL−1 to 934.5 pg·mL−1, and 103 ng·mL−1 to 80.5 ng·mL−1, respectively. Adverse events were mostly grade 1−2; mouth ulceration, headache, nausea, stomatitis and fatigue were common. Serious adverse events suspected to be treatment related included peripheral oedema, pneumonia, cardiac failure and Pneumocystis jirovecii infection. Everolimus blood levels increased dose proportionally.In this study, everolimus improved some measures of lung function and exercise capacity and reduced serum VEGF-D and collagen IV. Side effects were generally consistent with known toxicities of mTOR inhibitors, although some were severe.

scholarly journals Effect of Thunbergia laurifolia Herbal Tea on Glucose Homeostasis in Healthy Volunteers: A Single-Arm Phase I Study

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Lukana Preechasuk ◽  
Pravit Akarasereenont ◽  
Ranida Boonrak ◽  
Onusa Thamsermsang ◽  
Busadee Pratumvinit ◽  
...  
Keyword(s):  
Adverse Effects ◽  
Healthy Volunteers ◽  
Glucose Homeostasis ◽  
Plasma Glucose ◽  
Fasting Plasma Glucose ◽  
Plasma Concentrations ◽  
Herbal Tea ◽  
Serious Adverse Events ◽  
Fasting Plasma ◽  
Thunbergia Laurifolia

Background. Thunbergia laurifolia (TL) is a commonly used herbal medicine in Thailand and in other Asian countries. TL has been approved as a Thai traditional medicine for detoxifying poisons, and the list of possible adverse effects includes hypoglycemia. TL showed hypoglycemic effect in animals possibly due to antioxidant effect and beta-cell preservation. However, the safety of TL herbal tea and its effects on glucose homeostasis have never been investigated in humans. Methods. Twenty healthy volunteers (10 men and 10 women) drank TL herbal tea 3 times/day for 2 weeks. Ten subjects took TL herbal tea 9 grams daily. After the safety of TL herbal tea was established, 10 more subjects took TL 12 grams daily. Clinical and biochemical tests were assessed at baseline and at 2 weeks. Results. Mean age was 34.9 ± 10.2 years, and mean body mass index was 27.5 ± 5.8 kg/m2. Baseline and posttreatment plasma concentrations were as follows: fasting plasma glucose (89 ± 6 vs. 89 ± 7 mg/dL), fructosamine (213 ± 32 vs. 212 ± 33 μmol/L), fasting insulin (8.8 [IQR: 5.9–18.4] vs. 10.4 [IQR: 7.4–15.2] μU/mL), HOMA-B (101.6 [IQR: 82.3–189.8] vs. 120.4 [IQR: 93.2–153.2]), and HOMA-IR (1.1 [IQR: 0.8–2.3] vs. 1.4 [IQR: 0.9–2.0]), all respectively. There were no significant changes in these parameters, including body weight, blood pressure, lipid profile, and C-reactive protein. No serious adverse events were observed during the study period. Conclusions. TL herbal tea at doses of 9 and 12 grams daily had good tolerability without any significant adverse effects on fasting plasma glucose level or other glucose homeostasis parameters measured.

scholarly journals Opposite Effects of Single-Dose and Multidose Administration of the Ethanol Extract of Danshen on CYP3A in Healthy Volunteers

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Furong Qiu ◽  
Jian Jiang ◽  
Yueming Ma ◽  
Guangji Wang ◽  
Chenglu Gao ◽  
...  
Keyword(s):  
Single Dose ◽  
Healthy Volunteers ◽  
Plasma Concentrations ◽  
In Vitro Study ◽  
Ethanol Extract ◽  
Tanshinone Iia ◽  
Open Label ◽  
The Mean

The aim of this study was to investigate the effect of single- and multidose administration of the ethanol extract of danshen on in vivo CYP3A activity in healthy volunteers. A sequential, open-label, and three-period pharmacokinetic interaction study design was used based on 12 healthy male individuals. The plasma concentrations of midazolam and its metabolite 1-hydroxymidazolam were measured. Treatment with single dose of the extract caused the meanCmaxof midazolam to increase by 87% compared with control. After 10 days of the danshen extract intake, the mean AUC0–12,Cmax, andt1/2of midazolam were decreased by 79.9%, 66.6%, and 43.8%, respectively. The mean clearance of midazolam was increased by 501.6% compared with control. The in vitro study showed that dihydrotanshinone I in the extract could inhibit CYP3A, while tanshinone IIA and cryptotanshinone could induce CYP3A. In conclusion, a single-dose administration of the danshen extract can inhibit intestinal CYP3A, but multidose administration can induce intestinal and hepatic CYP3A.

Effect of food on the pharmacokinetics of dronabinol oral solution versus dronabinol capsules in healthy volunteers.

2016 ◽  
Vol 34 (26_suppl) ◽  
pp. 199-199
Author(s):  
Christina Cognata Smith ◽  
D. Alexander Oh ◽  
Neha Parikh ◽  
Varun Khurana ◽  
Santosh Vetticaden
Keyword(s):  
Healthy Volunteers ◽  
Therapeutic Benefit ◽  
Oral Solution ◽  
Individual Variability ◽  
Pharmacokinetic Data ◽  
Inadequate Response ◽  
Open Label ◽  
Post Dose ◽  
Solution Versus ◽  
Fed State

199 Background: Dronabinol, a pharmaceutical tetrahydrocannabinol (THC), capsule is approved for anorexia associated with weight loss in patients with AIDS and for cancer chemotherapy-induced nausea/vomiting in patients with inadequate response to conventional antiemetic therapy. Food effects on absorption and bioavailability of a new dronabinol oral solution was compared with marketed capsules. Methods: In an open-label, single-dose, 3-period crossover study, healthy volunteers were randomized to receive dronabinol oral solution 4.25 mg (fed) or dronabinol capsule 5 mg (fed or fasted), after a 7-day washout period. Doses were administered under a fasted (overnight) or fed state (high-fat/calorie meal 30 minutes pre-dose). Plasma pharmacokinetics was evaluated for dronabinol and the major metabolite, 11-OH-Δ9-THC. Results: Pharmacokinetic data of 54 volunteers were analyzed. In the fed state, initial dronabinol absorption was rapid with oral solution versus capsules (mean Tlag, 0.15 vs 2.02 h), and 100% and 15% of volunteers receiving oral solution and capsules, respectively, had detectable plasma dronabinol levels 30 minutes post-dose. Inter-individual variability in plasma dronabinol concentrations during early absorption was less with oral dronabinol solution (%CV: 82.79%, 83.94%, and 90.68%) versus capsules (%CV: 318.54%, 250.33%, and 182.01%) observed at 0.5, 1, and 2 h, respectively, after dosing. Food increased mean AUC0-t similarly for dronabinol oral solution and capsules, versus capsules with fasting, increasing exposure to oral solution and capsules 2.1- to 2.4-fold. Mean Tmax was similarly delayed for dronabinol oral solution (7.7 h) and capsules (5.6 h) with food relative to fasting (1.7 h). On the basis of 11-OH-Δ9-THC plasma levels, AUC0-t up to 48 h postdose and AUC0-inf were found to be similar for the oral solution and capsules under fed conditions. Conclusions: An appreciable food effect was observed for dronabinol oral solution and capsules. Dronabinol oral solution may offer therapeutic benefit to patients given its rapid absorption and lower inter-individual variability compared with dronabinol capsules. Clinical trial information: NCT01448772.

scholarly journals Comparative single-dose bioavailability study of two 10 mg Zolpidem tablet formulations in healthy volunteers

2019 ◽  
Vol 65 (01) ◽  
pp. 11-17
Author(s):  
Dimce Zafirov ◽  
Jasmina Trojacanec ◽  
Dragica Zendelovska ◽  
Nikola Kolovcevski ◽  
Bojan Labachevski
Keyword(s):  
Single Dose ◽  
Healthy Volunteers ◽  
Plasma Concentrations ◽  
Bioequivalence Study ◽  
Relative Bioavailability ◽  
Serious Adverse Events ◽  
Test Formulation ◽  
Single Oral Administration ◽  
Hypnotic Agent ◽  
Bioavailability Study

Zolpidem is a hypnotic agent with a chemical structure unrelated to benzodiazepines, barbiturates, pyrrolopyrazines, pyrazolopyrimidines or other drugs with known hypnotic properties. Zolpidem as conventional tablets is used as a hypnotic agent in the short-term management of insomnia, generally for periods not exceeding 7–10 days in duration. The objective of this study was to evaluate and compare the relative bioavailability, and therefore the bioequivalence of Zolpidem 10 mg test formulation versus a reference Zolpidem 10 mg formulation, following a single dose administration under fasting conditions The study was a single center, open, single dose, randomized, two - way crossover study in healthy male volunteers with a wash - out period of one week between study periods. Twenty-eight male healthy volunteers, aged 20-49 years were included into study. Blood samples for determination of zolpidem plasma concentrations were withdraw at 0 (pre-drug administration), 0.33, 0.66, 1, 1.33, 1.66, 2, 2.5, 3, 3.5, 4, 5, 6, 8, 10, 12, 16 and 24 hours post-drug. The zolpidem concentrations in plasma were determined with HPLC, using fluorescence detection. The test formulation of zolpidem, dosed at 10 mg is bioequivalent for primary zolpidem parameters (Cmax, AUC0-t and AUC0-∞) to the reference formulation after a single oral administration of 10 mg zolpidem. Both medications are well tolerated with no serious adverse events. Thus, in view of the clinical use, both formulations are exchangeable without restrictions. Keywords: Zolpidem, bioavailability, bioequivalence study, single-dose

scholarly journals Pharmacokinetics and Safety Profile of the Human Anti-Pseudomonas aeruginosa Serotype O11 Immunoglobulin M Monoclonal Antibody KBPA-101 in Healthy Volunteers

2009 ◽  
Vol 53 (8) ◽  
pp. 3442-3446 ◽  
Author(s):  
Hedvika Lazar ◽  
Michael P. Horn ◽  
Adrian W. Zuercher ◽  
Martin A. Imboden ◽  
Peter Durrer ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Pseudomonas Aeruginosa ◽  
Body Weight ◽  
Healthy Volunteers ◽  
Human Monoclonal Antibody ◽  
Dose Range ◽  
Plasma Concentrations ◽  
Immunoglobulin M ◽  
Serious Adverse Events ◽  
The Mean

ABSTRACT KBPA-101 is a human monoclonal antibody of the immunoglobulin M isotype, which is directed against the O-polysaccharide moiety of Pseudomonas aeruginosa serotype O11. This double-blind, dose escalation study evaluated the safety and pharmacokinetics of KBPA-101 in 32 healthy volunteers aged 19 to 46 years. Each subject received a single intravenous infusion of KBPA-101 at a dose of 0.1, 0.4, 1.2, or 4 mg/kg of body weight or placebo infused over 2 h. Plasma samples for pharmacokinetic assessments were taken before infusion as well as 0.25, 0.5, 1, 2, 2.5, 4, 6, 8, 12, 24, 36, and 48 h and 4, 7, 10, and 14 days after start of dosing. Plasma concentrations of KBPA-101 were detected with mean maximum concentrations of drug in plasma of 1,877, 7,571, 24,923, and 83,197 ng/ml following doses of 0.1, 0.4, 1.2, and 4.0 mg/kg body weight, respectively. The mean elimination half-life was between 70 and 95 h. The mean volume of distribution was between 4.76 and 5.47 liters. Clearance ranged between 0.039 and 0.120 liters/h. At the highest dose of 4.0 mg/kg, plasma KBPA-101 levels were greater than 5,000 ng/ml for 14 days. KBPA-101 exhibited linear kinetics across all doses. No anti-KBPA-101 antibodies were detected after dosing in any subject. Overall, the human monoclonal antibody KBPA-101 was well tolerated over the entire dose range in healthy volunteers, and no serious adverse events have been reported.

Pharmacokinetics and investigation of optimal dose ertapenem in intermittent hemodialysis patients

2018 ◽  
Vol 34 (10) ◽  
pp. 1766-1772 ◽  
Author(s):  
Lama M Hsaiky ◽  
Francine D Salinitri ◽  
Judy Wong ◽  
Sin-Ling T Jennings ◽  
Neha H Desai ◽  
...  
Keyword(s):  
Half Life ◽  
Plasma Concentrations ◽  
Area Under The Curve ◽  
Optimal Dose ◽  
Hemodialysis Patients ◽  
Pharmacokinetic Parameters ◽  
Intermittent Hemodialysis ◽  
Pharmacokinetic Studies ◽  
Open Label ◽  
Serious Adverse Events

Abstract Background Previous pharmacokinetic studies demonstrated an increase in serum ertapenem concentrations with decreasing kidney function, including patients receiving renal replacement therapy. This study evaluated the pharmacokinetic parameters of ertapenem in patients receiving hemodialysis. Methods This prospective, single-center, open-label study examined the pharmacokinetics of a single intravenous (IV) dose of ertapenem 1 g in seven hospitalized noninfected patients undergoing hemodialysis. Blood samples were collected prior to ertapenem administration and at 0.5, 1, 2, 6, 12 and 48 hours (h) after administration. Ertapenem concentrations were determined by validated liquid chromatography mass spectrometry assay. Results Following an IV bolus of 1 g ertapenem, plasma concentrations declined relatively slowly with a mean ±standard deviation (SD) elimination half-life of 19.3 ±6.6 h. Plasma concentrations were similar in all subjects, with maximum mean plasma concentration observed of 343±48 µg/mL postdose. The mean ±SD values for systemic plasma clearance (CL) and volume of distribution at steady state (Vss) were 2±0.5 mL/min and 3295±1187 mL, respectively. The area under the curve for 0 h–∞ (AUCinf) was 7494 ±1424 h•µg/mL. No gender effect was observed and no serious adverse events were reported. Conclusions Ertapenem half-life was prolonged in hemodialysis patients. Considering the nonrenal clearance and the expected 70% removal with high-efficacy hemodialysis, the dose of 1 g ertapenem, three times weekly, after hemodialysis may produce pharmacodynamically sufficient exposure for potential antimicrobial efficacy. Further studies are warranted to assess the clinical efficacy and safety of this dose with prolonged duration of therapy.

scholarly journals Pharmacokinetic Properties of Single-Dose Primaquine in Papua New Guinean Children: Feasibility of Abbreviated High-Dose Regimens for Radical Cure of Vivax Malaria

2013 ◽  
Vol 58 (1) ◽  
pp. 432-439 ◽  
Author(s):  
Brioni R. Moore ◽  
Sam Salman ◽  
John Benjamin ◽  
Madhu Page-Sharp ◽  
Leanne J. Robinson ◽  
...  
Keyword(s):  
Single Dose ◽  
Vivax Malaria ◽  
Venous Blood ◽  
Plasma Concentrations ◽  
Volume Of Distribution ◽  
Population Pharmacokinetic ◽  
High Dose ◽  
Pharmacokinetic Data ◽  
Radical Cure ◽  
Papua New Guinean

ABSTRACTSince conventional 14-day primaquine (PMQ) radical cure of vivax malaria is associated with poor compliance, and as total dose, not therapy duration, determines efficacy, a preliminary pharmacokinetic study of two doses (0.5 and 1.0 mg/kg of body weight) was conducted in 28 healthy glucose-6-phosphate dehydrogenase-normal Papua New Guinean children, aged 5 to 12 years, to facilitate development of abbreviated high-dose regimens. Dosing was with food and was directly observed, and venous blood samples were drawn during a 168-h postdose period. Detailed safety monitoring was performed for hepatorenal function and hemoglobin and methemoglobin concentrations. Plasma concentrations of PMQ and its metabolite carboxyprimaquine (CPMQ) were determined by liquid chromatography-mass spectrometry and analyzed using population pharmacokinetic methods. The derived models were used in simulations. Both single-dose regimens were well tolerated with no changes in safety parameters. The mean PMQ central volume of distribution and clearance relative to bioavailability (200 liters/70 kg and 24.6 liters/h/70 kg) were within published ranges for adults. The median predicted maximal concentrations (Cmax) for both PMQ and CPMQ after the last dose of a 1.0 mg/kg 7-day PMQ regimen were approximately double those at the end of 14 days of 0.5 mg/kg daily, while a regimen of 1.0 mg/kg twice daily resulted in a 2.38 and 3.33 times higherCmaxfor PMQ and CPMQ, respectively. All predicted medianCmaxconcentrations were within ranges for adult high-dose studies that also showed acceptable safety and tolerability. The present pharmacokinetic data, the first for PMQ in children, show that further studies of abbreviated high-dose regimens are feasible in this age group.

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