title: Optimal designs for population pharmacokinetic studies of oral artesunate in patients with uncomplicated falciparum malaria.
abstract: BACKGROUND
  Currently, population pharmacokinetic (PK) studies of anti-malarial drugs are designed primarily by the logistical and ethical constraints of taking blood samples from patients, and the statistical models that are fitted to the data are not formally considered. This could lead to imprecise estimates of the target PK parameters, and/or designs insufficient to estimate all of the parameters. Optimal design methodology has been developed to determine blood sampling schedules that will yield precise parameter estimates within the practical constraints of sampling the study populations. In this work optimal design methods were used to determine sampling designs for typical future population PK studies of dihydroartemisinin, the principal biologically active metabolite of oral artesunate.
  
  
  METHODS
  Optimal designs were derived using freely available software and were based on appropriate structural PK models from an analysis of data or the literature and key sampling constraints identified in a questionnaire sent to active malaria researchers (3-4 samples per patient, at least 15 minutes between samples). The derived optimal designs were then evaluated via simulation-estimation.
  
  
  RESULTS
  The derived optimal sampling windows were 17 to 29 minutes, 30 to 57 minutes, 2.5 to 3.7 hours and 5.8 to 6.6 hours for non-pregnant adults; 16 to 29 minutes, 31 minutes to 1 hour, 2.0 to 3.4 hours and 5.5 to 6.6 hours for designs with non-pregnant adults and children and 35 to 59 minutes, 1.2 to 3.4 hours, 3.4 to 4.9 hours and 6.0 to 8.0 hours for pregnant women. The optimal designs resulted in acceptable precision of the PK parameters.
  
  
  CONCLUSIONS
  The proposed sampling designs in this paper are robust and efficient and should be considered in future PK studies of oral artesunate where only three or four blood samples can be collected.
authors: Centre for Molecular, Environmental, Genetic and Analytic Epidemiology, School of Population Health, The University of Melbourne, Melbourne, Australia. kjamsen@pgrad.unimelb.edu.au
authors: Kris M
authors: KM
authors: Jamsen
authors: Stephen B
authors: SB
authors: Duffull
authors: Joel
authors: J
authors: Tarning
authors: Niklas
authors: N
authors: Lindegardh
authors: Nicholas J
authors: NJ
authors: White
authors: Julie A
authors: JA
authors: Simpson
mesh_terms: D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D000962:Antimalarials / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D037621:Artemisinins / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D000077332:Artesunate; D002648:Child; D002675:Child, Preschool; D003198:Computer Simulation; D005260:Female; D006801:Humans; D007223:Infant; D016778:Malaria, Falciparum / Q000188:drug therapy*; D015233:Models, Statistical; D011247:Pregnancy; D011795:Surveys and Questionnaires; D055815:Young Adult
chemical_list: D000962:Antimalarials; D037621:Artemisinins; D000077332:Artesunate