title: Optimal blood sampling time windows for parameter estimation using a population approach: design of a phase II clinical trial.
abstract: The objective of this paper is to determine optimal blood sampling time windows for the estimation of pharmacokinetic (PK) parameters by a population approach within the clinical constraints. A population PK model was developed to describe a reference phase II PK dataset. Using this model and the parameter estimates, D-optimal sampling times were determined by optimising the determinant of the population Fisher information matrix (PFIM) using PFIM_ _M 1.2 and the modified Fedorov exchange algorithm. Optimal sampling time windows were then determined by allowing the D-optimal windows design to result in a specified level of efficiency when compared to the fixed-times D-optimal design. The best results were obtained when K(a) and IIV on K(a) were fixed. Windows were determined using this approach assuming 90% level of efficiency and uniform sample distribution. Four optimal sampling time windows were determined as follow: at trough between 22 h and new drug administration; between 2 and 4 h after dose for all patients; and for 1/3 of the patients only 2 sampling time windows between 4 and 10 h after dose, equal to [4 h-5 h 05] and [9 h 10-10 h]. This work permitted the determination of an optimal design, with suitable sampling time windows which was then evaluated by simulations. The sampling time windows will be used to define the sampling schedule in a prospective phase II study.
authors.affiliation: School of Pharmacy and Pharmaceutical Sciences, University of Manchester, Oxford road, Manchester, M13 9PL, United Kingdom.
authors.forename: Marylore
authors.initials: M
authors.lastname: Chenel
authors.forename: Kayode
authors.initials: K
authors.lastname: Ogungbenro
authors.forename: Vincent
authors.initials: V
authors.lastname: Duval
authors.forename: Christian
authors.initials: C
authors.lastname: Laveille
authors.forename: Roeline
authors.initials: R
authors.lastname: Jochemsen
authors.forename: Leon
authors.initials: L
authors.lastname: Aarons
mesh_terms: D000284:Administration, Oral; D000465:Algorithms; D001800:Blood Specimen Collection; D017322:Clinical Trials, Phase II as Topic / Q000379:methods*; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D006801:Humans; D010599:Pharmacokinetics; D011446:Prospective Studies; D012107:Research Design; D013997:Time Factors