This talk will introduce the concept of using virtual patients, generated by quantitative systems pharmacology models that can be used as ensembles in teaching therapeutic decision-making to pharmacy students. The concept of model validation will be reviewed and aligned with the concept of model use. In an education setting the purpose of generating a virtual […]

Steve Duffull
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Author Archive | Steve Duffull
On mass balance and the use-reuse of the rate constant matrix in pharmacokinetics
January 21, 2022
Authors Stephen Duffull
Affiliations Otago Pharmacometrics Group, School of Pharmacy, University of Otago, New Zealand.
Presentation type Oral
Presenters Steve Duffull
Introduction Assurance of mass balance is a critical part of pharmacometric model formulation (i.e. model creation and coding). In many cases, for simple mamillary compartmental models this can be assessed informally. However, in more complicated models (e.g. physiologically based models) the proof of mass balance can be more complicated. A method to evaluate mass balance […]
Issues with virtual populations when applied to nonlinear QSP models
January 10, 2021
Authors Stephen Duffull(1), Abhishek Gulati(2)
Affiliations 1. Otago Pharmacometrics Group, School of Pharmacy, University of Otago, New Zealand. 2. Clinical Pharmacology & Exploratory Development, Astellas Pharma Global Development Inc., Northbrook, Illinois, USA
Presentation type Oral
Presenters Steve Duffull
Introduction Quantitative systems pharmacology (QSP) models describe the clinical pharmacological properties of a drug. They are typically described as systems of linear mass-balance and nonlinear mass-action of drugs. One of the purposes of QSP models is to simulate potential outcomes from virtual clinical trials. This approach is predicated on generating virtual populations of patients (a […]
PAGANZ Workshop: CellML and OpenCOR
January 15, 2019
Authors Soroush Safaei (1), Steve Duffull (2)
Affiliations (1) Auckland Bioengineering Institute, University of Auckland (2) Otago Pharmacometrics Group, School of Pharmacy University of Otago
Presentation type Oral
Presenters Soroush Safaei
Over the past 10 year quantitative systems pharmacology has become an integral part of pharmacometrics. While the models and methods used in a QSP framework are novel to pharmacometricians they have been well established in the disciplines of systems biology and bioengineering. Software (e.g. CellML, SBML, …) for specifying models and enabling simulations from models […]
Dose banding- weighing up benefits vs risks
November 29, 2018
Authors Stephen Duffull
Affiliations Otago Pharmacometrics Group, School of Pharmacy, University of Otago
Presentation type Oral
Presenters Stephen Duffull
Background: Dose banding is the allocation of patients into a pre-specified dose group based on the patient’s value of a covariate and is commonly recommended in drug labels. The simplest form of dose banding assigns all patients to receive the same dose irrespective of their characteristics. The corollary to “one dose fits all” is where […]
An approach to evaluating mass and energy balance of pharmacokinetic systems using bond graph theory
January 24, 2018
Authors Stephen Duffull (1), Soroush Safaei (2), Peter Hunter(2)
Affiliations (1) Otago Pharmacometrics Group, School of Pharmacy, University of Otago; (2) Auckland Bioengineering Institute, University of Auckland
Presentation type Oral
Presenters Stephen Duffull
Introduction: Quantitative systems pharmacology models are used in PKPD and pharmacometrics to describe the effects of drugs as modulators of system behaviour. In most cases the systems that are described in these models can be constructed of modular units that can be assembled en-masse to create the overall system. An example of a modular component […]
Development and application of a pharmacokinetic model for the glycation of albumin
January 30, 2012
Authors Oskar Alsk
Affiliations (1) Department of Pharmaceutical Biosciences, Division of Pharmacokinetics and Drug Therapy, Faculty of Pharmacy, Uppsala University, Sweden, (2) School of Pharmacy, University of Otago, Dunedin, New Zealand
Presentation type Oral
Presenters Steve Duffull
Background Glycated haemoglobin, HbA1c, is used commonly as a marker for glycaemic control. In patients with chronic kidney disease (CKD) red blood cells (RBCs) are removed faster from the circulation, giving less time for glycation of haemoglobin to occur [1]. Thus, HbA1c concentrations are falsely lowered in these patients. Glycated albumin (GA) has been suggested […]
Evaluation of an optimal design for examining melphalan pharmacokinetics in patients with multiple myeloma
December 23, 2009
Authors SB Duffull (1), G Hegarty (1), CE Nath (2), PJ Shaw (2,4), J Trotman (3,4)
Affiliations (1) School of Pharmacy, University of Otago, Dunedin, New Zealand, (2) The Children
Presentation type Oral
Background: The optimal design of population pharmacokinetics allows parameter estimation with minimum variance and reduced cost by identifying (1) the minimum number of blood samples required from each subject, (2) the optimal blood sampling times and (3) the minimum number of subjects required. Aim: To evaluate the results of an optimal design experiment that was […]