In this episode I discuss different algorithms used for pharmacometrics modeling. I describe difference between maximum likelihood and expectation maximization methods. I review the FO and FOCEI maximum likelihood algorithms. I then review SAEM, IMP, and QRPEM expectation maximization algorithms that are available. I conclude with an brief explanation of the difference between parameter estimation…

In this episode I discuss my experience as an independent consultant in the clinical pharmacology and pharmacometrics space. I talk about how I got from high school to become a consultant. I touched on the many different activities I do as an independent consultant. I shared a bit about how I handle compensation with clients…

In this episode I discuss using nlmixr for population PK modeling in R. I give an overview of the software package, describe the installation process, and walk through a simple example. Overall, nlmixr is a nice package that can be used for most modeling activities you encounter. It eliminates the need for a license since…

In this episode I discuss power calculations using the R package PowerTOST. I gave an introduction to power calculations and the statistical premise. I reviewed bioequivalence study designs that are commonly used for generic drug development, food effect evaluation, and drug-drug interaction studies. Links discussed in the show: PowerTOST R package PowerTOST instructions (scroll down…

In this episode I share a couple short clips from my conversation with Chad Briscoe and Greg Austin from BioTalk Unzipped (http://www.biotalkunzipped.com). We chat about a variety of topics including artificial intelligence and challenges with cell therapy development. You can hear the entire conversation on the BioTalk Unizipped podcast or YouTube channel in January. For…

In this episode I discuss toxicokinetic analysis. This is the analysis of exposure data to support animal toxicology studies. I review the purpose of toxicology studies and how exposure metrics are used. Then I discuss different blood sampling schemes, and how to calculate exposure parameters for both full profiles and mean profiles. Links discussed in…

This episode is a discussion of steady state pharmacokinetics. Steady state occurs when the amount of drug input is equivalent to the amount of drug elimination in a dosing interval. I discuss some key PK parameters at steady state and how to use them. I also discuss different methods of confirming that you have reached…

In this episode I talk about dose proportionality, which is a surrogate for determining if we have linear clearance across a range of dose levels. I discuss 3 different methods that people use to determine dose proportionality along with a recommendation to use the power model method. Links discussed in the show: Power model method…

This episode is a discussion of covariate search methods. I give definitions of covariates and predictors, and then I describe 3 different covariate search methods. For each method I describe the pros and cons associated with each one, including bias and time limitations. Links discussed in the show: Evaluation of the Boruta method for covariate…

In this episode I describe stimulatory indirect response PK-PD models. I describe how they work, how to set up the dataset for NONMEM, and how to code the model in NONMEM. This is the last of 4 episodes on different PK-PD models. Links discussed in the show: Indirect response PK-PD model equations Example NONMEM code…