PK/PD in Medicine: Amiodarone

Amiodarone is an antiarrhythmic drug indicated for treatment and prophylaxis of ventricular fibrillation (VF)* and hemodynamically unstable congestive ventricular tachycardia (VT)* Pharmacology: Amiodarone is a class III antiarrhythmic drug. Mechanism : Inhibition of potassium rectifier currents responsible for repolarizing the heart during phase 3 of cardiac action potential. K+ channel-blocking effect results in increased action…

The Hollow Fiber Infection Model in Anti-Bacterial Drug Discovery and Development

Ramesh Jayaraman, DoseQuantics Consulting In anti-bacterial drug discovery and development, preclinical animal models of infection have played a pivotal role in evaluating the translational potential of drug candidates. Drug regulatory agencies review pharmacology data from preclinical animal models of infection for understanding the pharmacokinetic/pharmacodynamic (PK/PD) basis for setting efficacious dose and regimens for phase 2…

The concept of in vitro Area Under the Concentration Time Curve (AUC) in drug discovery

In drug discovery, in vitro pharmacology studies are fundamental in assessing a drug candidate’s intrinsic efficacy (Emax,activation or Imax,inhibition) and potency (EC50activation or IC50inhibition) on its pharmacological (drug) target outside the cells (binding and inhibiting or activating the target’s activity e.g. enzyme and receptor assays) and inside the cells (functional assays such as cell division, growth, inhibition,…

The Pharmaceutical Industry in Society

As the saying goes health is wealth. As long as people are healthy, physically and mentally, all is well. This is the ideal situation. However, the reality is far from this. Many people, unfortunately, are struck by illnesses that are life threatening or chronically debilitating, such as infection, cancer, diabetes, arthritis, hypertension, neurological, liver or…

Informed Experimental Design in Quantitative Pharmacology

An in vivo study, be it pharmacokinetics (PK), pharmacodynamics (PD), or pharmacokinetic/pharmacodynamic (PK/PD), should be designed to yield data that enables a decision to be made in drug discovery projects. This is particularly important as in vivo studies can be lengthy and often expensive. Poorly designed experiments may yield data that can be un-interpretable, incomplete…

Physiologically Based Pharmacokinetic (PBPK) Modelling in Drug Discovery and Development

Physiologically based pharmacokinetics (PBPK) describes the pharmacokinetics (PK) of a drug by integrating its physicochemical and in vitro ADME properties (drug specific) with physiological parameters (system specific) of the body. This is known as the” bottom up” approach (mechanistic), the opposite of empirical description of PK (sum of exponentials/compartments) known as “top down” approach. The mechanistic…

Physiologically Based Pharmacokinetic (PBPK) Modelling: Testing a Model

Ramesh Jayaraman, DoseQuantics Consulting Pvt Ltd The strength of a PK model is evaluated by its ability to predict the behavior of the drug at a dose or regimen that is different from the dose for which the model was developed. When the model successfully predicts PK across dose levels or regimens its robustness and…

Physiologically Based Pharmacokinetics (PBPK)

Physiologically based pharmacokinetics (PBPK) describes the pharmacokinetics (PK) of a drug by integrating its physicochemical and in vitro ADME properties (drug specific) with physiological parameters (system specific) of the body. This is known as the ”bottom up” approach (mechanistic), the opposite of empirical description of PK (sum of exponentials/compartments) known as “top down” approach. The…

What is a Lead Molecule?

Most often a Lead is determined based on meeting project criteria for But, a vital component seems to be missing in this set of criteria – Efficacy and PK/PD OR is not given importance. When all the above set criteria do not translate to efficacy (pharmacological effect/Pharmacodynamics) or safety, it suggests that there is no…

Pacritinib (VONJO) shows a relationship between objective response and meaningful clinical benefit in Myelofibrosis patients

Ramesh Jayaraman, DoseQuantics Consulting, September 12th 2025 The true worth of an anti-cancer drug is measured not just by its ability to reduce the cancer burden aka objective response (reduction in tumor size, prevention of metastasis) but the relationship between the reduction in cancer burden and the increase in meaningful clinical benefit (increase in overall survival…