Pharmacokinetic / pharmacodynamics (PK/PD) modeling, an integral component of the drug development process, is a mathematical technique for predicting the effect and efficacy of drug dosing over time. Broadly speaking, pharmacokinetic models describe how the body reacts to a drug in terms of absorption, distribution, metabolism, and excretion. Pharmacodynamic models describe how a drug affects the body by linking the drug concentration to an efficacy (or safety) metric. A well-characterized PK/PD model is an important tool in guiding the design of future experiments and trials.
PK/PD Modeling Services
- Development of PK/PD strategy as part of the drug development plan
- Design of standalone Pharmacokinetic(PK) studies and sub-studies
- Sample size and power calculations
- Generation of randomization codes
- Preparation of analysis plans
- Compartmental and non-compartmental pharmacokinetic analysis
- Pharmacodynamic analysis
- Assessment of PK/PD relationship
- Assessment of Bioequivalence/Bioavailability
- Drug interaction evaluations
• PK = Pharmacokinetics
– relationship between the dose administered and the changes in the drug concentration in the body with time. (Measured by drug concentration in blood, plasma, tissue)
• PD = Pharmacodynamics
– relationship between drug concentration and its pharmacologic effect (Effects of a drug on the body / disease)
• PK is a determinant of PD
Pharmacokinetics is the study of what the body does to the drug.
Pharmacodynamics is the study of what the drug does to the body.
- Dose-Response Relationships
- Therapeutic Index
• The numbers of receptors
• The willingness of a drug to associate with a receptor = receptor affinity
• The presence of other compounds competing for the binding site on the receptor = agonist /antagonist
• The concentration of the free drug in the vicinity of the receptor = pharmacokinetics
• The therapeutic index (also known as therapeutic ratio), is a comparison of the amount of a therapeutic agent that causes the therapeutic effect to the amount that causes death (in animal studies) or toxicity (in human studies).
PK-PD Changes in Critical Illness
• Circulatory Failure
• Hepatic Failure
• Renal Failure
• Systemic Inflammatory Response Syndrome
• Changes in Receptors in Acute Illness
• Protein Binding