# Pharmacokinetic and pharmacodynamic modelling

Source: https://onco.cc/technologies/pkpd-modelling/  
OnCo record `pkpd-modelling` (Technology). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Equations that describe how a drug's concentration rises and falls in the body and how that concentration translates into effect and toxicity; the reason doses are given per square metre, why some drugs are infused over days, and how children's doses are set.

## Summary

Compartmental pharmacokinetic models describe absorption, distribution and clearance; pharmacodynamic models relate exposure to effect. In oncology they underpin body-surface-area and weight-based dosing, carboplatin dosing by kidney function (the Calvert formula), therapeutic drug monitoring of methotrexate and busulfan, the design of continuous infusions and depot formulations, and the exposure-response analyses that regulators now expect. Population models with individual variability explain why fixed doses of some antibodies work, and physiologically based models scale doses to children and to organ impairment.

## Fields

- Kind: Technology
- Status: established
- Last checked: 2026-09-17
- Tags: mathematical-model
- Principle: Drug concentration follows first-order transfer between compartments; effect is a saturable (Emax) function of concentration; population variability is modelled as random effects around typical parameters.
- Since: 1970
- Strengths: Basis of every dosing regimen; Enables therapeutic drug monitoring; Extends to children and organ impairment
- Limitations: Effect models are often empirical; Tumour drug penetration poorly captured; Individual prediction remains uncertain

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Pharmacokinetics
- Calvert formula, 1989: https://doi.org/10.1200/JCO.1989.7.11.1748

## Connected records

- fronts: [AI & Computation](https://onco.cc/fronts/ai-computation/), [Drug Discovery Platforms](https://onco.cc/fronts/drug-discovery/)
- technologies: [Body-surface-area dosing](https://onco.cc/technologies/body-surface-area-dosing/), [Pharmacogenomic testing before chemotherapy](https://onco.cc/technologies/oncology-pharmacogenomics/), [Quantitative systems pharmacology (QSP)](https://onco.cc/technologies/quantitative-systems-pharmacology/)
- drugs: [Busulfan](https://onco.cc/drugs/busulfan/), [Carboplatin](https://onco.cc/drugs/carboplatin/), [Methotrexate](https://onco.cc/drugs/methotrexate/)

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