The four letters of ADME sum up a molecule's journey. Absorption: how it moves from the site of administration into the blood. Distribution: which tissues it reaches and how much binds to plasma proteins. Metabolism: how it is transformed or broken down. Elimination: how it leaves, mainly via the kidney or bile.
That journey yields the parameters that describe a substance: maximum concentration (Cmax) and the time to reach it (Tmax), area under the curve (AUC, total exposure), volume of distribution, clearance and half-life.
Peptides have a characteristic pharmacokinetic profile: they are broken down by proteolysis rather than by the classic liver enzymes, they barely interact with other drugs through that route, and small ones are cleared quickly by the kidney unless they are designed to avoid it.
The same compound can look very active or inactive depending on the exposure pattern of the study. Pharmacokinetics explains why two protocols with the same total amount give different results.
Related terms
Learn it in depth at the Peptide University
- Pharmacokinetics: ADME and parameters · Module 2
- Chemical modifications: from the natural sequence to the analog · Module 1
- Precautions, interactions and monitoring · Module 10
- Hierarchy of evidence and development phases · Module 13
- Common biases and scaling between species · Module 13
Definition for educational and scientific purposes. It is not medical advice or a recommendation for use. NeoPeptidos products are sold labelled for research use only (RUO).