Pharmacology

Bioavailability

The fraction of an administered dose that reaches systemic circulation unchanged.

Definition

Oral bioavailability of peptides is generally very low due to GI degradation. Subcutaneous injection bypasses this. Semaglutide tablets (Rybelsus) achieve oral bioavailability using an absorption-enhancer formulation.

Related terms

Half-LifeThe time required for plasma drug concentration to fall by 50%.
Subcutaneous Injection (SC)Injection into the layer of fat beneath the skin — the most common route for peptide administration.

Back to the full peptide glossary.