Plasma protein binding

Plasma protein binding defines the degree of binding of a drug to plasma proteins.

Plasma protein binding is a key characteristic of antibiotics since it affects both their pharmacokinetics and pharmacodynamics. In highly bound antibiotics, simple minimum inhibitory concentration (MIC) testing in protein-free standard medium does not reflect activity in patients. Protein binding can be measured by different methods, e.g. equilibrium dialysis (reference method), ultrafiltration, ultracentrifugation. The two major plasma proteins that bind antibiotics are serum albumin and α1-acid glycoprotein.

Protein Binding of Antimicrobials: Methods for Quantification and for Investigation of its Impact on Bacterial Killing (The AAPS Journal, 2009)

Effect of Protein Binding on the Pharmacological Activity of Highly Bound Antibiotics (Antimicrobial Agents and Chemotherapy, 2008)

Importance of Relating Efficacy Measures to Unbound Drug Concentrations for Anti-Infective Agents (Clinical Microbiology Reviews, 2013)

Protein Binding: Do We Ever Learn? (Antimicrobial Agents and Chemotherapy, 2011)

Concentration-dependent plasma protein binding: Expect the unexpected (European Journal of Pharmaceutical Sciences, 2018)