Free fraction

The free fraction is a parameter in pharmacokinetics and receptor-ligand kinetics. One speaks of two different free fractions:

• Plasma free fraction, previously referred to as ƒ₁,[1] is now referred to as ƒ_P according to consensus nomenclature.[2]
• Tissue free fraction (ƒ_ND), previously referred to as ƒ₂[1]

The plasma free fraction is the fraction of the ligand at equilibrium in blood plasma that is not bound to plasma proteins.

See also

• Binding potential

References

1. Roger N. Gunn; Steve R. Gunn; Federico E. Turkheimer; Vincent J. Cunningham (2002). "Positron Emission Tomography Compartmental Models: A Basis Pursuit Strategy for Kinetic Modeling". J. Cereb. Blood Metab. 22 (4): 1425–1439. doi:10.1097/00004647-200212000-00003. PMID 12468888.Table
2. Innis, R.B.; Cunningham, VJ; Delforge, J; Fujita, M; Gjedde, A; Gunn, RN; Holden, J; Houle, S; et al. (2007). "Consensus nomenclature for in vivo imaging of reversibly binding radioligands". J Cereb Blood Flow Metab. 27 (9): 1533–1539. doi:10.1038/sj.jcbfm.9600493. PMID 17519979.

Others

• Milak MS, Severance AJ, Ogden RT, Prabhakaran J, Kumar JS, Majo VJ, Mann JJ, Parsey RV (2008). "Modeling Considerations for 11C-CUMI-101, an Agonist Radiotracer for Imaging Serotonin 1A Receptor In Vivo with PET". J. Nucl. Med. 49 (4): 587–596. doi:10.2967/jnumed.107.046540. PMC 3580231. PMID 18344443.