The Role of Unbound Drug in Pharmacokinetics/Pharmacodynamics and in Therapy

Author(s): Rosario Calvo, John C. Lukas, Monica Rodriguez, Nerea Leal, Elena Suarez

Journal Name: Current Pharmaceutical Design

Volume 12 , Issue 8 , 2006

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Abstract:

The evolution of research on drug protein binding is discussed with the unbound concentration (Cu) and the unbound fraction (fu) as protagonists. Particular attention is paid to the mechanisms via which alterations in binding affect the pharmacokinetics (PK) and the effect, or independently the pharmacodynamics (PD). Apart from albumin, the important α-acid glycoprotein (AGP), as well as specific drug classes and applications in the clinic and development (routine monitoring, cancer and HIV therapy, allometry) are addressed. The flaws with the classical method of indirectly calculating the Cu or the unbound PK/PD parameters, based on the fu in vitro, are related to the intrinsic complexity and variability in the outcomes. Increased focus is urged on directly estimating the unbound PK/PD and also on using population statistical methods.

Keywords: Unbound drug, protein binding, AGP variability, PK/PD

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Article Details

VOLUME: 12
ISSUE: 8
Year: 2006
Page: [977 - 987]
Pages: 11
DOI: 10.2174/138161206776055967
Price: $65

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