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ABSTRACT: Purpose
Volume of distribution is an important pharmacokinetic parameter in the distribution and half-life of a drug. Protein binding and lipid partitioning together determine drug distribution.Methods
Here we present a simple relationship that estimates the volume of distribution with the fraction of drug unbound in both plasma and microsomes. Model equations are based upon a two-compartment system and the experimental fractions unbound in plasma and microsomes represent binding to plasma proteins and cellular lipids, respectively.Results
The protein and lipid binding components were parameterized using a dataset containing human in vitro and in vivo parameters for 63 drugs. The resulting equation explains ~84% of the variance in the log of the volume of distribution with an average fold-error of 1.6, with 3 outliers.Conclusions
These results suggest that Vss can be predicted for most drugs from plasma protein binding and microsomal partitioning.
SUBMITTER: Korzekwa K
PROVIDER: S-EPMC5285473 | biostudies-literature | 2017 Mar
REPOSITORIES: biostudies-literature
Pharmaceutical research 20161213 3
<h4>Purpose</h4>Volume of distribution is an important pharmacokinetic parameter in the distribution and half-life of a drug. Protein binding and lipid partitioning together determine drug distribution.<h4>Methods</h4>Here we present a simple relationship that estimates the volume of distribution with the fraction of drug unbound in both plasma and microsomes. Model equations are based upon a two-compartment system and the experimental fractions unbound in plasma and microsomes represent binding ...[more]