The difference between Vd and V<sub>ss</sub>

The difference between Vd and Vss

There are many terms used to represent volume of distribution, but two common ones are Vd and Vss. Vd is the apparent volume of distribution. It can be calculated using the following equation:

 Vd=\frac{F*D}{AUC_{0-t}*k_{el}}

Vss is the apparent volume of distribution at steady state. Or, the sum of all volume terms in a multicompartment model. It can be calculated using the following equation:

 Vss=\frac{D*AUMC_{infty}}{AUC_{infty}^2}

Today’s pharmacokineticists and PK/PD modelers are under more pressure than ever to quickly and accurately characterize the safety and efficacy profiles of investigational drugs. They need the right tools to perform non-compartmental analysis (NCA), build pharmacometric models, and generate reports that communicate their findings.

Phoenix 7.0’s new features and enhancements are the direct result of user feedback we received to make the world’s most advanced PK/PD software package even better.

Watch this webinar to learn how Phoenix 7.0 helps you handle bigger datasets, perform lightning-fast NCA, and make gorgeous plots.

Nathan Teuscher

About the Author

Nathan Teuscher

More Posts by This Author

Dr. Nathan Teuscher is the Vice President of Pharmacometric Solutions at Certara. He is an expert in clinical pharmacology, pharmacometrics, pharmacokinetics and pharmacodynamics and was trained by David Smith at the University of Michigan. Dr. Teuscher has held leadership positions in biotechnology, pharmaceutical and contract research companies. In 2008 he established the Learn PKPD.com website to share his knowledge with the community. Prior to coming to Certara, he was the Founder and President of PK/PD Associates.