Rate of Drug Distribution

In many cases, groups of tissues with similar perfusion-partition ratios all equilibrate at essentially the same rate such that only one apparent phase of distribution is seen (rapid initial fall of concentration of intravenously injected drug, as in Figure 1-3B). It is as though the drug starts in a "central " volume (Figure 1-1), which consists of plasma and tissue reservoirs that are in rapid equilibrium with it, and distributes to a "final" volume, at which point concentrations in plasma decrease in a log-linear fashion with a rate constant of k (Figure 1-3B).

The volume of distribution at steady state (Vgg) represents the volume in which a drug would appear to be distributed during steady state if the drug existed throughout that volume at the same concentration as that in the measured fluid (plasma or blood). V,s also may be appreciated as shown in Equation (1-8), where Vc is the volume of distribution of drug in the central compartment and Vt is the volume term for drug in the tissue compartment:

Was this article helpful?

0 0
Diabetes 2

Diabetes 2

Diabetes is a disease that affects the way your body uses food. Normally, your body converts sugars, starches and other foods into a form of sugar called glucose. Your body uses glucose for fuel. The cells receive the glucose through the bloodstream. They then use insulin a hormone made by the pancreas to absorb the glucose, convert it into energy, and either use it or store it for later use. Learn more...

Get My Free Ebook

Post a comment