On the Origin of the Apparent Volume of Distribution and Its Significance in Pharmacokinetics

The apparent volume of distribution was defined for the first time as phase that can hold total amount a substance at measured concentration, in system composed two immiscible media are contact under conditions constant volumes, equilibrium. Its value is not affected by solute mass and it only depends on volume, volumes affinity phases system. Using this new concept distribution, we were able to demonstrate certain compartment multi-compartment multi-phasic pharmacokinetic models represent actual physiological body fluids accessible drugs. classical now fully explained be used provide accurate estimation parameters hydrophilic In contrast, absence tissue-plasma partition coefficients, lipophilic drugs do follow one-compartment model unlikely adequately described with models.