Potential error in the measurement of tissue to blood distribution coefficients in physiological pharmacokinetic modeling. Residual tissue blood. II. Distribution of phencyclidine in the rat.

A model for predicting the magnitude of error (% Err) in measuring tissue concentrations of a compound that have not been corrected for residual blood in the tissue was previously developed. The model was tested using data for phencyclidine tissue distribution in the rat. It is shown that % Err may be expressed as a function of volume fraction of blood in tissue (VF)B and tissue-to-blood distribution coefficient. Correction for residual blood is important when the volume fraction of the blood in the tissue is large and when the compound is not taken up substantially by the tissue. On the other hand, a correction may not be necessary when (VF)B is small and uptake of the compound into the tissue is substantial.