Quantitative analysis of intratumoral infusion of color molecules

Intratumoral infusion has a potential for improving distribution of drugs. To optimize the infusion, we developed a novel technique to quantify the di stribution volume of color molecules (V-d) in solid tumors. Evans blue-labe led albumin was infused locally with the use of a needle into a rat fibrosa rcoma ex vivo under different pressures. After the infusion, tumor tissues were sectioned serially into thin slices. The blue area in each slice was q uantified with the use of the newly developed technique. The Vd was calcula ted based on the blue area and the slice thickness. Our data showed that in fusion pressure and volume (V-i) had significant effects on V-d. The median of V-d/V-i decreased from 2.99 to 1.79 when infusion pressure was increase d from 50 to 163 cmH(2)O, presumably due to retardation of convective trans port. In addition, the coefficient of variation in V-d/V-i was increased fr om 0.13 at 50 cmH(2)O to 0.64 at 163 cmH(2)O. The dependence of V-d/V-i and its variation on infusion pressure suggests that 1) infusion-induced tissu e deformation is unpredictable and 2) both the unpredictability and the int erstitial retardation of convective transport increase with infusion pressu re.