Studies of in vivo electropermeabilization by gamma camera measurements ofTc-99m-DTPA

A protocol was developed to study the drug uptake from in vivo electroperme abilization at different settings of parameters influencing the uptake effi ciency. Radiolabelled diethylenetriaminepentaacetic acid (DTPA) was used to trace the distribution and internalization of a hydrophilic drug after in vivo electropermeabilization. Skeletal muscle tissue in rat was treated wit h permeabilizing: electric pulses before or after intravenous administratio n of Tc-99m-DTPA. The drug accumulation in the treated volume was subsequen tly evaluated with a scintillation camera. The dependence of uptake on fiel d strength and duration of the applied electric pulses was investigated for exponentially decaying pulses and square wave pulses. Further, the uptake dependence on time interval between injection and pulsation was studied as well as the uptake dependence on the number of pulses applied in a single e lectropermeabilization treatment. Dynamic gamma camera studies were perform ed to quantify the time scale of the drug uptake in electropermeabilized ti ssue. (C) 1999 Elsevier Science B.V. All rights reserved.