PHARMACOLOGICAL COMPARTMENT VISCOSITY AND POLARITY MEASURED WITH VERYLOW-FREQUENCY EPR IN TUMORS OF LIVING ANIMALS

Quantitative measurements of the viscosity of a non-vascular pharmacol ogical compartment in a living animal are presented, Using novel, very low-frequency electron paramagnetic resonance spectroscopy, capable o f measurements in humans, novel analytical techniques and partially de uterated spin probes, the viscosity of the body water of murine fibros arcomas implanted in the leg of a living animal were measured, The ave rage viscosity was 1.9 +/- 0.2 cP. Variation of the viscosity with tum or size and histology did not appear to be significant.