In vivo kinetics of microbubbles of SHU 508 A (Levovist((R))): Comparison with Indocyanine Green in rabbits

The aim of this study was to evaluate in vivo, kinetics of microbubbles of SH U 508 A, in comparison with Indocyanine Green, a dye used as an indicato r of blood flow. Microbubble kinetics were evaluated in various vessels (i. e., vena cava, aorta, renal artery, renal vein and portal vein) in rabbits after injection of SH U 508 A by measuring Doppler signals (n = 5), The kin etics of Indocyanine Green were evaluated by measuring absorbance using a p hotodiode (n = 5), Test substances (SH U 508 A 300 mg/mL and Indocyanine Gr een 1.25 mg/mL) were injected IV at a dose of 0.1 mL/kg B.W. Peak signal in tensity was observed immediately after injection of SH U 508 A, followed by biphasic decay, The rates of biphasic decay were similar in all vessels. A second peak of the signal, which indicated recirculation of the microbubbl es, was observed in the vena cava, The circulation and recirculation times of the microbubbles after injection of SH U SOS A were similar to that of I ndocyanine Green. These findings suggest that the majority of SH U 508 A mi crobubbles circulate through the body similarly to blood flow, without rete ntion, in the vasculature. (C) 1999 World Federation for Ultrasound in Medi cine & Biology.