Physiochemical properties of a long-acting ultrasound contrast agent and in vivo parenchymal enhancement experiment

Objective To evaluate the physiochemical properties of a new lipid ultrasound contrast agent zhifuxian and its long acting enhancement effect on VX2 liver tumors. Methods The microbubbles size and distribution were detected under optical microscopy; the pH value and surface potential were assessed by the Zeta SIZER 3000; and the viscosity of contrast medium was measured by a viscosimeter. The in vivo contrast enhancement was performed on VX2 hepatic tumor models to find the long persistence of Zhifuxian's contrast enhancement. The rabbit livers were imaged by Sequoia 512 using second harmonic mode (3/6 MHz). The contrast images were analyzed by video intensity. Results The diameter of this new lipid microbubbles was found to distribute from 3 μm to 10μm, with 98% of the bubbles less than 8 μm. The bubbles concentration was 7×10 9/ml; the pH value was 6.42; and the electronic potential in saline was 35.5 mv. The liver contrast enhancement was initialized from 10 seconds and lasted for about 40 60 minutes. Conclusion Zhifuxian has been found to be biocompatible and no obvious noxious effect. It is capable to enhance parenchymal organ persistently for 40 60 minutes.