StudyonthePreparation Of Octafluoropropane-containing Albumin Microbubbles And Whole Blood Elimination Kinetics Of Octafluoropropane In Anesthetized Canines After Intravenous Administration Of The Albumin Microbubbles, A New Ultrasound Contrast Agent

Ultrasound contrast agents is a kind of diagnostic agent that have the potential to enhance significantly the yield of Doppler-ultrasound examination and thus allow better imaging. Compared with other imaging techniques such as CT or MRI, contrast echography is a far better diagnostic technique which has evolved into a reliable and simple beside technique for the assessment of organ and tissue function, using the information obtained post -perfusion. In echography, image quality relies on the intensity of echo signals. Gas bubbles are outstanding scatters of ultrasound, and it become clear that they could be the ideal components of an ultrasound contrast agent. By the late 1960s, many research groups have been studying on preparing microbubble suspensions in a attempt to improve the technology of forming and stabilizing bubbles. The use of bubbles has been excitingly proposed, and the research work is valuable in our country.This study was undertaken to evaluate the value of dextrose for enhancing the stability of perfluoropropane-filled albumin microbubble, as well as evaluating the effect of lyophilization under continuous negative pressure on microbubble size distribution. Six different albumin solution with increasing dextrose concentration were sonicated in controlled power and frequency to prepare microbubbles. Stability of the albumin microbubble was investigated when adding dextrose. The preparation containing 10% dextrose concentration was also subjected to lyophilization under continuous negative pressure. Microbubble size distribution was measured with a Coulter-3-Multisizer II (Beckman Coulter, Inc). finally, the elimination kinetics of the octafluoropropane component were studied in anesthetized canine models. Three different dosages of 0.3, 0.6, and 0.9ml/kg was administered intravenously.Results of heat resistance of the albumin microbubbles showed that dextrose can enhance the stability of microbubble. On Coulter counter studies, lyophilized microbubbles have a smaller size distribution with 99.24% + 0.18% of microbubbles <10um in diameter and 94.77%+0.87% <5um in diameter(P<0.05, compared with non-lyophilized microbubble suspensions). Finally, statistic moment analysis showed rapid octafluoropropane elimination with mean residence times of 67,63,and 64 seconds for the three dosages.