Study On The Preparation Technology Of The Microbubble Contrast Agent With Perfluorocyclobutane

To compare with Computed Tomography and Nuclear Magnetic Resonance,Ultrasonic diagnosis has many advantages such as convenient, no radiation, cheap, real-time imaging and no damage, which is the most widely used diagnostic methods.However, ultrasonic imaging resolution is not enough now, which has limited the use of ultrasonic diagnosis in some areas.The gas in microbubbles has a strong ability to reflect ultrasound, so adding ultrasound contrast agents in the ultrasonic diagnosis can greatly improve the effect of ultrasound imaging resolution.About the research of ultrasound contrast agents before,mainly confined to the preparation of ultrasound contrast agents in different ways, and measure the size and concertration of microbubbles, at last,detecting the effect of the echo in vivo and in vitro in order to judge if the ultrasound contrast agents prepared can meet the demand of clinical application. Few scholars has a research on the influence of process variables on the microbubble properties. In this paper, we prepared PLLA and ST68 microbubble ultrasound contrast agents, and explore the influence of process variables on the microbubbles in depth, to involve changing the property of ultrasound contrast agents by alter the process parameters.We using double emulsion method to prepare the PLLA microbubble ultrasound contrast agents,The experiments also discuss the influence on microbubble concertration and gas covering amount about experimental process parameters such as emulsification rotate speed, the surfactant concentration,emulsification time and so on. The experimental results show that the concertration and covering amount of PLLA microbubbles will increase first and decrease later with the increasing of emulsification rotate speed, the surfactant concentration, emulsification time; The concertration of PLLA can enhance the concertration of microbubbles; the concertration of PVA can increase the concertration and the covering amount of the microbubbles; Adding isopropyl alcohol has little influence on the concertration and covering amount of the microbubbles. The average particle size of the microbubbles prepared is 3.04um. The concertration is 2.56×108/ml, covering amount is 99.2ul/ml. The microbubbles’surface are smooth, slightly fold,they have uniform particle size distribution and the range is narrow. The microbubbles can be prepared to be dry powder and can be saved easily. We using Ultrasonic cavitation method to prepare the ST68 microbubble ultrasound contrast agents. Experiments also discuss the influence on particle size, microbubble concertration and gas covering amount about experimental process parameters such as Ultrasonic time, the ultrasonic power, sodium chloride concentration and so on.The experimental results show that the concertration and covering amount of ST68 microbubbles will increase first and decrease later with the increasing of ultrasonic power and time.However, the average size of microbubbles has little variation with the changing ultrasonic power and time. But, through changing the ultrasonic power and time, we can alter the size of the microbubbles in a certain range. The average particle size of the microbubbles prepared is 1.64um. The concertration is 6.91×108/ml,covering amount is 254.7ul/ml. Compare with PLLA microbubbles, the ST68 microbubbles have smaller size and more uniform, but it can’t be made to dry powder. So in this paper, we try to preserve microbubbles at low temperature, at the same time, put sodium chloride in the solution to reduce the freezing point in order to make the microbubbles can be preserved at low temperature easily and improve the stability of microbubbles.