Stable microbubble suspensions as enhancement agents for ultrasound echography
AssigneeBracco International B.V.
InventorsMichel Schneider, Jean Brochot, Jerome Puginier, Feng Yan
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Abstract
Disclosed are injectable suspensions of gas filled microbubbles in an aqueous carrier liquid usable as contrast agents in ultrasonic echography. The suspensions comprise amphipathic compounds of which at least one may be a laminarized phospholipid as a stabiliser of the microbubbles against collapse with time and pressure. The concentration of phospholipids in the carrier liquid is below 0.01% wt but is at least equal to or above that at which phospholipid molecules are present solely at the gas microbubble-liquid interface. Also disclosed is a method of preparation of the stable suspensions of air or gas filled microbubbles.
Claims12
A method of making a suspension of air or gas filled microbubbles, said method comprising the steps of:
- selecting at least one film forming surfactant;
- converting said surfactant into a powder;
- contacting said powder with air or another gas;
- admixing said powder surfactant with an aqueous liquid carrier to form a suspension of air or gas filled microbubbles;
- introducing said suspension into a container;
- forming a layer of said microbubbles in an upper part of said container;
- separating said layer of microbubbles;
- and
- washing said separated microbubbles with an aqueous solution saturated with the microbubble gas.
A method of making an injectable suspension of gas-filled microbubbles in an aqueous carrier liquid, said method comprising the steps off
- suspending laminarized phospholipids in an aqueous carrier liquid, said phospholipids having been in contact with said gas prior to or after suspending, under conditions such that a concentration of microbubbles is sufficient to provide an echographic response is formed in said suspension;
- allowing a portion of said phospholipids to form a stabilization layer around said bubbles;
- and
- thereafter depleting the aqueous carrier liquid of excess phospholipids not involved in microbubbles stabilization.
Dependencies are inferred from the claim text.