Contrast agents

Abstract

Contrast agents comprising microbubble-generating carbohydrate microparticles having a surfactant admixed within the microparticulate structure, with the proviso that the surfactant is not a C 10-20 fatty acid, are disclosed. Processes for preparing contrast agents also are disclosed.

1 - 13 . (canceled)  
     
     
         14 . The method of generating an enhanced echocardiographic image of a human or non-human body comprising: administering into the pulmonary system of said body an echocardiographic contrast enhancing amount of a contrast agent comprising gasmicrobubble-generating aggregates of microparticles; applying to a part of said body ultrasound at a frequency of 0.1 to 15 MHZ; and generating said image; said microparticles comprising a water soluble matrix material and a surfactant, the microbubbles generated by said aggregates comprising SF 6  or a fluorinated low molecular weight hydrocarbon, said aggregates being 20-125 Φm in size and said microparticles having an average size of 0.1 to 50 Φm.  
     
     
         15 . The method as claimed in  claim 14  in which the surfactant is selected from the group consisting of straight chain aliphatic carboxylic acids and salts, sorbitan esters and mono- and di-glycerides thereof; aralkanoic acids and the salts thereof; steroid acids; sterols; straight chain aliphatic alcohols; phospholipids; alkali metal alkyl sulphates and sulphonated esters; polyoxyethylene-polyoxypropylene copolymers; polyoxyethylated sorbitan esters; and mixtures of any of the foregoing.  
     
     
         16 . The method as claimed in  claim 14  in which the surfactant comprises a lipophilically modified carbohydrate.  
     
     
         17 . The method as claimed in  claim 14  in which the surfactant is present in an amount of 0.1-2.0% w/w relative to the water soluble matrix.  
     
     
         18 . The method as claimed in  claim 14  for which the microbubbles generated by said aggregates contain air in admixture with said SF 6  or fluorinated hydrocarbon.  
     
     
         19 . The method as claimed in  claim 14  for which the microbubbles generated by said aggregates comprise carbon tetrafluoride.  
     
     
         20 . The method as claimed in  claim 14  in which the water soluble matrix is a carbohydrate.  
     
     
         21 . The method as claimed in  claim 20  in which the carbohydrate is a polysaccharide.  
     
     
         22 . The method as claimed in  claim 20  in which the carbohydrate is a sugar alcohol.  
     
     
         23 . The method as claimed in  claim 14  which is non-contrast giving before use, but which becomes effective on administration.  
     
     
         24 . The method as claimed in  claim 15  which is non-contrast giving before use, but which becomes effective on administration.  
     
     
         25 . The method as claimed in  claim 16  which is non-contrast giving before use, but which becomes effective on administration.  
     
     
         26 . The method as claimed in  claim 17  which is non-contrast giving before use, but which becomes effective on administration.  
     
     
         27 . The method as claimed in  claim 18  which is non-contrast giving before use, but which becomes effective on administration.  
     
     
         28 . The method as claimed in  claim 19  which is non-contrast giving before use, but which becomes effective on administration.