Patent ID: 7588751

Claim:
A method of preparing a radiographic contrast medium comprising a liposome, the method comprising the steps of: (a) combining at least one phospholipid selected from the group consisting of phosphatidylcholine, phosphatidylserine, phosphatidylinositol, phosphatidylglycerol, phosphatidylethanolamine, sphingomyelin, phosphatidic acid, dipalmitoylphosphatidylcholine, distearoylphosphatidylcholine, dimyristoylphosphatidylcholine, dioleylphosphatidylcholine, dipalmitoylphosphatidylglycerol, distearoylphosphatidylserine, distearoylphosphatidylglycerol, dipalmotoylphosphatidylinositol, distearoylphosphatidylinositol, dipalmitoylphosphatidic acid, distearoylphosphatidic acid, 1,2-dioleoyloxy-3-(trimethylammonium)propane, N,N-dioctadecylamidoglycylspermine, dimethyloctadecylammonium bromide, N-[1-(2,3-dioleyloxy)propyl]-N,N,N-trimethylammonium chloride, 2,3-dioleyloxy-N-[2(spermine-carboxamido)ethyl]-N,N-dimethyl-1-propaneaminiumtrifluoroacetate and N-[1-(2,3-dimyristyloxy)propyl]-N,N-dimethyl-N-(2-hydroxyethyl)ammonium bromide, a sterol and a lipid containing a polyalkyleneoxide group with liquid carbon dioxide in a pressure vessel and then increasing a pressure within the pressure vessel to form a super critical carbon dioxide, (b) adding thereto an aqueous solution containing at least one iodine compound selected from the group consisting of iomeprol, iopamidol, iohexol, iopentol, iopromide, ioxilane, iosimide, iobenzol, iotrolan, iodixanol, iodecimol, iotasl, metrizamide, 1,3-bis-[N-3,5-bis-(2,3-dihydroxypropylaminocarbonyl)-2,4,6-triiodophenyl]-N-hydroxyacetyl-amio]-propane, diatrizoic acid, sodium diatrizoate, meglumine diatrizoate, acetorizoic acid, diprotrizo acid, iodamide, sodium iodipamide, meglumine iodipamide, iodohippuric acid, iodomethamic acid, iodopyracet, iodo-2-pyrridone-N-acetic acid, 3,5-diiodo-4-pyridone-N-acetic acid, iothalamic acid, metrizoic acid, iopanoic acid, iocetamic acid, iophenoic acid, sodium thyropanoate and sodium iopodate to form micelles and (c) discharging the carbon dioxide to form liposomal vesicles enclosing the iodine compound.