(PERFLUOROALKYL)-ETHENE AND 1,2-BIS(PERFLUOROALKYL)-IODO-ETHENE AND POLYBROMO-ETHENE - SYNTHESIS AND PRELIMINARY EVALUATION AS CONTRAST AGENTS FOR DIAGNOSIS

Five series of F-alkyl- and 1,2-bis(F-alkyl)ethene derivatives [1], wi th one iodine or several bromine atoms on the double bond, have been s ynthesized and their radiopacity and biological tolerance evaluated. T hese compounds display excellent opacity to X-rays but their biocompat ibility was usually insufficient to warrant further evaluation as inje ctable constrast agents. One series, however, 1,2-bis(F-alkyl)-1-iodoe thenes, CnF2n+1CH=CICn'F2n'+1 (Fnn'IE), with (n+n) greater than or equ al to 8, appeared to reach the initial objectives : their radiopacity is about 4 times higher than that of perfluorooctyl bromide (PFOB, who se emulsions are presently undergoing clinical evaluation). They are s ufficiently inert and their biological tolerance is superior to 50 g/k g body weight when given intraperitoneally in mice. Preliminary emulsi fication tests are also promising : a 50% w/v F46IE emulsion could be produced whose average particle size was only 0.28 mu m after 3 months at 25 degrees C, without change from the 15th day onwards.