Heribert Miklautz

PHYSICOCHEMICAL PARAMETERS OF X-RAY CONTRAST MEDIA

RATIONALE AND OBJECTIVESOsmolality, including “dynamic osmolality,” which is observed during dilution in the plasma, viscosity, density, and partition coefficient of 11 commercially available contrast media and two new nonionic monomers were determined. METHODSOsmolality was measured by vapor pressure osmometry, viscosity by determining flow in microcapillaries, and partition coefficient in n-octanol or n-butanol/water mixtures by inductively coupled plasma mass spectroscopy or x-ray fluorescence analysis of iodine concentrations. RESULTSFor the commercially available contrast media, the following statistically significant ranking of osmolality was obtained at 300 mg iodine/mL: iotrolan ± ioxaglate < iopromide < iopamidol < ioversol = iohexol < iopentol ± meglumine diatrizoate. The novel nonionic monomers, ZK 119095 and ZK 139129, had very low osmolalities, and ZK 139129 was isotonic to blood. The partition coefficient for the system n-octanol/water was lowest for the ionic compounds ioxaglate and diatrizoate followed by the nonionic dimer iotrolan. In n-butanol, iotrolan showed the lowest partition coefficient. CONCLUSIONS“Dynamic osmolalities” of contrast media may differ from static values possibly because of the formation of “quasi-oligomers.” Especially for ZK 139129, disaggregation occurred during dilution and the osmolality increased slightly. However, osmolality was lower than for any other monomer during the whole dilution process.

Über das Assoziationsverhalten von Methylglukaminsalzen der Dicarbonsäure‐bis‐(3‐carboxy‐2,4,6‐trijod‐anilide) in wäßrigen Lösungen

Messungen der Aktivierungsenergien des viskosen Flusses von Methylglukaminsalzlösungen einer homologen Reihe der Dicarbonsäure‐bis‐(3‐carboxy‐2,4,6‐trijod‐anilide) haben ergeben, daß der Ordnungsgrad solcher Lösungen stark von der Länge der Dicarbonsäure abhängt. Diese Abhängigkeit durchläuft beim Glutarsäurehomologen ein Maximum, was sich durch eine entgegengesetzte Überlagerung von intermolekularer und hydrophober Assoziation erklären läßt.