A new, heavier-than-water silicone oil: A solution of perfluorohexyloctane in polydimethylsiloxane.

PURPOSE To pre p a re and explore new solutions of semifluorinated alkane in silicone oil, which have a specific gravity slightly higher than silicone oil and vitreous fluid (referred to in the following as heavier-than-water silicone oils (HWSs), and to investigate, in vitro, whether HWSs can be used to plug retina holes, while allowing dehydration of the subretinal space. METHODS HWS solutions were pre p a red with silicone oil 5000 and perfluorohexyloctane (F6H8). The stabiliy was investigated under different conditions. The viscosity was determined by means of a capillary viscometer. The surface and interface tension were measured using the ring method. RESULTS HWSs are insoluble in an aqueous medium. Densiron68 (HWS 1.06) is a transparent homogeneous liquid which is slightly heavier (1.06 g/cm3) than water and has a refractive index close to that of vitreous liquid. Densiron68 (HWS 1.06) has a low viscosity (1480 mPas) and interface tension (40.82 mN/m), making it an effective tamponade in the surgical treatment of an inferior detached retina. In addition, the interfaces between Densiron68 and other perfluorocarbon liquids are clearly visible. However, the interface layer between Densiron68 and water is not clear. Finally, all HWSs are stable over the long term at ambient temperatures, as well as physically and thermally resistant. CONCLUSIONS Due to its physiochemical properties, Densiron68 could meet the requirements for a heavier-than-water tamponade. (Eur J Ophthalmol 2005; 15: 627-37).