Heavy silicone oils

Fluorinated Molecules in Eye Surgery Experimental and Clinical Benefit of a Heavy Silicone Oil Oxane Hd (Mixture of Silicone Oil and RMN3 Fluorine Olefin) in the Treatment of Retinal Detachment... 

In this content, we developed and studied a solution of a fluorine-containing compound, RMN3, and silicone oil. This so-called heavy silicone oil has been on the market since May 2003 under the name of Oxane Hd . 

The formulation of silicone oil and RMN3 is therefore a solution of a fluorine-containing compound, RMN3, and of a 5700-cSt silicone oil. It is the result of cooperation between the IMRCP laboratory of the Paul Sabatier University in Toulouse (Dr. Rico-Lattes), the Ophthalmology Department team of the Rangueil Teaching Hospital of Toulouse (Professor Mathis) and Chauvin Baush Lomb Laboratories and Opsia companies (Toulouse). This heavy silicone oil has been marketed since May 2003 by Chauvin Baush Lomb Laboratories. The characteristics of Oxane Hd are summarised in Table 2. 

Fig. 4. Experimental study of RMN3-silicone oil mixture in rabbits (electron microscopy after 1-month internal tamponade with heavy silicone oil) (a) moderate intercellular oedema between photoreceptor external articles note the presence of a mundane vesicle (b) normal aspect of retina internal layers and (c) normal aspect of internal limiting layer and vitreous cavity.

In our series, full retinal reapplication was achieved in 16 of 17 patients (95%). There was only one case of major emulsification immediately after surgery. This was consistent with Wolfs results [47], who reported no case of emulsification with Oxane Hd . Only once did we note silicone passage into the anterior chamber. Wolf reported the post-operative passage of heavy silicone oil (1.03 g/cm ) into the anterior chamber in two aphatic patients despite superior peripheral iridectomy. The incidence of post-operative glaucoma was lower in our series than that reported by Wolf [47] and other publications on standard silicone oil complications [16,17]. Heavy oil removal was uneventful in all patients in Wolfs series, who used 1.03 g/cm density silicone oil. Likewise, in all our patients operated on with the same density (1.03 g/cm ) heavy silicone oil (17 eyes), active extraction with the extraction module of the vitrectomy apparatus posed no problem. 

On the basis of the results, it appears that heavy silicone oil Oxane Hd , the first formulation of this type on the market, as a temporary internal tamponade is equally tolerated as standard silicone oil in the surgical treatment of complex retinal detachment. It does not pose any emulsification or major fragmentation problem, as encountered with other heavier than water products. Its effectiveness on inferior and posterior dehiscence tamponade appears to be very effective to currently available anatomical results. Oxane Hd , moreover, presents in this context a real benefit in the treatment of complex retinal detachment [48]. Retinopexy quality and the absence of residual subretinal fluid in internal tamponade of inferior lesions, extensive inferior retinectomies in particular, may reduce the risk of recurrence of complex retinal detachment by PVR. More extensive studies are now in course to see the limits of Oxane Hd in comparison with new analogues such as Densiron 68 , which has been marketed recently. 

S. Wolf, V. Schdn, P. Meier, P. Wiedemann, Silicone oil-RMN3 mixture ( heavy silicone oil ) as internal tamponade for complicated retinal detachment, Retina 23 (2003) 335-342. 

V. Pagot-Mathis, X. Benouaich, A. Mathis, I. Rico-Lattes, A. Dumoulin, Management of complicated retinal detachment using a heavy silicon oil as temporary tamponade, J. Fr. Ophthalmol. 29 (2006) 137-145. 

Intensive investigations have shown that specific silica-silicone mixtures or paraffin oil systems are considerably more universal in their applicability and that their effectiveness is independent of both water hardness and the nature of the surfactant-builder system employed [31-33]. Therefore, most heavy-duty detergents in Europe have silicone oil and/or paraffins as foam depressors. Soap has almost lost its importance as a foam regulator. Silica-silicone systems, frequently called silicone antifoams, are usually commercially available as concentrated powders. The key silicone oils used for antifoams are dimethylpolysiloxanes. 

More recently, other heavier than water products have been developed for temporary internal tamponade. These are fluorosilicones [46,47], semifluorinated alkanes [1,7], heavy fluorocarbon liquid (HFCL) oligomers [5,7] and solutions of fluorine-containing compound and silicone oil [8-10,47],... 

It is noteworthy that this formulation is different from fluorosilicones. Fluorosili-cones are fluorine-containing silicone oils with a 1.35 g/cm density. Their poor tolerance in animals and men was demonstrated by experimental studies [45,46] ocular hypertonia, keratopathy, early emulsification and severe inflammatory reactions. They cannot therefore be used as a heavy internal tamponade product. 

Physical characteristics Standard silicone oil HFCL HFCL oligomers Heavy oil (Oxane 5700- RMN3 formulation)... 

After a 40-month mean follow-up period (range 3-66 months after removal of the heavy oil), total retinal reapplication was achieved in 16 cases. Three patients suffered from RD recurrence under silicone oil by proliferative vitreretinopathy (PVR) and one after silicone oil removal. Post-operative visual acuity, better than quantitative vision, making deambulation possible, was achieved in 10 patients with a mean acuity of 1/20 and at least 3/10 in 3 patients. 

Although the methyl silicone oils are soluble in benzene and in the lighter hydrocarbons, they are only partially soluble in alcohol and in the heavy hydrocarbons. The relative insolubility in petroleum lubricating oil may be the reason for the success of silicone oils in suppressing foam in certain engine oils at the limit of solubility the silicone may set up a high local concentration at the oil-air interface and so exercise a surface-active effect. Whatever the mechanism, a very... 

Using a 4-in. test tube half filled with silicone oil and a stirrer made from heavy wire, melting points can be determined on an electric heater filled with sand (Fig. 4, p. 49). Once the sand is warmed up it has a very large temperature gradient from top to bottom, so the temperature and heating rate can be adjusted according to the depth of the test tube in the sand. 

Analysis. Heavy Products. High molecular weight hydrocarbons were analyzed by gas-liquid chromatography. A known volume of undecane was added to the irradiated sample as internal standard. The stationary phase was silicone oil on Chromosorb W. The column was 1.50 meters long its diameter was 3 mm. A flame ionization detector was used. 

Uses Emulsifier, detergent, wetting agent, dispersant, solubilizer, coupling agent for cosmetics, l l cleaners, paints, textiles, paper processing, adhesives, metalworking emulsifier for heavy petrol, oils and silicone fluids... 

An adhering deposit may be made more freely running and removed more easily if ammonia is introduced into a fuel-oil boiler [462]. Particularly serious complications arise in the burning of fuel oil in gas turbines, when the ash sticks to the vanes of the turbine. By adding substances containing silicon, aluminum, magnesium, and zinc compounds to the heavy fuel oils used for this purpose, the melting point of the ash is considerably raised and its tackiness is thereby reduced. It is also recommended in [463] that up to 0.15% kaolin powder should be added to the fuel oil this ensures the formation of loose, easily removed deposits and reduces the adhesion of particles to the turbine vanes by a factor of several times. 

Silicone oil (vacuum technology) A heavy, low vapor pressure, silicone-based (rather than... 

This chapter deals with the noncatalytic hydrodesulfurization (NHDS), hydrodemet-allization (NHDM), and hydrocracking (NHDC) of heavy crude oil and atmospheric residue. Some experiments were carried out in two different bench-scale units equipped with fixed-bed reactors in series operated in adiabatic and isothermal modes. The reactors were loaded with inert material (silicon carbide). Different feedstocks were used for the tests 13°API heavy crude oil, 21°API crude oil, atmospheric residue from the 13°API heavy crude oil, and atmospheric residue from the 21°API crude oil. The effects of pressure, residence time, temperature, and type of feed on noncatalytic reactions and axial reactor temperature profiles are examined. Reaction kinetics of the different noncatalytic reactions is studied by following the power-law approach. 

Oil drops of 2-5 /iL were introduced into 0.4 cm i.d. capillary tubes containing the aqueous phase. The more viscous heavy oils were heated for a short period to facilitate this addition. The tubes were then sealed with a tightly fitting silicon-rubber septum. A teflon screw was used to apply pressure on the septum after the capillary tube was inserted into the shaft of the tensiometer. In this manner, temperatures up to 200°C were achieved without loss of liquid. 

---