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At least 19 recordsLinked to original sources
PubMed1994

[Pharmacodynamic equivalence and clinical trial of a new fluorocarbon-free glycerol trinitrate pump spray with low ethanol content in comparison to a fluorocarbon-containing reference spray and a fluorocarbon-free pump spray with high ethanol content].

The pharmacodynamic equivalence of a fluorohydrocarbons-(FCH)-free glyceryl trinitrate (GTN, CAS 55-63-0)-containing pump spray with low ethanol content (Nitrolingual-Spray N; TL) versus a conventional FCH-containing GTN spray (Nitrolingual-Spray, R) as reference and a FCH-free GTN pump spray with high ethanol content (TH) was investigated by digital plethysmography (DPG) in a double-blinded, placebo-controlled (TL-matched placebo spray), randomized, period-balanced, 4-way cross-over design. Additionally the clinical tolerability (as perceived by the subjects and reported to the treatments-administrating investigator) was determined. The DPG-changes (cla; ratio of c-incisure and systolic a-wave) after the sublingual (s.l.) administration of 0.8 mg GTN of TL were biostatistically equivalent with R: the confidence intervals (CI) of the point estimates of the maximal decrease in cla (TL/R: 0.98, 90%-CI: 0.84 to 1.14) and the area-weighted average decrease in cla (TL/R: 0.97, 90%-CI: 0.80-1.16) were well in a 80-125% tolerance range. The time of occurrence of the maximal DPG-effect of TL was not different from R (distribution-free estimate of the difference TL-R: -2.25 min, 95%-CI: -9.5 min to 2 min). In contrast the maximal DPG-effect of TH after the s.l. administration of 0.8 mg GTN had a statistically significant earlier onset (TH-R: -6 min, 95%-CI: -9.5 min to -2 min) and a higher area-weighted average response (TH/R: 1.12, 90%-CI: 0.95 to 1.34). TH consistently caused an utterly unpleasant burning sensation in the mouth, thus this perceived local discomfort was distinctly different compared to all other treatments.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Sublingual↗
PubMed2002

Surface characterization and platelet adhesion studies of aliphatic polyurethanes grafted by fluorocarbon oligomers: effect of fluorocarbon chain length and carboxylic acid group.

The surfaces of aliphatic polyurethane films, which were synthesized by 1,6 hexamethylene diisocyanate, poly(tetramethylene glycol) and 1,4 butanediol, were modified by grafting different chain length of fluorocarbon oligomers. The fluorocarbon oligomers on polyurethane surfaces were terminated with trifluorocarbon or carboxylic acid functionality. The alkyl groups were also grafted onto polyurethane surfaces for comparison. The surface characterization and platelet-contacting property were studied using electron spectroscopy for chemical analysis (ESCA), static contact angle analysis and in vitro platelet adhesion experiments. The effects of fluorocarbon oligomers and their terminal functionalities are discussed. The ESCA results demonstrate the fluorocarbon enrichment at the outmost layer in fluorocarbon oligomer grafted polyurethanes. The fluorocarbon content at the surface increases with increasing the chain length of fluorocarbon oligomers. The fluorocarbon oligomer grafted polyurethanes exhibit highly hydrophobic surfaces, while alkyl groups grafted polyurethanes show relatively hydrophobic surfaces compared with the untreated polyurethane. The in vitro platelet adhesion experiments indicated that the fluorocarbon oligomer and carboxylic acid functionality significantly reduced the number and the degree of activation of the adherent platelets.

Journal Article↗
PubMed1975

Determination of fluorocarbon 11 and fluorocarbon 12 in post-mortem tissues: a case report.

This report describes the death of a teenager due to inhalation of fluorocarbon aerosol propellants and presents a method for the determination of trichlorofluoromethane (fluorocarbon 11) and dichlorodifluoromethane (fluorocarbon 12) in post-mortem samples. The post-mortem blood and tissue levels of these fluorocarbons are also presented. The distribution of fluorocarbon 11 and fluorocarbon 12 is similar to that observed in chloroform deaths.

Adolescent↗
PubMed1986

[Toward a second generation of fluorocarbon emulsions. Methodologies: synthesis of fluorocarbons, formulation, preparation and control of emulsions].

The fluorocarbons to be used as intravascular gas carriers may be prepared: by fluorination of hydrocarbons, by means of gaseous fluorine or of metallic fluorides or by electrolysis in anhydrous hydrogen fluoride; by selective synthesis from small fluorinated molecules. Selective synthesis seems preferable because of the high purity of the compounds thus obtained, allowing fairly simple purification and detoxification procedures. The adequacy of fluorocarbons for intravascular use (limited by the values of some of their crucial physicochemical properties such as vapour pressure, gas dissolving power, viscosity) was found dependent of their molecular weight range, preferably between 460 and 540 dalton. Ionic balance, osmolarity, viscosity, mean particle size and particle size distribution are among the most important criteria to be respected in the preparation of biocompatible emulsions. Several physicochemical methods were developed for selecting the best ingredients and the best emulsification procedures and for evaluating the stability of the emulsions to storage and to thermal stress. The combination of these physicochemical measurements may be used as a methodology for the optimisation and control of fluorocarbon emulsions as well as a way of evaluating new ingredients and formulations.

Biocompatible Materials↗
PubMed2004

Appearance of pure fluorocarbon micelles surveyed by fluorescence quenching of amphiphilic quinoline derivatives in fluorocarbon and hydrocarbon surfactant mixtures.

A halide-sensitive fluorescence probe was utilized to evaluate the miscibility of fluorocarbon and hydrocarbon surfactants in aqueous micellar systems. The fluorescence of 6-methoxy-N-1,1,2,2-tetrahydroheptadecafluorodecylquinolinium chloride, FC10MQ, was quenched by halide ions dissociated from the surfactant. The fluorescence in micellar solutions showed an initially rapid decay. This suggests that halide ions effectively quench FC10MQ fluorescence at the micellar surface. The subsequent slow decay corresponds to the quenching of FC10MQ fluorescence in the aqueous bulk phase by the free counterions. The Stern-Volmer plots for fluorescence quenching gave a distinct break at the critical micelle concentration of the cationic surfactants. The abrupt increase in fluorescence quenching is attributed to the solubilization of the probe in the micelles. The fluorescence quenching behavior provides direct information about the immiscibility of fluorocarbon and hydrocarbon species in micelles, and the results indicate that almost pure fluorocarbon micelles appear in surfactants mixtures.

Journal Article↗
PubMed1991

Fluorocarbon/lecithin emulsions: identification of EYP-coated fluorocarbon droplets and fluorocarbon-empty vesicles by freeze-fracture electron microscopy.

Freeze-fracture has been used to examine perfluorodecalin/egg yolk phospholipid emulsions (70:8, w/v%) destined to be used as injectable oxygen carriers. The fluorocarbon displays a specific granular aspect upon freeze-fracture which makes it readily recognizable and allows the distinction between two populations of objects on the micrographs: fluorocarbon droplets and water-filled lipid vesicles.

Egg Yolk↗
PubMed1994

Biodistribution of mixed fluorocarbon-hydrocarbon dowel molecules used as stabilizers of fluorocarbon emulsions: a quantitative study by fluorine nuclear magnetic resonance (NMR).

19F NMR spectroscopy was used to determine quantitatively the organ distribution and organ retention time in rats of the mixed fluorocarbon-hydrocarbon dowel molecule C6F13CH = CHC10H21 (F6H10E), which stabilizes highly concentrated injectable fluorocarbon emulsions destined for in vivo oxygen transport and delivery. The only fluorine resonances detected in the 19F NMR spectra of the organs analyzed were those of the F6H10E dowel itself, indicating that metabolites, if present, have very low concentrations (< 10(-4) M, limit of our assay). The F6H10E content in the liver peaked 1 day after administration (7 days for the spleen). At a dose of 3.6 g/kg body weight, the half-life of F6H10E in the liver was 25 +/- 5 days.

Animals↗
PubMedDate not supplied

[A new model describing the isolation of fluorocarbons from an organism: dissolution of fluorocarbons in the lipid components of blood].

Perfluorodecalin (PFD), intravenously administrated to rabbits in the form of submicron emulsion, quickly disappears from the blood stream and accumulates in the liver, spleen and bone marrow. The expiration rate of PFD from the body can be significantly enhanced by intravenous administration of sunflower oil emulsion. It is supposed that the limit stage of PFD excretion is a fluorocarbon transport from accumulatory organs to the lungs by lipid carriers (lipoproteins, chylomicrons and cell membranes) in which fluorocarbons are physically dissolved.

Animals↗
PubMed1996

Vesicles made of glycophospholipids with homogeneous (two fluorocarbon or two hydrocarbon) or heterogeneous (one fluorocarbon and one hydrocarbon) hydrophobic double chains.

The vesicle-forming ability of the new anionic double chain glycophospholipids 1-4, with either two hydrocarbon or two perfluorocarbon chains, or a mixed double chain (one fluorinated, one hydrogenated), was investigated. When dispersed in water, 1a-c,e, 2b,c and 4b,c readily gave heat-sterilizable vesicles, 30-70 nm in diameter. The galactose and mannose-based fluorinated vesicles were also highly stable on aging. The 6-substituted glucose derivatives 3 formed tubules that reversibly interconverted into vesicles, depending on temperature. The leakage rate in buffer of carboxyfluorescein or calcein from vesicles made from 1a-c,e 2b,c and 4b,c depended on the sugar (t1/2 galactose > mannose > glucose). It decreased significantly with increasing fluorination and length of the hydrophobic tails. The mixed perfluorocarbon/hydrocarbon-tailed amphiphiles were found to be miscible with both the two fluorocarbon chains and the two hydrocarbon chains derivatives. Such admixing tended, however, to increase the small unilamellar vesicles' permeability. In buffered serum, all the vesicles investigated were highly permeable, but incorporation of cholesterol or DSPC in vesicles made of 1e significantly reduced their permeability in serum. The new vesicle and membrane components have i.v. maximum tolerated doses as high as 500 mg/kg body weight in mice; hemolytic activity sharply decreases with increasing degree of fluorination.

Animals↗
PubMed2005

Prediction of conformational characteristics and micellar solution properties of fluorocarbon surfactants.

A molecular-thermodynamic theory is developed to model the micellization of fluorocarbon surfactants in aqueous solutions, by combining a molecular model that evaluates the free energy of micellization of fluorocarbon surfactant micelles with a previously developed thermodynamic framework describing the free energy of the micellar solution. In the molecular model of micellization developed, a single-chain mean-field theory is combined with an appropriate rotational isomeric state model of fluorocarbon chains to describe the packing of the fluorocarbon surfactant tails inside the micelle core. Utilizing this single-chain mean-field theory, the packing free energies of fluorocarbon surfactants are evaluated and compared with those of their hydrocarbon analogues. We find that the greater rigidity of the fluorocarbon chain promotes its packing in micellar aggregates of low curvatures, such as bilayers. In addition, the mean-field approach is utilized to predict the average conformational characteristics (specifically, the bond order parameters) of fluorocarbon and hydrocarbon surfactant tails within the micelle core, and the predictions are found to agree well with the available experimental results. The electrostatic effects in fluorocarbon ionic surfactant micelles are modeled by allowing for counterion binding onto the charged micelle surface, which accounts explicitly for the effect of the counterion type on the micellar solution properties. In addition, a theoretical formulation is developed to evaluate the free energy of micellization and the size distribution of finite disklike micelles, which often form in the case of fluorocarbon surfactants. We find that, compared to their hydrocarbon analogues, fluorocarbon surfactants exhibit a greater tendency to form cylindrical or disklike micelles, as a result of their larger molecular volume as well as due to the greater conformational rigidity of the fluorocarbon tails. The molecular-thermodynamic theory developed is then applied to several ionic fluorocarbon surfactant-electrolyte systems, including perfluoroalkanoates and perfluorosulfonates with added LiCl or NH(4)Cl, and various micellar solution properties, including critical micelle concentrations (cmc's), optimal micelle shapes, and average micelle aggregation numbers, are predicted. The predicted micellar solution properties agree reasonably well with the available experimental results.

Journal Article↗
PubMedDate not supplied

Advanced fluorocarbon-based systems for oxygen and drug delivery, and diagnosis.

Fluorocarbons and fluorocarbon-derived materials constitute a vast family of synthetic components that have a range of remarkable properties including exceptional chemical and biological inertness, gas-dissolving capacity, low surface tension, high fluidity, excellent spreading characteristics, unique hydro- and lipophobicity, high density, absence of protons, and magnetic susceptibility close to that of water. These properties lead to a diversity of products and applications as illustrated by those products that are already in advanced clinical trials, which comprise: 1) an injectable oxygen carrier, i.e. blood substitute, consisting of a fluorocarbon-in-water emulsion for use in surgery to alleviate the problems raised by the transfusion of homologous blood; the same emulsion is also being evaluated with cardiopulmonary bypass patients; 2) a neat fluorocarbon for treatment of acute respiratory failure by liquid ventilation; and 3) fluorocarbon-based or stabilized gas bubbles to be used as contrast agents for the assessment of heart function and detection of perfusion defects by ultrasound imaging. Proper selection of the fluorocarbon best suited for the intended application, formulation optimization, and advanced stabilization and processing procedures led to effective, ready-for-use products with minimal side-effects. Further highly fluorinated materials, including amphiphiles and various fluorocarbon-based colloidal systems that have potential as pulmonary, topical and ophthalmological drug delivery agents, and as skin protection barriers, are now being investigated. Such systems include drug-in-fluorocarbon suspensions, reverse water-in-fluorocarbon emulsions, oil-in-fluorocarbon emulsions, multiple emulsions, microemulsions, fluorocarbon gels, fluorinated liposomes, fluorinated tubules and other novel supramolecular systems.

Blood Substitutes↗
PubMed1975

Effect of fluorocarbon emulsions on the mechanical fragility of normal and sickle cells: in vitro studies.

Mechanical fragility measurements have been made in vitro on fluorocarbon emulsions mixed with normal and sickle cells in plasma to determine the effect of fluorocarbon. Emulsions of FC-80 with Pluronic F-68 were added to give final solutions of 0, 1, 5, 10, and 20% fluorocarbon emulsion. The effect of the fluorocarbon emulsion was observed in the presence and absence of oxygen. In the presence of oxygen, there was no effect of the fluorocarbon emulsion on the mechanical fragility of normal or sickle cells. In deoxygenated systems, however, there was significantly less hemoglobin in the plasma during the mechanical fragility test with fluorocarbon emulsion added to sickle cell blood. The normal blood was not affected by the fluorocarbon emulsion in the deoxygenated system. Five percent of fluorocarbon emulsion was required for a significant effect on the deoxygenated sickle cells. Since the effect of the fluorocarbon emulsion was in a deoxygenated condition, the effect is due to the presence of the fluorocarbon emulsion and not its oxygen carrying capability.

Anemia, Sickle Cell↗
PubMed1993

Fluorocarbon simulation of myocardial ischaemia and reperfusion: studies of relationships between force and intracellular calcium.

OBJECTIVE: The aim was to compare the effects of simulated ischaemia-reperfusion with those of hypoxia-reoxygenation in isolated muscle preparations from the ferret right ventricle. METHODS: Ischaemia was simulated using fluorocarbon immersion plus hypoxia. Intracellular calcium transients were determined from aequorin luminescence during isometric contractions. RESULTS: Hypoxia in fluorocarbon and physiological saline solution resulted in a similar reversible depression of the peak of the calcium transient. Peak active tension, however, was more depressed in fluorocarbon than in physiological salt solution. The dissociation between peak light and peak active tension was most pronounced on reoxygenation, with near complete recovery of peak light, while there was little recovery of tension in fluorocarbon. When fluorocarbon was then replaced by physiological salt solution, peak active tension recovered promptly. A prolongation of the decay of the calcium transient was seen in both fluorocarbon and physiological salt solution during hypoxia, which shortened promptly on reoxygenation. The time to the peak of the calcium transient was most prolonged during hypoxia in fluorocarbon and there was gradual recovery on reoxygenation. CONCLUSIONS: While some changes in the calcium transient during simulated ischaemia are rapidly reversible with reoxygenation (in fluorocarbon), suggesting an effect of hypoxia, others are incompletely reversed or only reversed with physiological salt solution, suggesting an effect of metabolite accumulation. The pronounced dissociation between peak light and peak active tension during reoxygenation in fluorocarbon is promptly reversed by changing to physiological salt solution, suggesting that metabolite retention in the postischaemic period may contribute to depressed myocardial function after reperfusion.

Animals↗
PubMed1994

Fluorocarbon emulsions--the stability issue.

Long-term room temperature stability of ready-to-use concentrated fluorocarbon emulsions is necessary in order to fully exploit the therapeutic potential of fluorocarbons. Consequently, considerable efforts have been directed at investigating the physical nature of such emulsions, the mechanisms which lead to their degradation and the means of counteracting these. The particles which constitute typical fluorocarbon/egg yolk phospholipid emulsions have been identified to be surfactant-coated fluorocarbon droplets and lipid vesicles. Better understanding has been gained on the formation, structure and evolution of these particles during processing and storage. This has led to optimized formulations and processing, better control of emulsion characteristics and significantly improved stability. Molecular diffusion (Ostwald ripening or transcondensation) has been shown to be the maun mechanism of degradation when particles are less than 1 micron in diameter, even for the highly concentrated (volume fraction of fluorocarbon up to 50%) second generation fluorocarbon emulsions. Significant emulsion stabilization has been accomplished by adding fluorochemicals which are both less volatile and less water soluble, and nevertheless have an organ dwell time acceptable for intravascular use. The rate of molecular diffusion can also be reduced by decreasing the fluorocarbon/water interfacial tension; this was effectively achieved with appropriate, well-defined fluorinated surfactants. A further, novel means of stabilizing fluorocarbon-in-water emulsions makes use of mixed fluorocarbon-hydrocarbon amphiphiles which act as molecular dowels to reinforce the adhesion between the fluorocarbon phase and the lipophilic zone of the surfactant film. Both long-term room temperature stability, and particle-size control over a large range of diameter, have been achieved by applying this principle. All in all it can be said that the challenge of producing injectable fluorocarbon emulsions with long-term room temperature particle size stability has been met.

Blood Substitutes↗
PubMed1977

Mass transfer properties of gases in fluorocarbons.

The solubility and diffusion coefficient of oxygen and carbon dioxide were measured in both the pure and emulsified of two fluorocarbons, perfluorotributylamine and perfluorobutyl perfluorotetrahydrofuran. The solubility coefficient and the diffusivity of oxygen in the pure form of the fluorocarbons decreased with decreasing partial pressure of Oxygen (PO2), but the solubility coefficient and the diffusivity of carbon dioxide were independent of its partial pressure. The solubility and diffusion of oxygen in the emulsified form of the fluorocarbons followed the pattern expected from the behavior of oxygen in the pure fluorocarbon. The experimental results suggest that there exists a physical and/or chemical interaction between oxygen and the fluorocarbons, and this interaction is more pronounced at partial pressures below 150 mm Hg. Comparisons of the oxygen content in the fluorocarbon emulsions with that in whole blood show that at PO2 of 760 mm Hg, the oxygen content in the fluorocarbon emulsions is approximately one-half that in whole blood, but at PO2 of 50-150 mm Hg, the oxygen content in the emulsions decreases to values which are less than one-tenth that of whole blood.

Carbon Dioxide↗
PubMed1985

Limitations of fluorocarbons in reducing myocardial infarct size.

The effects of the oxygen-carrier fluorocarbons on myocardial infarct size were assessed in non-exchange-transfused dogs subjected either to a 3-hour occlusion of the left anterior descending coronary artery (LAD) followed by 2 hours of reperfusion (protocol I) or to a 5-hour permanent LAD occlusion (protocol II). Fluorocarbon administration was begun 30 minutes after LAD occlusion and was continued over the entire period of ischemia. After 5 hours, the hearts were excised and areas of necrosis were visualized by triphenyl tetrazolium chloride staining while risk regions were assessed by radiolabeled microspheres injected after coronary occlusion just before the onset of therapy, and further, in protocol I, by thallium-201 perfusion imaging performed at the end of fluorocarbon administration. In protocol I experiments, the ratio of necrotic area to area at risk was 81 +/- 35% (mean +/- standard deviation) in control saline-treated dogs (n = 6) and 67 +/- 27% in fluorocarbon-treated dogs (n = 6) (difference not significant). There was no significant difference between risk regions measured after and before fluorocarbon treatment. In protocol II, the ratio of necrotic area to area at risk was 47 +/- 30% in control dogs (n = 5) and 63 +/- 29% in fluorocarbon-treated dogs (n = 5) (difference not significant). However, in control dogs, the ratio of necrotic area to area at risk increased from 47 +/- 30% in the dogs that underwent permanent occlusion to 81 +/- 35% in the group that underwent reperfusion (p less than 0.001) while this ratio was similar in the corresponding subsets of fluorocarbon-treated animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗