Ultrafiltration of Micellar Solutions in the Presence of Electrolytes

Micellar extraction coupled with ultrafiltration techniques represents a potentially attractive tool for the removal of different kinds of contaminants from waste waters. Even though most industrial streams to be treated contain large amounts of electrolytes, very little is known about the behavior of micellar solutions in ultrafiltration when large amounts of salts are present. This paper is concerned with an investigation of two cationic surfactants (cetyltrimethylammonium bromide (CTAB) and cetylpyridinium chloride (CPC)) and one anionic surfactant (sodium dodecylsulfate (SDS)) in the presence of several salts occurring in specific industrial processes (carbonates and hydrogenocarbonates, nitrites, nitrates). The ultrafiltration behavior of these systems, with individual salt concentrations up to 0.9 M, is studied from the viewpoint of the fluxes obtained, the amount of surfactant leakage and of the membrane "gel point." Two types of polymeric membranes with molecular weight cutoff of 10,000 Da are considered (cellulose and polysulfone), which show significantly different behaviors.

On the Behavior of Micellar Solutions in Tangential Ultrafiltration Using Mineral Membranes

Tangential ultrafiltration associated with the technology of mineral membrane is expected to offer several advantages compared to stirred cell ultrafiltration (often used at the laboratory level): (i) easier operating and cleaning procedures; (ii) better resistance to corrosion; (iii) reduced concentration polarization effects. The behavior of surfactant micelles, which can be used as the extracting phase in such processes, has been given little attention so far. The present work was aimed at investigating the behavior of different kinds of surfactants from the viewpoints of the permeate flux and of the amount of surfactant passing through the membrane. We have used two types of zirconium-titanium oxide membranes with molecular weight cutoff of 10,000 or 15,000 Da. The influence of parameters such as applied pressure, retentate flow rate, added salt, and value of pH was taken into consideration. The results obtained with cetylpyridinium chloride (CPC, cationic), sodium dodecyl sulfate (SDS, anionic), and polyethylene glycol tert-octylphenyl ether (Triton X-100, nonionic) are discussed in terms of their possible interactions with (or adsorption onto) the membranes and their supporting material.

Acute hemodynamic effects of an antitumoral agent: elliptinium. Involvement of histamine release.

This work reports a study of cardiovascular effects of elliptinium, a recently-acquired antitumoral agent, acutely administered i.v. in the dog. Its hemodynamic effects (10 parameters) are detailed, and their mechanism of action is investigated by antagonist administration and determination of blood and plasma histamine levels. Elliptinium induces vasodilation and tachycardia. The former is mainly due to histamine release, and a brief and slight release of prostaglandins; the latter is due to a reflex to hypotension and release of catecholamines. These results agree with others using various compounds of the ellipticine family and anthracycline antitumoral agents. They suggest treatment to prevent anaphylactoid side effects observed with this drug in man and they raise the question of the usefulness, in antitumoral agent, of histamine releasing properties.

Cardiac and vascular effects of elliptinium in guinea pigs. Involvement of a histaminergic mechanism.

This work reports a study of the effects of elliptinium on heart rate, arterial blood pressure and capillary permeability in guinea-pigs. The variations in capillary permeability are determined by spectrophotometric assay of skin Evans blue. Elliptinium induces dose-independent tachycardia and dose-related hypotension. For the highest dose (6 mg/kg), elliptinium induces lethal collapse . Elliptinium increases capillary permeability and this effect, particularly marked at 1 mg, i.d., is partially antagonized by mepyramine-cimetidine association. These results are discussed in comparison with those obtained with elliptinium on other parameters, with histamine and with different antitumoral agents. The increase in capillary permeability raises the question of its relevance to the anticancer activity of elliptinium.

[Cardiovascular effects of elliptinium. The mechanism of action]. / Effets cardiovasculaires de l'elliptinium. Approche du mécanisme d'action.

The effects of elliptinium were studied: Firstly, in the dog, in comparison with the effects of histamine, on heart rate and arterial blood pressure. Secondly, in guinea-pig isolated atria. When smaller doses were used (0.375; 0.75; 1.5 mg/kg) elliptinium only induced variations of heart rate. With the dose of 3 mg/kg hypotension and tachycardia appeared. The time-course of these effects was different from that of histamine (5 micrograms/kg): later onset and longer duration. Elliptinium was inactive in isolated guinea-pig atria, as observed in tracheal or digestive isolated smooth muscle. Thus, the cardiovascular activity of this antitumoral agent seems to implicate an indirect mechanism of action. This result is in accordance with the previous results obtained on bronchopulmonary system.