Publications by Year: 1995

Magdassi S, Toledano O, Zakay-Rhones Z. Formation of novel colloidal immunoclusters by surface active antibodies. J. Colloid Interface Sci.Journal of Colloid and Interface Science. 1995;175 (2) :435 - 9.Abstract
Surface active antibodies were formed by covalent attachment of hydrophobic groups to IgG mols. The modification was carried out at various degrees of attachment and various chain lengths. These modified antibodies spontaneously formed new colloidal micelle-like particles, immunoclusters, which were viewed with a transmission electron microscope and evaluated by light scattering. The size of the immunoclusters increased while either degree of attachment or chain-length were increased, and the biol. activity decreased with an increase of degree of modification. [on SciFinder(R)]
Magdassi S, Rones ZZ, Linevitz M, Shanberg O.; 1995. Method and pharmaceutical compositions for drug targeting.Abstract
A pharmaceutical compn. comprising an oil/water emulsion wherein the oil droplets contain a drug in dissolved or dispersed or solubilized form. The droplets are further coated with adsorbed native or modified antibodies which provide targeting of the droplets and the drug. The process for prepg. this compn. comprises the steps of dissolving or dispersing a drug in an oil phase, prepg. an oil/water emulsion, obtaining surface-active antibodies by chem. or phys. attachment of hydrophobic groups to the antibodies, and mixing the surface-active antibody with the emulsion. The targeting of emulsion droplets to specific cells was demonstrated by using herpes virus (HSV-1) cells. [on SciFinder(R)]
Magdassi S, Vinetsky Y. Microencapsulation of O/W emulsions by formation of a protein-surfactant insoluble complex. J. MicroencapsulationJournal of Microencapsulation. 1995;12 (5) :537 - 45.Abstract
A method for obtaining microcapsules of oil droplets by the formation of an insol. complex of protein-surfactant is described. The gelatin type A studied, which is pos. charged at the pH range studied, may form insol. and sol. complexes with sodium dodecyl sulfate (SDS), an anionic surfactant. The binding isotherms were studied and the specific molar ratios of SDS to gelatin, in which the insol. complex is formed, was detd. These specific ratios also led to the formation of microcapsules, in which the wall encapsulating the oil droplets, is composed of the insol. gelatin SDS complex. [on SciFinder(R)]
Magdassi S, Rones ZZ, Toledano O.; 1995. Antibody aggregates and hydrophobic drug or marker molecule pharmaceutical and diagnosis compositions for drug targeting.Abstract
The new pharmaceutical and diagnostic compns. comprise antibody-aggregates and hydrophobic drug or marker mols. The drug or marker mols. are solubilized inside micelle-like antibody-aggregates. In a process for prepg. such types of compns., hydrophobic residues are attached to the antibodies in the presence of a surface active agent. After removal of this agent the hydrophobic drug or marker mols. are solubilized inside the resulting antibody aggregates. A method for targeting mols. towards specific cells and sites within a living body is also disclosed. [on SciFinder(R)]
Levy N, Garti N, Magdassi S. Flocculation of bentonite suspensions with cationic guar. Colloids Surf., AColloids and Surfaces, A: Physicochemical and Engineering Aspects. 1995;97 (2) :91 - 9.Abstract
Cationic guar gums of varying molar mass and charge d. were synthesized and tested as flocculants for bentonite suspensions. The gums were fragmented using ammonium persulfate as a degrading agent, followed by pptn. of the products with ethanol. Cationic charge was added to the guar mol. by reacting it with 2,3-epoxypropyltrimethylammonium chloride. Flocculant performance was assessed by detg. the extent of polymer adsorption, by measuring both residual turbidities of the resulting supernatants and the changes in the particles' electrophoretic mobility (EM). Increasing the flocculant charge d. causes the optimal flocculation concn. (OFC), as well as the efficient flocculant concn. range, to be reduced. Above this range restabilization occurs. The OFC (for highly modified guar) is also the concn. at which the particles' EM is zero. It was found that decreasing the mol. wt. of the guar (at the same charge d.) increases the OFC and decreases the electrophoretic mobility of the clay particles in the overdose range. [on SciFinder(R)]
Magdassi S, Sheinberg O, Zakay-Rones Z. Formation and properties of surface-active antibodies. In: Proteins at Interfaces II- ACS Symposium Series. Vol. 602. American Chemical Society ; 1995. pp. 533 - 40.Abstract

Surface active antibodies were formed by covalent attachment of hydrophobic groups to the IgG mol. The modified antibodies reduced surface tension and adsorbed onto emulsion droplets at surface concns. higher than the native antibody. The chem. modification led to a decrease in the biol. activity; however, at specific conditions, surface-active antibodies, which retained their recognition ability, could be formed. By using these antibodies, a new emulsion, which has a specific recognition ability for HSV-1 infected cells, was formed. [on SciFinder(R)]

Sela Y, Magdassi S, Garti N. Release of markers from the inner water phase of W/O/W emulsions stabilized by silicone-based polymeric surfactants. J. Controlled ReleaseJournal of Controlled Release. 1995;33 (1) :1 - 12.Abstract

Silicone based surfactants were used as stabilizers for W/O/W double emulsions with unusual mech. stability. W/O/W multiple emulsions contg. several markers were prepd. The entrapped markers were: (1) halide salts, (2) a typical drug, ephedrine hydrochloride, and (3) KNO3 (water sol. fertilizer). Good solute trapping (95% yield of prepn.) with slow release rates through the liq. oil membrane (60% release after 30 days), were obtained. The halides, with the exception of iodide, showed almost the same typical slow release rates to the outer water phase. The release rates of the ephedrine hydrochloride and KNO3 were faster than that of the halides. The results suggested that multiple emulsions based on silicone surfactants can be used as slow release systems for agricultural applications. Up to 20 wt% of the total concn. of the hydrophobic silicone-based emulsifier (E1 - the inner emulsifier) was replaced by Span 80. As a result, water was entrapped in the oil phase, suggesting formation of reverse micelles in the presence of Span 80, explaining, in part, the release kinetics of the halides. The release seems to be composed of three sep. stages: lag time, fast release and "no release". The release mechanism seems to comply, in part, with a transport mechanism involving "reverse micelles" and is also dependent on the hydrophobicity of the marker. The more hydrophobic markers (the drug and iodide) seem to be released also by "direct diffusion of the mol. through the oil" in addn. to their release through the reverse micelles. [on SciFinder(R)]