Publications by Year: 1996

S.Magdassi, Vinetsky Y. Microencapsulation of O/W Emulsions by Proteins. In: Benita S Microencapsulation Methods and Industrial Applications. New York: Dekker ; 1996. pp. 21-33.
Magdassi S, Mumcuoglu K, Bach U.; 1996. Method of preparing natural oil-containing emulsions and microcapsules and its uses.Abstract
The invention relates to a process for prepg. a chitosan-contg. aq. emulsion of an oil comprising the steps of (a) forming an oil-in-water emulsion by homogenizing the oil into an aq. soln. contg. an anionic emulsifier; and (b) adding to the emulsion obtained in (a) an aq. chitosan soln. while continuously homogenizing the mixt. to give a stable emulsion. In further aspect the invention relates to a process for the microcapsulation of fine oil droplets. The invention also relates to sustained-release biodegradable prepns. comprising as active ingredient vitamin E or a UV radiation photoprotectant or a lice repelling agent comprising at least one natural oil or natural oil component thereof and further comprising an anionic emulsifier and chitosan. A lice-repelling emulsion contained rosemary oil 15, chitosan 0.5, citric acid 5, lecithin 0.35, and water 79.15%. The final pH of the emulsion was 3.5 and the emulsion was stable for ≥8 mo at room temp. When the emulsion was applied to human hair fibers, the chitosan microcapsules contg. rosemary oil adhered well to the fiber. [on SciFinder(R)]
Eyal AM, Kotlyar S, Apfelbaum F, Magdassi S, Braun S.; 1996. Process for the preparation of long-chain alkyl glycosides.Abstract
The invention provides a process for the prepn. of long-chain alkyl glycosides, comprising reacting a glucose-contg. reactant and a C8-C18 fatty alc. in the presence of a glucosidase and a reaction promoter effective to promote the formation of the alkyl glycoside when the promoter is present in an amt. of <∼50% of the total reaction mixt. [on SciFinder(R)]
Mumcuoglu KY, Galun R, Bach U, Miller J, Magdassi S. Repellency of essential oils and their components to the human body louse, Pediculus humanus humanus. Entomol. Exp. Appl.Entomologia Experimentalis et Applicata. 1996;78 (3) :309 - 314.Abstract
Five essential oils and nine of their components were compared to di-Et toluamide (DEET) for their repellent activity against the human body louse, Pediculus humanus humanus. The abs. or intrinsic repellency of the compds. was tested by applying the repellent to corduroy patches and comparing them with untreated patches. The most effective repellents were DEET and citronella, whose activity lasted at least 29 days. The activity of rosemary lasted at least 18 days and that of eucalyptus more than 8 days. The repellent activity of the oil components such as citronellal and geraniol lasted more than 15 and 8 days, resp. DEET remained effective at a diln. of 1:32, geraniol at 1:8, citronella at 1:4 and rosemary and citronellal at 1:1. The comparative or std. repellency of the candidate repellents was examd. with the aid of a new screening technique using hairs treated with ammonium bicarbonate which is attractive to lice. Using this technique it could be shown that the repellent activity of citronella and geraniol lasted 2 days and that of rosemary and citronellal for only one day. DEET was active for less than one day. Serial dilns. of these substances also revealed that citronella was the most potent repellent for lice, followed by citronellal, rosemary, geraniol and DEET. The differences however, were not significant. [on SciFinder(R)]
Magdassi S, Toledano O, Zakay-Rones Z. Solubilization in colloidal immunoclusters. J. Colloid Interface Sci.Journal of Colloid and Interface Science. 1996;184 (2) :360 - 364.Abstract
Micelle-like clusters of antibody mols. were prepd. by covalent attachment of various hydrophobic groups to the protein mols. These colloidal clusters were capable of solubilizing two hydrophobic probes, while the solubilizate:solubilizer molar ratio was dependent on the chain length of the hydrophobic groups, the degree of modification, and have, on the size of the colloidal clusters. By using a fluorescent solubilizate, it was demonstrated that the immunoclusters may have a specific recognition ability. [on SciFinder(R)]
Magdassi S, Editor. Surface Activity of Proteins: Chemical and Physicochemical Modifications. Dekker; 1996 pp. 327 pp.
Magdassi S, Rodel B-Z. Flocculation of montmorillonite dispersions based on surfactant-polymer interactions. Colloids Surf., AColloids and Surfaces, A: Physicochemical and Engineering Aspects. 1996;119 (1) :51 - 56.Abstract
A two-step flocculation process is described in which a polycation (polydiallyldimethylammonium chloride) is adsorbed on to neg. charged montmorillonite particles, followed by the addn. of an anionic surfactant [sodium dodecyl sulfate (SDS)]. At a 1:1 molar ratio, optimal flocculation is obtained owing to the formation of an insol. surfactant-polymer complex in the presence of the particles. The pptn. of the insol. complex is also dependent on the SDS and polymer concns., and occurs at a 1:1 SDS:monomer molar ratio. From adsorption isotherms of the polymer-particle and surfactant-polymer systems, the adsorption energy was calcd. and subsequently a flocculation mechanism is suggested. [on SciFinder(R)]
Kamyshny A, Reuveni T, Magdassi S. Formation and properties of horseradish peroxidase colloidal clusters. J. Colloid Interface Sci.Journal of Colloid and Interface Science. 1996;181 (2) :470 - 475.Abstract
Hydrophobic modification of horseradish peroxidase by fatty acid esters (C8, C12, C16, C18) of N-hydroxysuccinimide was carried out. The degree of modification increases with an increase in the ester:enzyme molar ratio and reaches a maximal value of four modified amino groups when this ratio is 150:1. Covalent attachment of hydrophobic groups to the peroxidase mols. leads to a spontaneous formation of micelle-like colloidal clusters, which have a mean diam. of 65 nm at the maximal degree of modification by C16-ester. The fraction of the enzyme mols. which forms clusters depends on both the length of the attached hydrophobic chain and the degree of modification. The colloidal clusters, which are composed of the modified peroxidase, have about 80 and 50% lower enzymic activities for C12- and C16- modified enzymes. [on SciFinder(R)]
Magdassi S, Vinetsky Y, Relkin P. Formation and structural heat-stability of β-lactoglobulin/surfactant complexes. Colloids Surf., BColloids and Surfaces, B: Biointerfaces. 1996;6 (6) :353 - 362.Abstract
The binding of two model surfactants, SDS and dodecyltrimethylammonium bromide to β-lactoglobulin was studied at room temp. and the thermal stability of the resulting complexes was evaluated by differential scanning calorimetry (DSC) measurements. Binding isotherms indicated both ionic and hydrophobic interactions depending on both the charge of the protein and surfactant at different pHs and on the binding molar ratios of surfactant to the globular protein. Zeta potential measurements indicated charge neutralization of the protein, under suitable conditions, which also lead to aggregation and pptn. of the proteins. Surface tension measurements indicated similarity between the two types of oppositely charged protein-surfactant complexes and a difference between them when protein and surfactants are similarly charged. DSC measurements revealed different behavior in protein conformation in the presence of the two surfactants. The results obtained at room temp. and upon heating are discussed in terms of the nature of the surfactant/protein interactions involved in the complex formation. [on SciFinder(R)]
Magdassi S, Vinetsky Y. Microencapsulation of oil-in-water emulsions by proteins. Drugs Pharm. Sci.Drugs and the Pharmaceutical Sciences. 1996;73 (Microencapsulation) :21 - 33.Abstract
A review with 33 refs. Methods of encapsulation, surface activity of proteins, and possible film-forming proteins in drug delivery are discussed. [on SciFinder(R)]
Cohen S, Magdassi S. Chemiluminescence in Microemulsions: Effect of Phase Composition. LangmuirLangmuir. 1996;12 (16) :3759 - 3762.Abstract
Chemiluminescence (CL) reactions were studied in a model system based on a phase diagram which was composed of Triton X-100, 2-butanol, toluene, and H2O. The CL reaction was achieved by using trichlorophenyl oxalate, H2O2, and perylene as the fluorophore. The intensity of light (I0) and t1/2 depend on both reactant concns. and phase compn. The CL reaction was conducted in W/O microemulsions, and an inverse relation between I0 and t1/2 was found. These two parameters could also indicate the transition from a W/O (water-in-oil) emulsion to a W/O microemulsion. The effect of medium polarity was evaluated by fluorescence, absorbance, and chemiluminescence spectra. [on SciFinder(R)]
Ma'or Z, Magdassi S, Efron D, Yehuda S. Dead Sea mineral-based cosmetics--facts and illusions. Isr J Med SciIsrael journal of medical sciences. 1996;32 Suppl :S28-35.Abstract
Modern Dead Sea cosmetics have developed in order to meet the demands of new regulations, technical opportunities, and today's consumer expectations for higher quality standards and proven performance. As an example of the application of this approach, the authors describe the development of a new cosmetic formulation, based on "Osmoter", a special Dead Sea mineral composition, and the evaluation of this formulation's effect on the depth of skin wrinkles, by a controlled assay. Possible mode of action is discussed.[on SciFinder (R)]
Magdassi S, Toledano O. Enhanced Hydrophobicity: Formation and properties of surface-active proteins. In: Surf. Act. Proteins. Dekker ; 1996. pp. 61 - 90.Abstract

A review with 86 refs. on detg. and modifying hydrophobicity of proteins to enhance surface activity. [on SciFinder(R)]

Magdassi S, Kamyshny A. Surface activity and functional properties of proteins. In: Surf. Act. Proteins. Dekker ; 1996. pp. 1 - 38.Abstract

A review with 189 refs. [on SciFinder(R)]