All Publications

R Efrat, A Aserin, and N Garti. 2008. “On structural transitions in a discontinuous micellar cubic phase loaded with sodium diclofenac.” Journal of Colloid and Interface Science, 321, 1, Pp. 166–176. Abstract
An intermediate mesophase of lyotropic liq. cryst. structure from the ternary mixts. of glycerol monooleate, water, and ethanol was recently characterized in our lab. This mesophase, termed Q L, consists of discrete discontinuous micelles arranged in a cubic array. The Q L phase can solubilize very significant loads of water-insol. anti-inflammatory drug sodium diclofenac (Na-DFC). Close examn. of the internal structures of the lyotropic liq. structure upon increasing the solubilization loads reveals the existence of three structural transitions controlled by the Na-DFC levels. Up to 0.4 wt% Na-DFC, the Q L structure remains intact with some influence on the hydration of the headgroups and on the intermicellar forces. However, at 0.8 to 1.2 wt% Na-DFC, the discontinuous micellar cubic phase is transformed into a more condensed mesophase of a bicontinuous cubic phase. At \textgreater 1.2 wt% Na-DFC, the cubic phase is converted into a lamellar phase (L $\alpha$). Within 5.5 to 7.3 wt% Na-DFC the mesophase is progressively transformed into a less ordered lamellar structure. At ≥ 12 wt% Na-DFC crystals tend to ppt. out. At low Na-DFC concns. the drug behaves like a lyotropic or kosmotropic salt and can salt-out the surfactant from its water layer, but at higher levels it behaves like a hydrotropic, chaotropic salt and can salt-in the surfactant. The Na-DFC location and position within the interface as well as its polarization and partial ionization are strongly affected by its solubilization contents and the structure that it is inducing. In the cubic phase the drug is located less close to the hydration layer while once transition occurs it is exposed more to the water layer and the surfactant headgroups. [on SciFinder(R)]
Rivka Efrat, Deborah E Shalev, Roy E Hoffman, Abraham Aserin, and Nissim. Garti. 2008. “Effect of Sodium Diclofenac Loads on Mesophase Components and Structure.” Langmuir, 24, 14, Pp. 7590–7595. Abstract
We studied the effect of a model electrolytic drug on intermol. interactions, conformational changes, and phase transitions in structured discontinuous cubic QL lyotropic liq. crystals. These changes were due to competition with hydration of the lipid headgroups. Structural changes of the phase induced by solubilization loads of sodium diclofenac (Na-DFC) were investigated by directly observing the water, ethanol, and Na-DFC components of the resulting phases using 2H and 23Na NMR. Na-DFC interacted with the surfactant glycerol monoolein (GMO) at the interface while interfering with the mesophase curvature and also competed with hydration of the surfactant headgroups. Increasing quantities of solubilized Na-DFC promoted phase transitions from cubic phase (discontinuous (QL) and bicontinuous (Q)) into lamellar structures and subsequently into a disordered lamellar phase. Quadrupolar coupling of deuterated ethanol by 2H NMR showed that it is located near the headgroups of the lipid and apparently is hydrogen bonded to the GMO headgroups. A phase transition between two lamellar phases (L$\alpha$ to L$\alpha$*) was seen by 23Na NMR of Na-DFC at a concn. where the characteristics of the drug change from kosmotropic to chaotropic. These findings show that loads of solubilized drug may affect the structure of its vehicle and, as a result, its transport across skin-blood barriers. The structural changes of the mesophase may also aid controlled drug delivery. [on SciFinder(R)]
N Garti. 2008. “The future of controlled release and delivery technologies.” In Delivery Controlled Release Bioact. Foods Nutraceuticals, Pp. 450–464. Woodhead Publishing Ltd. Abstract
A review. In some countries health authorities are advising minimizing the use of insol. solid nanoparticles that have been shown to cause some significant damage to the healthy growth of various cells and to decrease the viability of others. However, companies and those dealing with future foods prefer to conc. on delivery methods and technologies and to refrain from using the term nanosized particles. All the technologies will involve utilization of new encapsulation and entrapment of bioactives and other food additives by advanced encapsulation micro- and nanovehicles. [on SciFinder(R)]
Nissim Garti, Abraham Aserin, and Roy. Hoffman. 2008. “System and methods for diffusion ordered spectroscopy.”. Abstract
The invention relates to a method for generating liq.-state diffusion order NMR spectroscopy (DOSY), method for minimizing the peak width in liq.-state DOSY, method of enhancing the sepn. between diffusion coeff. of compds. in liq.-state DOSY, a method for prepg. a system for generating liq.-state diffusion ordered DOSY of a sample, a method for prepg. a system for generating a liq.-state DOSY of a sample and kits for carrying liq.-state DOSY. [on SciFinder(R)]
Roy E Hoffman, Hilla Arzuan, Chava Pemberton, Abraham Aserin, and Nissim. Garti. 2008. “High-resolution NMR "chromatography" using a liquids spectrometer.” Journal of Magnetic Resonance, 194, 2, Pp. 295–299. Abstract
NMR spectroscopy is an excellent tool for the structural anal. of pure compds. However, for mixts. it performs poorly because of overlapping signals. Diffusion can be used to sep. compds. of widely differing mol. wt. but the amt. of sepn. is usually insufficient. Addn. of a solid medium, analogous to the stationary phase in chromatog., can preferentially slow the diffusion of some components of a mixt. permitting sepn. in the diffusion dimension. However, this would usually require a solid-state NMR spectrometer otherwise the signals would be too broad. Susceptibility matching the solvent to the solid medium yields a spectrum with narrow signals allowing the measurement of a DOSY spectrum with enhanced sepn. in the diffusion dimension. [on SciFinder(R)]
Anna Kogan, Inna Popov, Vladimir Uvarov, Shmuel Cohen, Abraham Aserin, and Nissim. Garti. 2008. “Crystallization of Carbamazepine Pseudopolymorphs from Nonionic Microemulsions.” Langmuir, 24, 3, Pp. 722–733. Abstract
Crystn. of carbamazepine (CBZ), an antiepileptic drug, pptd. from confined spaces of nonionic microemulsions was investigated. The study was aimed to correlate the structure of the microemulsion [water-in-oil (W/O), bicontinuous, and oil-in-water (O/W)] with the cryst. structure and morphol. of solid CBZ. The pptd. CBZ was studied by DSC, TGA, powder x-ray diffraction, single-crystal x-ray diffraction, SEM, and optical microscopy. The results suggest that the microstructure of the microemulsions influences the crystn. process and allows crystg. polymorphs that exhibit different crystal structure and habits. W/O nanodroplets orient the crystg. CBZ mols. to form a prism-like anhyd. polymorphic form with monoclinic unit cell and P21/n space group. Bicontinuous structures lead to platelike dihydrate crystals with orthorhombic unit cell and Cmca space group. The O/W nanodroplets cause the formation of needlelike dihydrate crystals with monoclinic unit cell and P21/c space group. The morphol. features of solid CBZ remain predetd. by the basic symmetry and parameters of its unit cell. Pptn. of CBZ pseudopolymorphs from supersatd. microemulsion is discussed in terms of oriented attachment that provides perfect packing of numerous sep. nucleated ordered nuclei of CBZ into microscale platelets and then into macroscopic crystals. Crystn. from microemulsion media enabling one to obtain the drug (CBZ) with predicted structure and morphol. should be of great significance for pharmaceutical applications. [on SciFinder(R)]
K Kailasapathy. 2008. “Encapsulation and controlled release of folic acid.” In Delivery Controlled Release Bioact. Foods Nutraceuticals, Pp. 331–343. Woodhead Publishing Ltd. Abstract
A review discusses the delivery of microencapsulated folates through food such as cheese and its controlled release. [on SciFinder(R)]
Anna Kogan, Ellina Kesselman, Dganit Danino, Abraham Aserin, and Nissim. Garti. 2008. “Viability and permeability across Caco-2 cells of CBZ solubilized in fully dilutable microemulsions.” Colloids and Surfaces, B: Biointerfaces, 66, 1, Pp. 1–12. Abstract
The viability and permeability of carbamazepine (CBZ) solubilized in fully dilutable non-ionic microemulsions across Caco-2 cells used as a model for intestinal epithelium. Maximum solubilization capacity (SC) of CBZ was detd. within water-in-oil (W/O), bicontinuous and oil-in-water (O/W) structures formed upon diln. The effect of the nature of the oil phase, surfactant type, and the ratio between the oil phase and surfactant on the quantity of solubilized CBZ, droplets size, the viability of the cells and drug permeability was elucidated. Several fully dilutable microemulsions based on pharma-grade ingredients can be loaded with very significant amts. of CBZ, and W/O microemulsions (10 wt% water) exhibit up to 3-fold higher solubilization capacity over the drug's soly. in oil (triacetin). CBZ in the O/W microemulsions (80 wt% water) exhibit up to 29-fold higher solubilization than in water, and the O/W droplets of the examd. systems are 9-11 nm in size, and the highest permeability was obtained in systems contg. triacetin/$\alpha$-tocopherol acetate/ethanol in 3/1/4 wt% ratio as oil phase and Tween 60 as surfactant. The replacement of $\alpha$-tocopherol acetate by $\alpha$-tocopherol inhibits CBZ release and replacement of a satd. chain of Tween 60 by an unsatd. (Tween 80) or shorter chain (Tween 40) inhibited drug release. The decrease in the oil phase to surfactant ratio leads to enhancement of drug release (diln. line 64 \textgreater diln. line 73). [on SciFinder(R)]
G Lafitte. 2008. “Structure of the gastrointestinal mucus layer and implications for controlled release and delivery of functional food ingredients.” In Delivery Controlled Release Bioact. Foods Nutraceuticals, Pp. 26–52. Woodhead Publishing Ltd. Abstract
A review discusses the compn. and the properties of the mucin mols. and the mechanism of adhesion of delivery vehicles to the mucus layer. The efficiency of a controlled-release formulation is subjected to the balance between the kinetics of its adhesion and the rate of erosion of the mucus. The influence of some of the mucin mols. and lipids is discussed. [on SciFinder(R)]
S.-J. Lee and DY Ying. 2008. “Encapsulation of fish oils.” In Delivery Controlled Release Bioact. Foods Nutraceuticals, Pp. 370–403. Woodhead Publishing Ltd. Abstract
A review describes the microencapsulation technologies and encapsulant materials used to deliver fish oils and the application of encapsulated fish oils in food products. It also discusses the benefits of fish oil and challenges of adding fish oils to foods. [on SciFinder(R)]
Hyoungill Lee, Josh Rivner, Jeffrey L Urbauer, Nissim Garti, and Louise. Wicker. 2008. “De-esterification pattern of Valencia orange pectinmethylesterases and characterization of modified pectins.” Journal of the Science of Food and Agriculture, 88, 12, Pp. 2102–2110. Abstract
Pectinmethylesterase (PME, E.C.1.1.11) isoenzymes from Valencia orange prepns. with different specific activities were used to de-esterify citrus and sugar beet pectins. Enzymic modification offers the opportunity to create pectins of tailored functionality and gelling ability. Based on NMR spectra, catalysis by all PME exts. produced block-wise de-esterification patterns in both citrus and sugar beet pectins. PME activity resulted in increased nos. of contiguous de-esterified groups and decreased nos. of contiguous esterified groups. De-esterification by PMEs increased the elastic property (G') of citrus and sugar beet pectins in the presence of calcium from 10 to 571 and from 0.05 to 201 Pa, resp. The results demonstrate the predilection of citrus PMEs toward block wise de-esterification of pectins and the relationship between calcium binding ability and de-esterification degree and patterning. Within a narrow range of de-esterification (37-48%) and with a narrow distribution of contiguous groups, PME modification did not markedly change gelling ability. At lower or higher de-esterification values, a 2-fold increase or 50-fold decrease, resp. in G' values was obsd. [on SciFinder(R)]
Dima Libster, Paul Ben Ishai, Abraham Aserin, Gil Shoham, and Nissim. Garti. 2008. “From the Microscopic to the Mesoscopic Properties of Lyotropic Reverse Hexagonal Liquid Crystals.” Langmuir, 24, 5, Pp. 2118–2127. Abstract
The authors aimed to explore a correlation between the microstructural properties of the lyotropic reverse hexagonal phase (HII) of the GMO/tricaprylin/phosphatidylcholine/H2O system and its mesoscopic structure. The mesoscopic organization of discontinuous and anisotropic domains was examd., in the native state, using environmental SEM. The topog. of the HII mesophases was imaged directly in their hydrated state, as a function of aq.-phase concn. and compn., when a proline amino acid was solubilized into the systems as a kosmotropic (water-structure maker) guest mol. The domain structures of several dozen micrometers in size, visualized in the environmental SEM, possess fractal characteristics, indicating a discontinuous and disordered alignment of the corresponding internal H2O rods on the mesoscale. On the microstructural level, SAXS measurements revealed that as H2O content (Cw) increases the characteristic lattice parameter of the mesophases increases as well. Using the H2O concn. as the mass measure of the mixts., a scaling relation between the lattice parameter and the concn. was found to obey a power law whereby the derived fractal dimension was the relevant exponent, confirming the causal link between the microscopic and mesoscopic organizations. The topog. of the HII mesophase is affected by the microstructural parameters and the compn. of the samples. Thermal anal. expts. involving these systems further confirmed that the behavior of H2O underpins both microscopical and mesoscopic features of the systems. Both the swelling of the lattice parameter and the mesoscopic domains is correlated to the bulk H2O concn. in the H2O rods. [on SciFinder(R)]
YD Livney. 2008. “Complexes and conjugates of biopolymers for delivery of bioactive ingredients via food.” In Delivery Controlled Release Bioact. Foods Nutraceuticals, Pp. 234–250. Woodhead Publishing Ltd. Abstract
A review discusses the aspects of complexes and conjugates of biopolymers related to the delivery of functional components via foods. The advantages of complexes and conjugates of proteins and polysaccharides used as building blocks for delivery systems are many. [on SciFinder(R)]