Peer Review Publications

Idit Amar-Yuli, Ellen Wachtel, Deborah E Shalev, Abraham Aserin, and Nissim. Garti. 2008. “Low Viscosity Reversed Hexagonal Mesophases Induced by Hydrophilic Additives.” Journal of Physical Chemistry B, 112, 13, Pp. 3971–3982. Abstract
This study reports on the formation of a low viscosity HII mesophase at room temp. upon addn. of Transcutol (diethylene glycol mono Et ether) or ethanol to the ternary mixt. of GMO (glycerol monooleate)/TAG (tricaprylin)/water. The microstructure and bulk properties were characterized in comparison with those of the low viscosity HII mesophase formed in the ternary GMO/TAG/water mixt. at elevated temps. (35-40 °C). We characterized the role of Transcutol or ethanol as inducers of disorder and surfactant mobility. The techniques used were rheol., differential scanning calorimetry (DSC), wide- and small-angle X-ray scattering (WAXS and SAXS, resp.), NMR (self-diffusion and 2H NMR), and Fourier transform IR (FTIR) spectroscopies. The incorporation of either Transcutol or ethanol induced the formation of less ordered HII mesophases with smaller domain sizes and lattice parameters at room temp. (up to 30 °C), similar to those found for the GMO/TAG/water mixt. at more elevated temps. (35-40 °C). On the basis of our measurements, we suggest that Transcutol or ethanol causes dehydration of the GMO headgroups and enhances the mobility of the GMO chains. As a result, these two small mols., which compete for water with the GMO polar headgroups, may increase the curvature of the cylindrical micelles and also perhaps reduce their length. This results in the formation of fluid HII structures at room temp. (up to 30 °C). It is possible that these phases are a prelude to the HII-L2 transformation, which takes place above 35 °C. [on SciFinder(R)]
Idit Amar-Yuli, Abraham Aserin, and Nissim. Garti. 2008. “Solubilization of Nutraceuticals into Reverse Hexagonal Mesophases.” Journal of Physical Chemistry B, 112, 33, Pp. 10171–10180. Abstract
The solubilization of four bioactive mols. with different polarities, in three reverse hexagonal (HII) systems has been investigated. The three HII systems were a typical reverse hexagonal composed of glycerol monooleate (GMO)/tricaprylin/water and two fluid hexagonal systems contg. either 2.75 wt. % Transcutol or ethanol as a fourth component. The phase behavior of the liq. cryst. phases in the presence of ascorbic acid, ascorbyl palmitate, D-$\alpha$-tocopherol and D-$\alpha$-tocopherol acetate were detd. by small-angle X-ray scattering (SAXS) and optical microscopy. Differential scanning calorimetry (DSC) and Fourier-transform IR (FT-IR) techniques were utilized to follow modifications in the thermal behavior and in the vibrations of different functional groups upon solubilizing the bioactive mols. The nature of each guest mol. (in both geometry and polarity) together with the different HII structures (typical and fluids) detd. the corresponding phase behavior, swelling or structural transformations and its location in the HII structures. Ascorbic acid was found to act as a chaotropic guest mol., localized in the water-rich core and at the interface. The AP was also a chaotropic guest mol. with its head located in the vicinity of the GMO headgroup while its tail embedded close to the surfactant tail. D-$\alpha$-tocopherol and D-$\alpha$-tocopherol acetate were incorporated between the GMO tails; however, the D-$\alpha$-tocopherol was located closer to the interface. Once Transcutol or ethanol was present and upon guest mol. incorporation, partial migration was detected. [on SciFinder(R)]
J Barauskas and T Nylander. 2008. “Lyotropic liquid crystals as delivery vehicles for good ingredients.” In Delivery Controlled Release Bioact. Foods Nutraceuticals, Pp. 107–131. Woodhead Publishing Ltd. Abstract
A review focuses on how the non-lamellar liq. cryst. phase can be turned into well-defined LCNP that can be used to entrap compds. with low aq. soly. as well as hydrophilic compds. It also discusses the stability of the compds. in terms of hydrolysis as well as what happens when these particles interact with an interface. [on SciFinder(R)]
CP Champagne and K Kailasapathy. 2008. “Encapsulation of probiotics.” In Delivery Controlled Release Bioact. Foods Nutraceuticals, Pp. 344–369. Woodhead Publishing Ltd. Abstract
A review discusses the encapsulation technologies for probiotics. However, technologies applied to probiotics are generally limited to gel particles, spray-coating, spray-drying, extrusion and emulsions. [on SciFinder(R)]
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)]
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, 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)]
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)]
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)]
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)]
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)]