Glycol Groups Research Articles

Aggregation of 4,8,12-Triazatriangulene Cation with Amphiphilic Side Chains: Emission Properties in Solution, in Aggregates, and in the Solid State

A 4,8,12-triazatriangulene (TATA) cation derivative bearing tetra(ethylene glycol) group was synthesized by direct functionalization of the TATA framework at the 2-, 6-, and 10-positions. Emission properties of the amphiphilic TATA derivative in three different environments—in the monomer state, in aggregates formed in aqueous media, and in the solid state—were carefully analyzed based on the radiative (kf) and nonradiative (knr) rate constants. We found that the fluorescence quenching of the TATA cation derivative upon aggregation is dominantly attributed to the decrease in the kf value but not to the change in the knr value.

Poly(fluorene phenylene) Graft Copolymer As a Novel Binder with Polyvinylpyrrolidone for High-Capacity Silicon Anode in Lithium-Ion Batteries

Rechargeable lithium ion batteries (LIB) have been vastly used in portable devices like cellular phones, laptops, tablets and also in electric vehicles because of their relatively high energy density, good power performance and cycle life. Carbonaceous negative electrode materials, especially graphitic carbons are conventionally used as anode materials at LIBs due to their good cycle-ability and low stable discharge voltage plateau. However, graphite has a low Li atomic density at full Li capacity in carbon intercalation compound (LiC6) which leads to lower theoretical capacity (372 mAh/g). Therefore, different types of anode active materials have been investigated as an alternative to graphite in order to achieve higher capacities. Among them, silicon (Si) is one of the most promising candidate as an anode active material because of its high theoretical capacity (more than 3500 mAh/g at room temperature) and low average discharge potential (∼0.5 V vs Li/Li+).Unfortunately, huge volume expansion (310% at full lithiation of Si) due to the lithium ion diffusion during the lithiation/delithiation process causes drastic capacity fade because of the high internal stresses, loss of electrical contact and the formation of non-electronic and ionic conductive passivation film between the anode surface and electrolyte. Low electrical conductivity of silicon is also another problem that remarkably hinders the rate performance. In the present work, above mentioned shortcomings are overwhelmed by incorporating tri(ethylene glycol) (TEG) groups over phenylene base units as side chains on the framework of the PFP based conductive polymer. Polyvinylpyrrolidone (PVP) was also used as adhesive to enhance the property of binding, thus decreasing stress-induced cracks. The synthesis was achieved through Suzuki polycondensation reaction in the presence of Pd(PPh3)4 catalyst by using independently prepared TEG functionalized dibromo benzene in conjunction with dioctylfluorene-diboronic acid bis(1,3-propanediol) ester. The obtained conductive and flexible polymer was used as a binder for Si-anode with high performance. It was demonstrated that the designed and fabricated binder polymer with multi-functionality displays a high electronic conductivity, mechanical strength, high polarity, adhesion, and more importantly, the electrolyte uptake arising from its excellent ductility. Figure 1

POSS Moieties with PEG Vertex Groups as Diluent in Polyurethane Elastomers: Morphology and Phase Separation

Polyhedral oligomeric silsesquioxane moieties with poly(ethylene glycol) groups attached on the cage (PEG–POSS) were blended with an elastomeric polyurethane matrix, in contents up to 10 wt %. Several experimental techniques in agreement with each other show that the PEG–POSS moieties disperse well on the molecular level and act as diluents plasticizing the molecular dynamics. Although the degree of microphase separation is only weakly affected in all the compositions, changes in the macromorphology related to the POSS moieties have an impact on the matrix properties, decreasing the storage modulus. The PEG–POSS themselves display segmental dynamics, glass transition, and crystallinity; however, none of these properties are observed in the blends, providing additional support for excellent miscibility with the matrix. The results are compared to those of previous works where different synthesis approaches resulting in different POSS topologies were used.

Separation of pegylated recombinant proteins and isoforms on CIM ion exchangers.

Protein pegylation is a process of covalent attachment of a polyethylene glycol (PEG) group to the protein tertiary structure that can "mask" the agent from the immune system and also increases the hydrodynamic size of the agent. Usually the pegylation prolongs the protein stability in the organism due to reduced renal clearance and provides superior water solubility to hydrophobic molecules. The mono-pegylated form of protein is usually prefered for medical applications. Different conditions with different PEG reagents have to be tested to find optimal pegylation procedure with specific protein. The goal of this study was to prepare screening method for separation of random mono-pegylated protein. Cytochrome C and beta lactoglobulin were pegylated with four reagents and a complete screening of several chromatographic monoliths in ion exchange mode with different buffers was performed to optimaly separate each mono-pegylated protein. The screening method was developed that produces optimal separation of target pegylated protein on CIM monoliths. Because of short chromatographic run time, CIM monoliths are perfect candidates to test alot of parameters. The results obtained show that each protein has its own unique separation parameters (pH, ionexchange ligand, buffer type). Two biopharmaceuticals were isolated using protocol: super human leptin antagonist (SHLA) was purified from inclusion bodies and mono-pegylated super mouse leptin antagonist (SMLA) from pegylated mixture. During study it was observed that the convective interaction media (CIM) monoliths additionally discriminate between protein isoforms pegylated on different sites in 3D structure of the protein.

Optical limiting effects of cyano substituted distyrylbenzene derivatives

Two liquid cyano substituted distyrylbenzene derivatives (P2 and P4) have been synthesized by incorporating two tetraethylene glycol groups into the prototype scaffolds of 2,5-bis(4-(diethylamino)styryl)terephthalonitrile (P1) and 2,2'-(1,4-phenylene)bis(3-(4-(diethylamino)phenyl)acrylonitrile) (P3), respectively, for increasing their solubilities in liquid and solid substrates. The linear photophysical properties, optical/thermal stabilities and optical limiting behaviors of P1–P4 have been investigated. Results show that both P2 and P4 have significant optical limiting behaviors on 800 nm laser pulses and high thermal stabilities. However, only P4 whose cyano groups substituted on the vinylene bond exhibits good optical stability, while P2 whose cyano groups substituted on the central phenylene ring presents gradual photobleaching under illumination. Through doping P4 into a solid epoxy resin, effective optical limiting devices to 800 nm pulsed laser are fabricated.

Noncontact AFM First-Principles Simulations of Functionalized Silicon Tips on the Montmorillonite (001) Surface

The interaction between functionalized silicon probe tips and the montmorillonite (MMT) surface was studied through density-functional theory (DFT) with the van der Waals DF (vdW-DF) to include the contribution of the vdW forces in the interaction energy of the tip/MMT interface. On the basis of the noncontact AFM (NC-AFM) technique, we modeled an explicit Si probe tip that was functionalized with sulfonic acid (SA) and ethylene glycol (EG) groups present in polymeric surfactants. Accordingly, we obtained the short-range microscopic forces to investigate the hysteresis mechanism due to the approach and retraction processes of the tips as well as tip tilt, usually leading to the topographic and dissipation image contrasts. Furthermore, it was possible assert the influence of different hydrophilicity degrees toward the oxygen sites at the silicate sheet of the MMT (001) surface, which is related to important processes of surface interaction. Our results showed both SA and EG hydrophilic functional groups ar...

Synthesis, characterization, optical and electrical properties of bis(phenylvinyl)anthracene-based polymers

A series of bis(phenylvinyl)anthracene-based polymers containing different lengths of polar ethylene glycol groups in the main chain (P1–3) were efficiently synthesized by Wittig polycondensation. These polymers are fully soluble in volatile solvents, which helped a lot to obtain high quality films. Moreover, these semi-conducting materials exhibited semi-crystalline morphology with relatively high glass transition temperature. In this article, the UV–visible absorption and fluorescence properties of P1–3 were studied consequently both in solution and as thin solid film: tan absorption-onset at 433 nm was observed and all these bis(phenylvinyl)anthracene-based polymers (P1–3) show a blue emission in solution, fluorescence quantum efficiencies being respectively 52% for P1, 75% for P2 and 67% for P3. In addition, the HOMO/LUMO energy levels were evaluated by cyclic voltammetry measurements and indicate a p-type semi-conducting materials. Finally, the electrical properties of P1–3 were investigated by recording current-tension characteristics and these experimental results were modeled by the current space-charge-limited (SCLC) mechanism.

Optical limiting property of a liquid malononitrile derivative on 800 nm laser pulses

A new liquid malononitrile derivative (LBDBP) has been synthesized by incorporating four tetraethylene glycol groups into the prototype scaffold of 2-[Bis-(4′-diethylamino-biphenyl-4-yl)-methylene]-malononitrile (BDBP). The linear photophysical properties, optical/thermal stabilities and optical limiting behaviors of LBDBP and BDBP have been investigated. The results show that LBDBP has equivalent optical/thermal stability but much better solubility compared with BDBP. Its saturation concentration in DMF is increased to 0.075 M, while the corresponding datum for BDBP is only 0.01 M. The improved solubility of LBDBP insures a very significant optical limiting behavior. The saturated DMF solution of LBDBP can significantly reduce the intensity fluctuation of laser pulses in an 800 nm laser setup.

Structure of alumina-silica nanoparticles grafted with alkylphosphonic acids in poly(ethylacrylate) nanocomposites

Alumina-coated silica nanoparticles (NPs) grafted with phosphonic acids of different hydrophobicity were used as filler in poly(ethylacrylate) nanocomposites. Phosphonic acids bearing short alkyl chains or a diethylene glycol group have been grafted at densities up to 3.2 P/nm2 on NPs (20 nm) dispersed in water. Nanocomposites at particle fractions up to 10 vol% have been formulated by casting from the colloidal mixtures of modified NPs and nanolatex in water. The dispersion of the NPs in the polymer matrix has been studied by TEM combined with small-angle scattering, evidencing aggregation of NPs. TEM shows micrometer-scale inhomogeneities depending on the surface/polymer matrix compatibility. For the local interparticle correlations, a quantitative analysis of the intensity based on the mapping onto the effective structure factor of polydisperse hard spheres is developed. This mapping allows the model-free determination of the internal volume fraction of aggregates, termed compacity κ, to between 10% and 30%, compatible with the TEM analysis. κ is found to increase for the higher particle volume fractions, to decrease with grafting density, and to be mostly independent of the nature and mass of the graft. Preliminary evidence for an improved compatibility of grafted with respect to bare NPs is found, as opposed to their aqueous precursor suspensions where some pre-aggregation is induced by grafting.

Protective effects of Cuminum cyminum L. essential oil on ethylene glycol induced nephrolithiasis in mice

Objective: To investigate the protective effect of Cuminum cyminum (C. cyminum) essential oil on ethylene glycol induced nephrolithiasis in mice. Methods: The study comprised of the following four different groups of six mice: ethylene glycol group, C. cyminum group, treatment group and normal group. The levels of blood urea nitrogen and creatinine were analyzed and the kidney samples from all the animals of each group were stained with haematoxylin and eosin. Results: Treatment group revealed mild tubular degeneration without formation of calcium oxalate crystals and protein deposition. There were no significant differences between serum levels of blood urea nitrogen and creatinine in treatment and normal groups. Conclusions: It seems that C. cyminum essential oil significantly decreased formation of calcium oxalate crystals and the growth of renal calculi in different parts of the tubules.

MP67-07 THE PROTECTIVE EFFECTS OF PROPOLIS ON OXIDATIVE STRESS AND CRYSTAL DEPOSITION WITH HYPEROXALURIA INDUCED TUBULAR CELL INJURY IN RAT MODEL

You have accessJournal of UrologyStone Disease: Basic Research & Pathophysiology II1 Apr 2016MP67-07 THE PROTECTIVE EFFECTS OF PROPOLIS ON OXIDATIVE STRESS AND CRYSTAL DEPOSITION WITH HYPEROXALURIA INDUCED TUBULAR CELL INJURY IN RAT MODEL Kamil Fehmi Narter, Alper Kafkasli, Oguz Ozturk, Ozgur Yazici, Bilal Hamarat, Sukran Sarikaya, and Kemal Sarica Kamil Fehmi NarterKamil Fehmi Narter More articles by this author , Alper KafkasliAlper Kafkasli More articles by this author , Oguz OzturkOguz Ozturk More articles by this author , Ozgur YaziciOzgur Yazici More articles by this author , Bilal HamaratBilal Hamarat More articles by this author , Sukran SarikayaSukran Sarikaya More articles by this author , and Kemal SaricaKemal Sarica More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2016.02.1323AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Oxidative stress (OS) can be effective in the kidney stone formation. We aimed to evaluate the degree of crystalization (CaOx) as well as oxidant (ROS)/antioxidant status in the kidney tissues, serum samples and possible protective effect of verapamil (V) or propolis (P)(honey-bee antioxidant product) on hyperoxaluric rat model. METHODS A total of 60 SD rats (350 g) were divided into the 6 study groups contained 8 rats during early (7 days) and late (28 days) follow-up. Control group;12 rats. Ethylene glycol (EG) group (0.75%, drinking water) Verapamil group (EG+1 mg/kg V, feeding tube) Propolis group (EG+50 mg/kg P, feeding tube) Histopathological evaluations of crystalization in kidney tissue;Light microscopy 10% formalin/24 h, paraffin,4-lm- section, stain HE). After the homogenization tissue samples were equilibrated to 1 mg tissue/1 ml Phosphate Buffered Saline. Blood samples were centrifuged in 3000 rpm/5 min. ELISA tests of catalase (CAT), superoxide dismutase (SOD), total glutathione (GSH), nitric oxide (NO), malonil dialdehid (MDA), total anti-oxidant capacity (TAOC) have been used to evaluate oxidant/antioxidant status of tissue and serum samples (YH-Biosearch). The statistical analyses;GraphPad Prism 6.0 software, multiple t-tests and statistical significance the Sidak-Bonferroni method, α=1.000%. RESULTS Statistically significant results were indicated on graphs. ELISA tissue and serum levels (Fig.1) of all parameters were shown. Crystalization (CaOx) in V group (mild), in P group (Limited) and in without any protective agent (EG group)(extensive, dense) at late phase (Fig 2). Although, both V and P did tend to limit the degree of crystaliazation, it was significantly lower in P group than V group. CONCLUSIONS As a result of our study, the limitation of both crystalization and OS might be instituted by propolis. As clinical application of propolis in the prophylaxis of stone disease might limit the formation, especially in recurrent stone formers. © 2016FiguresReferencesRelatedDetails Volume 195Issue 4SApril 2016Page: e883 Advertisement Copyright & Permissions© 2016MetricsAuthor Information Kamil Fehmi Narter More articles by this author Alper Kafkasli More articles by this author Oguz Ozturk More articles by this author Ozgur Yazici More articles by this author Bilal Hamarat More articles by this author Sukran Sarikaya More articles by this author Kemal Sarica More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Interaction of the Hydrophobic Tip of an Atomic Force Microscope with Oligopeptides Immobilized Using Short and Long Tethers.

We report an investigation of the adhesive force generated between the hydrophobic tip of an atomic force microscope (AFM) and surfaces presenting oligopeptides immobilized using either short (∼1 nm) or long (∼60 nm) tethers. Specifically, we used either sulfosuccinimidyl-4-(N-maleimidomethyl)cyclohexane-1-carboxylate (SSMCC) or 10 kDa polyethylene glycol (PEG) end-functionalized with maleimide and N-hydroxysuccinimide groups to immobilize helical oligomers of β-amino acids (β-peptides) to mixed monolayers presenting tetraethylene glycol (EG4) and amine-terminated EG4 (EG4N) groups. When SSMCC was used to immobilize the β-peptides, we measured the adhesive interaction between the AFM tip and surface to rupture through a single event with magnitude consistent with the interaction of a single β-peptide with the AFM tip. Surprisingly, this occurred even when, on average, multiple β-peptides were located within the interaction area between the AFM tip and surface. In contrast, when using the long 10 kDa PEG tether, we observed the magnitude of the adhesive interaction as well as the dynamics of the rupture events to unmask the presence of the multiple β-peptides within the interaction area. To provide insight into these observations, we formulated a simple mechanical model of the interaction of the AFM tip with the immobilized β-peptides and used the model to demonstrate that adhesion measurements performed using short tethers (but not long tethers) are dominated by the interaction of single β-peptides because (i) the mechanical properties of the short tether are highly nonlinear, thus causing one β-peptide to dominate the adhesion force at the point of rupture, and (ii) the AFM cantilever is mechanically unstable following the rupture of the adhesive interaction with a single β-peptide. Overall, our study reveals that short tethers offer the basis of an approach that facilitates measurement of adhesive interactions with single molecules presented at surfaces.

Phase Transfer and Surface Functionalization of Hydrophobic Nanoparticle using Amphiphilic Poly(amino acid).

Functionalization of nanoparticles with chemical and biochemical is essential for their biomedical and other application. However, most of the high quality nanoparticles are hydrophobic in nature due to surfactant capping and their conversion into water-soluble functional nanoparticle via appropriate coating and conjugation chemistry is extremely critical issue. Here we report amphiphilic poly(amino acid)-based one-pot coating and conjugation approach that can transform hydrophobic nanoparticle into water-soluble nanoparticle functionalized with primary amine, thiol, and biomolecule. We have designed amphiphilic polyaspartimide that can anchor hydrophobic nanoparticle through octadecyl groups, leaving the polar polyethylene glycol and aspartimide groups exposed outwards. The aspartimide group is then reacted with primary amine containing chemical/biomolecule with the formation of water-soluble functional nanoparticle. This approach has been extended to different hydrophobic nanoparticles and biomolecules. The present approach has advantages over existing approaches as coating and functionalization can be performed in one pot and functional nanoparticles have <12 nm hydrodynamic size, high colloidal stability, and biocompartibility. This developed approach can be used to derive biocompatible nanobioconjugates for various biomedical applications.

Combining molecular dynamics and lattice Boltzmann simulations: a hierarchical computational protocol for microfluidics

A hierarchical computational protocol is introduced to investigate the role of interfacial and wetting properties to the fluid displacement in hydrophilic pore network models (PNMs). Based on the combination of molecular dynamics (MD) and lattice Boltzmann method (LBM) simulations at both nano- and microscales, we study the role of dispersed functionalized \(\hbox {SiO}_{2}\) nanoparticles (NP) in brine to the oil displacement process in a clay (montmorillonite—MMT) pore structure. Our MD calculations indicate that dispersion of NP, with different hydrophilic properties, in brine solution reduces the interfacial tension between oil and brine, followed by an increase in the contact angle. The lowest interfacial tension and highest contact angle are for the hydrophilic NP functionalized with polyethylene glycol groups. By mapping the properties obtained from MD into LBM simulation parameters, we explore the oil displacement process in hydrophilic PNMs at the microscale. For all systems, the Young–Laplace filling rules are obeyed and, due to the finger formation, the displacement efficiency decreases as the capillary number increases. It was observed that, with the inclusion of NP, a reduction in interfacial tension associated with an increase in the contact angle may enhance the oil displacement process in hydrophilic pore systems at the microscale. The proposed computational protocol can be a versatile tool to explore the potentialities of chemical additives, such as NP, for the oil recovery process and investigate the effects of interfacial tension and wetting properties on the fluid behavior at both nano- and microscales.

Propylene glycol alginate (PGA) gelled foams: A systematic study of surface activity and gelling properties as a function of degree of esterification

A series of propylene glycol alginates (PGA) with degrees of esterification (D.E.) in the range of 32–93% were investigated with respect to surface activity and gelling potential. The surface tension measurements revealed increasing surface activity with increasing contents of propylene glycol groups. The rheological characterization of the PGA series calcium gels uncovered that the gelling potential of the PGAs was surprisingly well conserved even at intermediate degrees of esterification, assumed to reflect heterogeneity in the esterification pattern. For the PGAs of highest degree of esterification the assumed electrostatic point associations combined with hydrogen bonding lead to the rapid formation of weak gels. The rheological properties of high D.E. PGA solutions could be easily modified through the addition of sodium chloride and urea. Self-supporting, heterogeneous and stable PGA and PGA/unmodified alginate gelled foams were prepared applying the internal setting method and characterized with respect to mechanical properties and density. Increasing foamability and corresponding decrease in densities of the gelled foams and their mechanical strength was observed with increasing D.E..

"Inverse" thermoresponse: heat-induced double-helix formation of an ethynylhelicene oligomer with tri(ethylene glycol) termini.

An ethynylhelicene oligomer [(M)-d-4]-C12-TEG with six tri(ethylene glycol) (TEG) groups at the termini was synthesized, and double-helix formation was studied using CD, UV-Vis, vapor pressure osmometry, dynamic light scattering, and 1H NMR. [(M)-d-4]-C12-TEG reversibly changed its structure between a double helix and a random coil in response to heating and cooling in aromatic solvents, non-aromatic polar organic solvents, and aqueous solvent mixtures of acetone/water/triethylamine. Notably, [(M)-d-4]-C12-TEG in acetone/water/triethylamine (1/2/1) formed a double helix upon heating and disaggregated into random coils upon cooling. The double helix/random coil ratio sharply changed in response to temperature changes. This is an unprecedented "inverse" thermoresponse, which is opposite to the "ordinary" thermoresponse in molecular dimeric aggregate formation. This phenomenon was explained by the dehydration of the terminal TEG groups and the formation of condensed triethylamine domains upon heating.

Switchable Surface Wettability by Using Boronic Ester Chemistry.

Here, we report for the first time the use of a boronic ester as an efficient tool for reversible surface post-functionalization. The boronic ester bond allows surfaces to be reversibly switched from hydrophilic to hydrophobic. Based on the well-known boronic acid/glycol affinity, this strategy offers the opportunity to play with surface hydrophobic properties by adding various boronic acids onto substrates bearing glycol groups. The post-functionalization can then be reversed to regenerate the starting glycol surface. This pathway allows for the preparation of various switchable surfaces for a large range of applications in biosensors, liquid transportation, and separation membranes.

Enhancing Cellular Uptake and Doxorubicin Delivery of Mesoporous Silica Nanoparticles via Surface Functionalization: Effects of Serum

In this study, we demonstrate how functional groups on the surface of mesoporous silica nanoparticles (MSNPs) can influence the encapsulation and release of the anticancer drug doxorubicin, as well as cancer cell response in the absence or presence of serum proteins. To this end, we synthesized four differently functionalized MSNPs with amine, sulfonate, polyethylene glycol, or polyethylene imine functional surface groups, as well as one type of antibody-conjugated MSNP for specific cellular targeting, and we characterized these MSNPs regarding their physicochemical properties, colloidal stability in physiological media, and uptake and release of doxorubicin in vitro. Then, the MSNPs were investigated for their cytotoxic potential on cancer cells. Cationic MSNPs could not be loaded with doxorubicin and did therefore not show any cytotoxic and antiproliferative potential on osteosarcoma cells, although they were efficiently taken up into the cells in the presence or absence of serum. In contrast, substantial amounts of doxorubicin were loaded into negatively charged and unfunctionalized MSNPs. Especially, sulfonate-functionalized doxorubicin-loaded MSNPs were efficiently taken up into the cells in the presence of serum and showed an accelerated toxic and antiproliferative potential compared to unfunctionalized MSNPs, antibody-conjugated MSNPs, and even free doxorubicin. These findings stress the high importance of the surface charge as well as of the protein corona for designing and applying nanoparticles for targeted drug delivery.

Site-Specific PEGylation of Therapeutic Proteins.

The use of proteins as therapeutics has a long history and is becoming ever more common in modern medicine. While the number of protein-based drugs is growing every year, significant problems still remain with their use. Among these problems are rapid degradation and excretion from patients, thus requiring frequent dosing, which in turn increases the chances for an immunological response as well as increasing the cost of therapy. One of the main strategies to alleviate these problems is to link a polyethylene glycol (PEG) group to the protein of interest. This process, called PEGylation, has grown dramatically in recent years resulting in several approved drugs. Installing a single PEG chain at a defined site in a protein is challenging. Recently, there is has been considerable research into various methods for the site-specific PEGylation of proteins. This review seeks to summarize that work and provide background and context for how site-specific PEGylation is performed. After introducing the topic of site-specific PEGylation, recent developments using chemical methods are described. That is followed by a more extensive discussion of bioorthogonal reactions and enzymatic labeling.

N-Monosubstituted Methoxy-oligo(ethylene glycol) Carbamate Ester Prodrugs of Resveratrol.

Resveratrol is a natural polyphenol with many interesting biological activities. Its pharmacological exploitation in vivo is, however, hindered by its rapid elimination via phase II conjugative metabolism at the intestinal and, most importantly, hepatic levels. One approach to bypass this problem relies on prodrugs. We report here the synthesis, characterization, hydrolysis, and in vivo pharmacokinetic behavior of resveratrol prodrugs in which the OH groups are engaged in an N-monosubstituted carbamate ester linkage. As promoiety, methoxy-oligo(ethylene glycol) groups (m-OEG) (CH3–[OCH2CH2]n–) of defined chain length (n = 3, 4, 6) were used. These are expected to modulate the chemico-physical properties of the resulting derivatives, much like longer poly(ethylene glycol) (PEG) chains, while retaining a relatively low MW and, thus, a favorable drug loading capacity. Intragastric administration to rats resulted in the appearance in the bloodstream of the prodrug and of the products of its partial hydrolysis, confirming protection from first-pass metabolism during absorption.