Lithium-ion coordination-induced conformational change of PEG chains in ionic-liquid-based electrolytes.

Transesterification catalyst for aliphatic oligocarbonates

Poly(ethylene glycol) is a polymer that is widely used as a biomaterial and has been approved in a host of applications. While generally viewed as inert, recent studies with poly(ethylene glycol) suggest that it may have some effects on cells and tissues, making it potentially attractive as a therapeutic agent. In this study, the effect of poly(ethylene glycol) on the cell viability, membrane transport and apoptotic markers of metastatic melanoma cells was examined. The data were combined with observed effects of the polymer on the cell media, including osmolality and viscosity, in order to elucidate any structure-function relationship between the polymer and cells. It was observed that poly(ethylene glycol) reduced the cellular viability of A375 cells, and that the effect was dependent on poly(ethylene glycol) molecular weight and concentration. The mechanism was highly correlated with changes in the osmolality of the cell medium, which is determined by the inherent structure of poly(ethylene glycol), and in particular the ethylene oxide units. This mechanism was specific to poly(ethylene glycol) and was not observed with the similar linear, hydrophilic polymer poly(vinyl pyrrolidone). Overall, the data suggest that poly(ethylene glycol) and poly(ethylene glycol)-like compounds have a distinct effect on cellular activity, presumably mediated in part by their osmotic effects, supporting the further investigation of these polymers as pharmaceutically active compounds.

Mucosal barriers are a natural defense system for preventing the entry of foreign objects into the body; however, they pose obstacles for effective drug delivery. Coated polymer nanoparticles (NPs) have been shown to possess improved rates of diffusion across mucus compared to their uncoated, or bare, counterparts. Choline carboxylic acid-based ionic liquids (ILs) are highly tunable and show high biocompatibility and mucus modulation properties, making them an ideal choice for the improvement of NP diffusion through mucosal barriers. This study aimed to investigate whether the use of choline-based ILs has a positive effect on the dispersibility of poly(lactic-co-glycolic acid) (PLGA), poly(ethylene glycol) methyl ether-block-poly(lactide-co-glycolide) (PEG-PLGA), and poly(ethylene glycol)-poly(lactic acid) (PEG-PLA) NPs through nasal mucus by using a multiple particle tracking method. The samples, according to the IL used, showed altered rates of diffusion in both aqueous and mucosal environments. The use of CA2HE 1:1 with PEG-PLGA NPs slowed NP diffusion, while the use of the same IL increased diffusion for PEG-PLA. Additionally, UV-vis spectroscopy was used to identify the possible formation of complexes between the mucin polymer and NPs. Circular dichroism (CD) spectroscopy was used to analyze any potential changes in the secondary structure of mucin as a result of the introduction of polymeric NPs. It was demonstrated that the use of an IL can stabilize the interactions between polymer NPs and mucin polymers. Isothermal titration calorimetry was used to obtain quantitative measurement of the binding energies between NPs and mucus and serves to confirm the results obtained from CD spectroscopy. Last, an ex vivo porcine nasal mucosa model was used to explore their use in a nasal delivery context, disclosing a possible connection between the use of zwitterionic transport materials and more effective drug delivery. This research demonstrates the potential of choline carboxylic acid-based ILs to control the transport behavior of polymer NPs for intranasal drug delivery.

Aggregation and fusion of unilamellar vesicles by poly(ethylene glycol)

Background Reducing ocular surface toxicity induced by topical antiglaucoma medications,and thus improving the therapeutic compliance of glaucomatous patients to treating drug become an urgent issue in the long-term antiglaucomatous therapies.Whether polyethylene glycol,a new type of artificial tear,can play a protective role from ocular surface toxicity induced by topical antiglaucoma medications remains further study.Objective The present study was to investigate the protective effect of polyethylene glycol on ocular surface toxicity induced by prolonged use of benzalkonium chloride-preserved latanoprost eye drops.Methods Thirty adult female New Zealand rabbits were randomly divided into normal control group,phosphate buffer solution (PBS) group and polyethylene glycol eye drops group.PBS with 0.005％ latanoprost was topically administered for consequent 60 days in the PBS group,and 0.005％ latanoprost with polyethylene glycol eye drops was used at the same way in the polyethylene glycol group.Schirmer Ⅰ test,fluorescein and rose bengal staining of cornea and conjunctiva,conjunctiva impression cytology specimens collecting were performed before experiment as well as 31 and 61 days after administration of drug.Histomorphological and ultrastructural changes of cornea and conjunctiva were observed under the light microscopy,scanning and transmission electron microscopy on day 61.Results The score of corneal fluorescine staining was significantly different among the control group,PBS group and polyethylene glycol group (H =25.265,P＜0.001 ;H=29.426,P＜0.001) on day 31 and day 61.Significant difference also was found in the score of rose bengal staining of cornea and conjunctiva (H=26.167,P＜0.001 ;H =29.212,P＜0.001),Schirmer Ⅰ test value (F=4.746,P＜0.05) and conjunctival goblet cell density (F=18.055,P＜0.001).Compared with the control group,corneal fluorescein scores [0(0,1.0) vs.3 (2.0,3.0)] and rose bengal scores [0(0,1) vs.2(2,3)] were significantly increased (both P＜0.001),and Schirmer Ⅰ test value scores and conjunctival goblet cell density were decreased ((5.18±0.46/)mm vs.(9.43±0.57)mm;(53.04±2.98)/HP vs.(87.73±2.34)/HP) (both P＜0.01)on day 61.Impaired microvilli and organelles of the corneal and conjunctival epithelial cells were observed.Compared with PBS-treated group,PEG-treated group showed decrease in fluorescein [3(2.0,3.0) vs.1 (0.5,1.0)] and rose bengal scores [2 (2,3) vs.1 (0,1)] (both P＜0.001),increase in Schirmer Ⅰ test value scores [(7.00±0.71)mm vs.(5.18±0.46) mm,P＜0.05],increase in goblet cell density ((63.88±3.32)/HP vs.(53.04±2.98)/HP,P＜0.05) and improvement of grading scores of conjunctival epithelium on day 61.In addition,complete mierovilli and cell organelles were found in the corneal and conjunctival epithelial cells in the polyethylene glycol group.Conclusions Topical application of polyethylene glycol can decrease the ocular surface toxicity induced by benzalkonium chloride-preserved latanoprost. Key words: Polyethylene glycol; Latanoprost; Benzalkonium chloride; Ocular surface toxicity

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Poly(ethylene glycol) (PEG) is one of the most useful protein salting-out agents. In this study, it has been shown that the salting-out effectiveness of PEG can be explained by the large unfavorable free energy of its interaction with proteins. Preferential interaction measurements of beta-lactoglobulin with poly(ethylene glycols) with molecular weights between 200 and 1000 showed preferential hydration of the protein for those with Mr greater than or equal to 400, the degree of hydration increasing with the increase in poly(ethylene glycol) molecular weight. The preferential interaction parameter had a strong cosolvent concentration dependence, with poly(ethylene glycol) 1000 having the sharpest decrease with an increase in concentration. The preferential hydration extrapolated to zero cosolvent concentration increased almost linearly with increasing size of the additive, suggesting steric exclusion as the major factor responsible for the preferential hydration. The poly(ethylene glycol) concentration dependence of the preferential interactions could be explained in terms of the nonideality of poly(ethylene glycol) solutions. All the poly(ethylene glycols) studied, when used at levels of 10-30%, decreased the thermal stability of beta-lactoglobulin, suggesting that caution must be exercised in the use of this additive at extreme conditions such as high temperature.

Spectrophotometric assay for protease activity in ionic liquids using chromogenic substrates

Polyhedral oligomeric silsesquioxane (POSS) is an important building block for constructing organic-inorganic hybrid molecules or polymers. In this work, we report amphiphilic, incompletely condensed POSSs (IC-POSSs) possessing various substituents on the seven silicon atoms and two kinds of poly(ethylene glycol)s (PEGs) with different chain lengths. The IC-POSS cores possessed comparable thermal stability to that of the completely condensed POSS (CC-POSS) analogs, despite their open cage structure. The amphiphilic IC-POSSs formed micelles of different sizes and had polydispersity indices (PDIs) that were dependent on the substituents and the PEG chain length. Additionally, the lower critical solution temperatures (LCSTs) were observed for amphiphilic IC-POSSs possessing shorter PEG chains, while aqueous solutions of those with longer PEG chains showed high transmittance even at 80 °C. Amphiphilic incompletely condensed polyhedral oligomeric silsesquioxanes possessing various substituents and poly(ethylene glycol)s of different chain lengths have been developed. It has been elucidated that their self-association behaviors in water are dependent on the substituents and chain lengths of poly(ethylene glycol)s. Precise molecular design, excellent thermal stability, and good dispersibility have been realized at once.

ABSTRACTThis study used poly(butylene succinate) and poly(ethylene glycol) to modify poly(3-hydroxybutyrate-co-3-hydroxyvalerate). The results showed that the incorporation of poly(butylene succinate) and poly(ethylene glycol) improved the mechanical properties of blends. The results showed that crystallinity of the poly(ethylene glycol)-containing blends decreased, so do the crystallization temperature and melting temperature of the poly(3-hydroxybutyrate-co-3-hydroxyvalerate) component of blends. Poly(butylene succinate)/poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/poly(ethylene glycol) ratio of 50:20:30 was chosen owing to its good properties. The poly(3-hydroxybutyrate-co-3-hydroxyvalerate) component of blends can be degraded completely by Pseudomonas mendocina DS04-T, whereas this strain cannot degrade poly(butylene succinate) and poly(ethylene glycol). Apart from poly(butylene succinate), Fusarium sp. FS1301 can also biodegrade poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and poly(ethylene glycol).

Physicochemical properties and thermal-responsive phase separation of poly(ethylene glycol)-based ionic liquids

Viscosity prediction of polyethylene glycol–dextran–water solutions used in aqueous two-phase systems

Densities of one acidic ionic liquid (IL) Quinolinum hexafluorophosphate ([HBpy][PF 6 ]), and four neutral dicationic ionic liquids (ILs) based on quinoline and hexafluoro-phosphate and linked with poly(ethylene glycol) (PEG): ([PEG 200 -DIL][PF 6 ] 2 , [PEG 400 -DIL][PF 6 ] 2 , [PEG 800 -DIL][PF 6 ] 2 and [PEG 1000 -DIL][PF 6 ] 2 ) were determined. In addition, the solubilities of six ILs in six lower alcohols, water, acetonitrile and diethyl ether were measured at 288.15 K; and the hydroscopicity of above five ILs were measured at the temperature of 298.15 K and relative humidity of 79% for 24 h. Densities of five ionic liquids were determined between 283.15 and 333.15 K. Then the densities of five binary system (ILs/acetonitrile) were explored between 283.15 and 333.15 K, the type of the ionic liquid, the concentration of five ILs in CH 3 CN, and the effect of temperature on the binary systems, were correlated with the measured data.

Objective To assess the clinical effects of simethicone emulsion combined with polyethylene glycol on bowel preparation for colonoscopy. Methods Two hundred out-patients, who underwent colonoscopy, were randomly divided into the study group and the control group. The study group was given simethicone in addition with polyethylene glycol, and the control group was given polyethylene glycol only. The differences on bowel preparation scores, air bubble reduction rate, colon lens sharpness, ileocecal region arrival time, colon polyp detection rate, the number of colon poly detection, and adverse event rate between the two groups were compared. Results The air bubble reduction rate, colon lens sharpness score and ileocecal region arrival time of the study group was 1(0-3) score, 1.0(0-2) score, and 9 (5-21) min, respectively, which was 2 (1-3) score, 1.5 (0-2) score and 12 (6-22) min, respectively in the control group. Differences between the two groups were statistically significant(Z=-9.490, P=0.000; Z=-6.768, P=0.000; Z=-5.521, P=0.000). For the bowel preparation score, colonoscopy polyp detection rate, the detection rate of colon polyp of diameter less than 5 mm, and number of colonoscopy polyp detection, there was no statistical difference between the two groups (P>0.05). No adverse events were observed in the both two groups. Conclusion The bowel preparation using simethicone combined with polyethylene glycol could effectively decrease the number of air bubble, enhance colon lens sharpness and shorten operation time, which contributes significant improvement for colonoscopy quality. Key words: Colonoscopy; Bowel preparation; Simethicone; Polyethylene glycol

A novel kind of gel polymer electrolytes (GPE) based on comb-like copolymers of poly(ethylene glycol) monomethylether (mPEG) grafted carboxylated butadiene-acrylonitrile rubber (XNBR) were prepared by introducing ionic liquids and LiClO4 into polymer framework. FTIR spectra confirmed the grafting of mPEG to XNBR as side chains, and the content of grafted mPEG were calculated from the integral area of related peaks in 1 H NMR spectra. Such grafted copolymer based GPE with ionic liquids as solvent showed higher ionic conductivity and reached a maximum ionic conductivity of 1.64 × 10−3 S/cm (30 °C) in the experimental range, because the copolymers performed better polymer chain flexibility, which could be concluded from the decrease of Tg and crystallinity through DSC analysis. The generated GPE exhibited high electrochemical stability and the unit cell of LiFePO4/GPE/Li could be cycled at room temperature.