Polyethylene oxides

The USPNF 23 describes polyethylene oxide as a nonionic homopolymer of ethylene oxide, represented by the formula (CHiCHiOIk, where n represents the average number of oxyethylene groups. It may contain up to 3% of silicon dioxide. 

Polyethylene oxide can he used as a tablet binder at concentrations of 5-85%. The higher molecular weight grades provide delayed drug release via the hydrophilic matrix approach see Table I. 

Polyethylene oxide has been shown to be an excellent mucoadhesive polymer. Low levels of polyethylene oxide are effective thickeners, although alcohol is usually added to water-based formulations to provide improved viscosity stability see Table II. Polyethylene oxide films demonstrate good lubricity when wet. This property has been utilized in the development of coatings for medical devices. Polyethylene oxide can be radiation crosslinked in solution to produce a hydrogel that can be used in wound care applications. 

White to off-white, free-flowing powder. Slight ammoniacal odor. 

Measured for four molecular weight grades 28 mm tablets in 300 ml of water. 

Fares and co-workers [29] used pyrolysis to characterise degradation products of polyethylene oxide. Both C-O and C-C bond scission of polymer backbone occured upon pyrolytic heating whereas the evolution of small molecules such as diethyl ether and acetaldehyde resulted from controlled thermal degradation of the polymer. 

The authors wish to thank MOSTl and CIFI for the grant and facility support. 

Assemblage of novel release modules for the development of adaptable drug delivery systems, 7. Control. Release, 111 (1-2), 212-218,2006. 

Strusi, et al.. Module assemblage technology for floating systems In vitro flotation and in vivo gastro-retention, /. Control. Release, 129 (2), 88-92, 2008. 

Oliveira, et al.. Assembled modules technology for site-specific prolonged delivery of norfloxacin, Int. J. Pharm., 405 (1-2), 90-96,2011. 

Timmermans, and A.J. Moes, How well do floating dosage forms float , Int.. Pharm., 62 (2-3), 207-216,1990. 

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A large number of polymeric compounds have been investigated, but most modem propellants utilize prepolymers that ate hydroxy-functional polybutadienes (HTPB), carboxy-functional polybutadienes (CTPB), or a family of polyethylene oxides (PEGs) to form urethanes. Typical cure reactions... 

Another subclass of substituted amides that is of great commercial value is the ethoxylated amides. They can be synthesized from alkanolamides by chain extending with ethylene or propylene oxide or by ethoxylation directly from the primary amide (46—48). It was originally beheved that the stepwise addition of ethylene oxide (EO) would produce the monoethano1 amide and then the diethanolamide when sufficient ethylene oxide was added (49), but it has been discovered that only one hydrogen of the amide is substituted with ethylene oxide (50—53). As is typical of most ethylene oxide adducts, a wide distribution of polyethylene oxide chain length is seen as more EO is added. A catalyst is necessary to add ethylene oxide or propylene oxide to a primary or an ethoxylated amide or to ethoxylate a diethoxy alkanolamide synthesized from diethanolamine (54). 

An example of an ionically conductive polymer is polyethylene oxide containing LiC104, which is used as a solid phase electrolyte in batteries. 

Occasionally, water-soluble plastics are required. Poly(vinyl alcohol) is commonly the first to be considered but some cellulose ethers, polyethylene oxides, poly(vinyl pyrrolidone) and A-substituted polyamides are among many possible alternatives. 

Deep fluonnation using the La-Mar technique was carried out on polymers such as polyethylene and polypropylene [M], on polyethers [19, 20, 21], and on polyesters subsequently treated with sulfur Cetrafluoride [22] Deep fluorinations carried out under conditions producing limited fragmentation produced oligomeric perlluoropolyethers from powdered polyethylene oxide [23] Deep fluorinations earned out in the limited presence of molecular oxygen result in the conversion of... 

FIGURE 4.2 Polyethylene oxide, dextran, and protein calibration curves for TSK-GEL SW Columns. Column TSK-GEL SW, two 7.S mm x 60 cm columns in series. Sample , proteins Q, polyethylene oxides O, dextrans. Elution dextrans and polyethylene oxides distilled water proteins 0.3 A1 NaCI in 0.1 M phosphate buffer, ph 7. Flow rate 1.0 ml/min. Detection UV at 220 nm and Rl. 

TSK-GEL column Particle size (/tm) Average pore size (A) Polyethylene oxides/glycols Molecular weight of sample Dextrans Globular proteins ... 

Figure 4.19 demonstrates the effect of sample concentration on the separation of polyethylene oxide (PEO). At a concentration of 1.6 mg/ml of each... 

Figures 6.14-6.16 show the chromatograms of polystyrene, polyethylene glycol, and polyethylene oxide standards using dimethylformamide (DMF) as an eluent.

Figure 6.21 shows the calibration curves of the SB-800 HQ series using standard pullulan. Because a high molecular weight standard sample is not available, the calibration curves of 805 and 806 are partly estimates (dotted lines). The difference in the conformation between polyethylene oxide (PEO) and pullulan in the solvent causes a shift of the calibration curves of pullulan slightly higher than those of PEO. The OHpak SB-800HQ series is better suited for the analysis of hydrophilic samples than the Asahipak GS/GE series. 

Nonionic Polyethylene oxide Polyethylene glycol Polysaccharides Pullulans Dextrans Cellulosics Polyvinyl alcohol Polyacrylamide 0.1 M NaNOj... 

Calibration curves for the Ultrahydrogel column family using using polyethylene oxide standards and water as the mobile phase are shown in Fig. 11.12. 

FIGURE 12.7 SEC calibration curves for PL aquagel-OH columns (300 X 7.5 mm), eluent water at 1.0 ml/min, polyethylene oxide/glycol calibrants. 

Nonionic, hydrophilic Polyethylene oxide, polyethylene glycol Polyviny alcohol, hydroxyethyl cellulose, polyacrylamide Pure water 0.1-0.2 M salt/buffer, pH 7... 

COMPARISON OF FOUR COMMERCIAL LINEAR AQUEOUS SIZE EXCLUSION COLUMNS AND FOUR SETS OF COMMERCIAL POLYETHYLENE OXIDE (PEO) STANDARDS FOR AQUEOUS SIZE EXCLUSION CHROMATOGRAPHY OF POLYVINYLPYRROLIDONE AND PEO... 

The results in Table 17.8 indicate that for polyethylene oxide standards Shodex columns have better separation efficiency than the TSK GM-PW and... 

TABLE 17.8 Separation Efficiency of Four Linear Columns in Water and Water/Methanol for Polyethylene Oxide Standards... 

ACPA azobis(4-cyanopentanoic acid) AIBN azobis isobutyronitrile) BPO benzoyl peroxide DVB divinyl benzene, EGA 2-ethylcyano-acrylate HPC hydroxypropyl cellulose MMA methyl methacrylate PAAc polyacrylic acid PEI polyethyleneimine, PEO/PPO polyethylene oxide/polypyropylene oxide copolymer PVME polyvinylmethylether PVP polyvinylpyrrolidone K-30 DMSO dimethylsulfoxide PGA polyglutaraldehyde CMS chloromethylstyrene PMMA-g-OSA polymethylmethacrylate grafted oligostearic acid. 

The term poloxamer is widely used to describe a series of ABA block coploymers of polyethylene oxide and polypropylene oxide, extensively used in industry as antifoams, emulsifiers, wetting agents, rinse aids, and in numerous other applications [1-5]. Poloxamers are amphiphilic in character, being comprised of a central polypropylene oxide (PO) block, which is hydrophobic, sandwiched between two hydrophilic polyethylene oxide (EO) blocks as shown below ... 

Ethylene oxide is a highly active intermediate. It reacts with all compounds that have a labile hydrogen such as water, alcohols, organic acids, and amines. The epoxide ring opens, and a new compound with a hydroxyethyl group is produced. The addition of a hydroxyethyl group increases the water solubility of the resulting compound. Eurther reaction of ethylene oxide produces polyethylene oxide derivatives with increased water solubility. 

Such cells are still produced by Tadiran, and the safety aspects are said to be solved using an electrolyte mixture of polyethylene oxide-methylene oxide which polymerizes with the HF released by hot LiAsFft at 135 °C the electrolyte turns... 

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