Polyethylene glycol , interaction with

J. L. Cleland and T. W. Randolph, Mechanism of polyethylene glycol interactions with molten globule folding intermediate of bovine carbonic B. J. Biol. Chem. 267 3147-3153 (1992). 

Sakellariou, P. Hassan, H. Rowe, R.C. Plasticization and interactions of polyethylene glycol 6000 with hydroxy-propyl methylcellulose/polyvinyl alcohol blends. Int. J. Pharm. 1994, 102, 207-211. 

M Alden, J Tegenfeldt, ES Saers. Structures formed by interactions in solid dispersions of the system polyethylene glycol griseofulvin with charged and non-charged surfactants added. Int J Pharm 94 31-38, 1993. 

It was established that CDs labelled with TEMPO derivatives, Le. spin labelled CDs 32-34 undergo interaction with PEG 600 (PEG = polyethylene glycol) and with PPG 425 (PPG = polypropylene glycol) in concentrated aqueous solutions. The EPR spectra of 32-34 are changed when they are complexed with PEG or PPG. It was observed that the relationship between rotational correlation times (t) and solvent viscosity caimot be described by the Debye-Stokes-Einstein equation, this fact being due to self-aggregation of alkylene glycols in concentrated solutions. However the use of the fractional Debye-Stokes-Einstein equation, i.e. the relationship between relative x values and relative viscosity is in accordance with the experimental data [77]. 

Alternatively, using a polyethylene glycol stationary phase, aromatic hydrocarbons can also be retained and separated primarily by dipole-induced dipole interactions combined with some dispersive interactions. Molecules can exhibit multiple interactive properties. For example, phenyl ethanol possesses both a dipole as a result of the hydroxyl group and is polarizable due to the aromatic ring. Complex molecules such as biopolymers can contain many different interactive groups. 

For some nonionic, nonpolar polymers, such as polyethylene glycols, normal chromatograms can be obtained by using distilled water. Some more polar nonionic polymers exhibit abnormal peak shapes or minor peaks near the void volume when eluted with distilled water due to ionic interactions between the sample and the charged groups on the resin surface. To eliminate ionic interactions, a neutral salt, such as sodium nitrate or sodium sulfate, is added to the aqueous eluent. Generally, a salt concentration of 0.1-0.5 M is sufficient to overcome undesired ionic interactions. 

By solubilizing very viscous aqueous solutions of polyethylene glycol in AOT/iso-octane solutions, it has been observed that the polymer leads to a decrease in the intermi-cellar interactions and enhances the stability of very large droplets with R values ranging from 55 to 150. The largest reversed micelle may contain up to 200 polymer molecules [238],... 

Soft gelatin capsules are not an inexpensive dosage form, particularly when compared to direct compression tablets [3]. There is a more intimate contact between the shell and its liquid contents than exists with dry-filled hard gelatin capsules, which increases the possibility of interactions. For instance, chloral hydrate formulated with an oily vehicle exerts a proteolytic effect on the gelatin shell however, the effect is greatly reduced when the oily vehicle is replaced with polyethylene glycol [3]. 

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