Polyvinylpyrrolidones physical properties

Glass transitions of polyvinylpyrrolidones of different molecular weight may be used as identityJ Water depresses the glass transitions and effects the physical properties of polyvinylpyrrolidone, as demonstrated by Tan and ChallaJ ... 

Laser-source confocal Raman spectroscopy was used to analyze solid dispersions to evaluate the physical properties and determine the distribution of ibuprofen in extrudates of polyvinylpyrrolidone (PVP). As is shown in Figure 14, a shift in the Raman spectra occurs when the crystalline form of ibuprofen is compared to a solution or a PVP extrudate containing ibuprofen. For comparison purposes, ibuprofen was completely dissolved in dimeric... 

Some commercially available protein-inert polymers commonly used in microfluidic applications, all of which require permanent surface modification, are polyacrylamide, poly(N-hydroxyethylacrylamide), poly(NJl -di-methylacrylamide) (PDMA), polyvinylpyrrolidone (PVP), poly(vinyl alcohol) (PVA), hydroxyethylceUulose (HEC), and hydroxypropylmethylcellulose (HPMC). To permanently attach protein-resistant materials to the channel surface, high-energy sources, special chemistries, or even strong physical adsorption have been employed to introduce reactive functionalities. After activation, protein-resistant polymers can be anchored via UV-initiated free-radical polymerization. Polymeric materials usually do not have good solvent and heat resistance compared with inorganic materials, and hence it is necessary to take precautions during surface treatment to avoid serious damage to the microstructure or alteration of the physical properties of the bulk material. 

Chokshi et al. utiUzed a torque rheometer to study the physical and viscoelastic properties of binary mixtures of indomethacin and polymers considered for HME processing (Chokshi et al. 2005). Selected polymers were Eudragit EPO (EPO), polyvinylpyrrolidone/vinyl acetate copolymer (PVP-VA), polyvinylpyrrolidone K30 (PVPK30), and poloxamer 188 (PI 88). The zero rate viscosity (jjo) for binary mixtures of indomethacin and EPO, PVP-VA and PVPK30 were lower than the pure polymers, whereas rjo for indomethacin/P188 mixture was higher than the pure... 

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