Copolymers hydrophilic

Interpolyelectrolyte complexation between various charged (co)polymers or between charged double-hydrophilic copolymers and surfactants has been used as a tool to generate well-defined micellar structures, as will be discussed in more detail in Sect. 7.4. 

Similar IPEC-based aqueous micelles can be obtained from the mixing of a double-hydrophilic copolymer AB with a homopolymer C or a diblock copolymer AC or a diblock copolymer DC, provided that IPECs can form between the B and C blocks. This kind of electrostatic complex has also been referred to as block ionomer complexes, or BIC. 

Since the hydrophobicity of styrene- or alkyl methacrylate-based monolithic matrices is too high to make them useful for hydrophobic interaction chromatography, porous monoliths based on highly hydrophilic copolymers of acrylamide and methylenebisacrylamide were developed [70,135]. The hydrophobicity of the matrix required for the successful separations of proteins is controlled by the addition of butyl methacrylate to the polymerization mixture. The suitability of this rigid hydrophilic monolith for the separation of protein mixtures is demonstrated in Fig. 21, which shows the rapid separation of five proteins in less than 3 min using a steeply decreasing concentration gradient of ammonium sulfate. 

In the mid to late 1990s, Mimotopes was producing rigid injection molded polypropylene devices that were surface grafted with either a hydrophilic copolymer of methacrylic acid/dimethyl acrylamide or the relatively hydrophobic polystyrene.12 The polymer was then suitably deriva-tized to allow the incorporation of a linker system. In contrast to the various commercial resins available at the time, the Crown was a macroscopic, quantized solid phase. As shown in Fig. 2, the Crowns were typically fitted to a polypropylene stem, which in turn could be fitted into a... 

Read, M.L., Dash, P.R., Clark, A., Howard, K.A., Oupicky, D., Toncheva, V., Alpar, H.O., Schacht, E.H., Ulbrich, K. and Seymour, L.W. (2000) Physicochemical and biological characterization of an antisense oligonucleotide targeted against the bcl-2 mRNA complexed with cationic-hydrophilic copolymers. Eur. J. Pharm. Sci., 10, 169-177. 

The hydrophilic copolymers synthesized from acrylic monomers and 2-octy Icyanoacry I ate barrier dressings were successful in providing protection for excised rats that were treated and inoculated with bacteria. The particulate dressing was not successful in providing protection for excised rats because the dressing was porous due to the lack of a continuous film and high water content in excess of 70%. 

Homopolymers of methacryloyloxyethyl-type monomers containing 5-FU, thymine, or adenine were very stable toward acids and bases, while their hydrophilic copolymers were found to be degraded in aqueous solution under mild conditions to give the derivatives of purine and pyrimidines. The derivatives released from the copolymers were identified by UV spectroscopy as N-hy-droxyethyl derivatives of 5-FU, thymine, or adenine after isolation by preparative TLC. This means that the ester groups of the polymer side chains were hydrolyzed in aqueous solution. 

Nanogels Cross-linked hydrophilic copolymers, e.g., Pluronic-poly(ethylenimine) (PEI) and polyethylene oxide (PEO)-PEI Covalent conjugation of polymers 20,51,52... 

Figure 6.21 Orientation of a hyperpolarizable dye layer at the surface of a hydrophilic copolymer. ...

Kataoka et al. [57, 58] investigated the formation of polyion complexes (PIC) from a pair of oppositely charged polypeptide block copolymers, namely of anionic poly(ethylene oxide)-( foc -poly(a, P-aspartate) and cationic polyethylene oxide)- foc -poly([2-aminoalkyl]-a,P-aspartamide) (see structure in Fig. 14a), in an aqueous milieu. Mixing of the double-hydrophilic copolymers at an equimolar... 

U.S. 5,733,861, March BASF Corporation Hydrophilic copolymers for reducing the viscosity of... 

Hydrophilic copolymers that reduce the viscosity of detergent slurries are disclosed in U.S. Patent 5,733,861. Viscosity-reducing properties are illustrated using data obtained from a Brookfield viscometer, Spindle no. 4,20 r/min, at 25°C. The copolymer comprises an unsaturated hydrophilic monomer copolymerized with an oxyethylated monomer. 

U.S. 5880081 03/1999 Gopalkrishnan et al.l BASF Hydrophilic copolymer (unsaturated philic copolymer with an oxyalkylated monomer)... 

The release profiles were also fitted to Eq. (1) using a nonlinear regression program to obtain estimates of B, the erosion rate. R 2 in all cases was greater than 0.99 and hence the good fit of the release profile to Eq. (1). The optimized values of B obtained by nonlinear regression are listed in Table 18. The erosion rate ranged from 0.0037 cm/day for the most hydrophobic copolymer. P(FAD-SA) 80 20 to 0.028 cm/day for the most hydrophilic copolymer, P(FAD-SA) 10 90. However, the erosion rate was not linearly dependent on the hydrophili-city of the polymer, expressed as % of sebacic acid in the copolymer (Fig. 18). 

Lens hazing and protein deposition are common problems for wearers of soft contact lenses. Previous experiments with hydrophobic-hydrophilic copolymers exposed to plasma showed protein adsorption to be minimal at intermediate copolymer compositions. Adsorption of proteins from artificial tear solutions to a series of polymers and copolymers ranging in composition from 100% poly (methyl methacrylate) (PMMA) to 100% poly(2-hydroxyethyl methacrylate) (PH EM A) was measured. The total protein adsorption due to the three major proteins in tear fluid (lysozyme, albumin, and immunoglobulins) was at a minimum value at copolymer compositions containing 50% or less PH EM A. The elution of the adsorbed proteins from these polymers and copolymers with various solutions also was investigated to assess the binding mechanism. 

The accumulation of proteins on contact lenses has long been viewed as an undesirable event. In this study, the effect of polymer composition on both the total amount of protein on the materials, and on the specific proteins on each polymer composition was documented. The importance of these factors for biological response is not known, so this situation remains a fertile area for investigation. This study also demonstrated that a linear variation in material composition will not necessarily result in a linear variation in absorbed layer protein composition. The minima and maxima noted at intermediate copolymer compositions have strong implications for both understanding the mechanism of protein adsorption and for biological response. Investigation is underway to explore further protein interaction with hydrophobic-hydrophilic copolymer materials. 

Read ML, Dash P, Clark A, Howard KA, Oupicky D, Toncheva V, Alpar HO, Schacht EH, Ulbrich K, Seymour LW. Physicochemical and biological characterisation of an antisense oligonucleotide targeted against bcl-2 mRNA complexed with cationic-hydrophilic copolymers. Eur J Pharm Sci 2000 10 169-177. 

The second step entailed the preparation of a more hydrophilic copolymer, P2 (80/20 PEG/copolyester, by mole) following the same reaction scheme as that described above for PI. However, the polymerization charge consisted of PEG (120g), TMC (26.6 g, 0.888 mol), glycolide (3.34 g, 0.029 mol), and stannous octanoate (0.203 mmol as a 0.2 M solution in dry toluene). 

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