Effect Of Water-soluble Polymers Research Articles

Concentration and separation of aqueous solutions of Cu2+, Ni2+, Fe3+ by dextran

AbstractThe effects of water‐soluble polymers on the concentration and separation of the aqueous solutions of the metal ions have been studied. The separation of metal ions can be possible by ultrafiltration‐complexation process. The effect of Dextran, which is a water‐soluble polymer, on the concentration and separation of metal ions (Cu2+, Ni2+, Fe3+) have been investigated by using EC‐PEG 4000 alloy membranes. The permeability of these membranes for metal ions has been rrecorded at constant pressure but different pH values. It has been notices that the highest water‐permeable membrane is also permeable towards Cu2+ and Ni2+, but has shown a considerable retention for Fe3+ as a result of the hydrolysis of Fe3+. The retentions of metallic ions and metallic‐ion‐Dextran couples have been determined at constant pressure but different pH and polymer concentration values. It has been shown that Fe3+/Ni2+ and Fe3+/Cu2+ couples can be separated by using Dextran. © 1995 John Wiley & Sons, Inc.

The effect of water-soluble polymers on drug-cyclodextrin complexation

In aqueous solutions water-soluble polymers were shown to increase the solubilising effect of cyclodextrins on drugs. For example, the solubilising effect of 2-hydroxypropyl-β-cyclodextrin (HPβCD) with molar substitution of 0.6 was improved by 6–57% (on average 27%) when 0.25% (w/v) carboxymethylcellulose was present in the solution and 12–129% (on average 49%) when 0.25% (w/v) polyvinylpyrrolidone (PVP) was present. Similar results were obtained with other cyclodextrins and other polymers. For PVP and 10% (w/v) HPβCD the PVP concentration for maximum solubilisation appeared to be between 0.05 to 0.25% (w/v). At this low concentration PVP had insignificant effect on the viscosity of the aqueous HPβCD solution. The polymers increased the stability constants of the drug-cyclodextrin complexes. Addition of PVP to the aqueous complexation medium resulted in an increased negative enthalpy change, together with an increased negative entropy change.

Effects of Organic Dispersants on the Dispersion, Packing, and Sintering of Alumina

The effects of water‐soluble polymers and benzoic acid derivatives on green and sintered Al203 compacts were studied for two types of alumina powder. The percent of theoretical density achieved by each Al203 sediment was dependent primarily on the concentration of water‐soluble polymeric dispersant rather than on the pH. Aromatic acids, such as 4‐hydroxy‐ and 4‐aminobenzoic acid, were also effective dispersants. The final density and grain size of sintered compacts depended on the green microstructure of the compacts and on differences in the concentration of trace elements in the two powders.

Effect of water-soluble polymers on rodlike and spherical micelles formed from 2-alkylmalonate salts

The aggregation behavior of mono- and bis(tetramethylammonium) salts of 2-alkylmalonic acids (1-8) has been studied in aqueous solutions in the absence and presence of 0.5% (w/v) of poly(ethylene oxide) (PEO) or poly(vinyl methyl ether) (PVME). The mono-NMe4 salt of 2-dodecylmalonic acid forms rodlike micelles in a specific concentration range as evidenced by visually observed viscoelasticity of the solution and by H-1 NMR line broadening. The viscoelastic properties disappear upon addition of PEO or PVME, indicating a transition from rodlike to spherical, polymer-bound micelles. Interestingly, the interaction between the spherical micelles and the polymers is not accompanied by a reduction of the critical micelle concentration (cmc). The di-NMe4 salt of 2-dodecylmalonic acid forms spherical rather than rodlike micelles. The spherical micelles bind to PEO and PVME, and this interaction does lead to a considerable reduction of the cmc. Polymer-micelle interaction is also revealed by an increase of the clouding temperature for PVME. The experimental results are discussed in terms of interheadgroup interactions and recent theories for polymer-micelle association.

Effect of Water Soluble Polymers on Spray Droplet Size

ABSTRACT THE effects of polymer type and concentration, nozzle orientation, nozzle core size, and liquid shear on the size distribution of spray droplets produced in a high speed airstream for mixtures of water, Triton X-100 surfactant, and polymer product were analyzed with a laser particle measurement system. The effect of polymer concentration on droplet size was found to be dependent on polymer type. Polyvinyl and polyacrylamide polymers were found to be more effective than linear alkyl epoxide or polymide copolymers in increasing volume median diameter and reducing the percentage of spray volume composed of small droplets subject to spray drift. Shearing the polymer spray mixtures by multiple passes through a gear pump reduced both liquid viscosity and the size of spray droplets produced by disc-core nozzles in a 190 km/h airstream

Interactions between sodium dodecyl sulfate and polycarboxylates and polyethers. Effect of Ca 2+ on these interactions

The effect of water-soluble polymers (two polycarboxylates, and six polyethers) on the CMC and micellar aggregation number N of aqueous sodium dodecyl sulfate (SDS) was investigated by means of electrical conductivity and time-resolved fluorescence probing. The effect of Ca 2+ on SDS solutions containing polycarboxylates and/or polyethers was also examined. The polycarboxylates decrease the CMC and increase N and appear to behave like classical 1-1 electrolytes such as NaCl or sodium propionate, but their effect on N and the CMC is smaller than for these electrolytes. The difference can be explained on the basis of the theory of counterion condensation in polyelectrolyte solutions. It was also observed that polycarboxylates increase the resistance of SDS micelles to Ca 2+ by binding these ions. The polyethers (polyoxyethylene, polyoxypropylene and Pluronics) decrease both the CMC and N as a result of a direct interaction with SDS micelles. The decrease of N upon addition of polyethers takes place in pure SDS solutions, as well as in solutions containing polycarboxylates with or without added Ca 2+.

免疫グロブリンの熱凝集に関する研究 ＩＩ ヒト免疫グロブリンＧのエフェクター活性に及ぼす水溶性高分子の添加効果

免疫グロブリンの熱凝集に関する研究 ＩＩ ヒト免疫グロブリンＧのエフェクター活性に及ぼす水溶性高分子の添加効果

Effects of water-soluble polymers on the crystalline conversion of prednisolone in oil-in-water type ointment bases.

The effects of methylcellulose (MC) and hydroxypropylcellulose (HPC) on oil-in-water (o/w) type ointment bases and the crystalline conversion from the anhydrous form of prednisolone (A-PD) to its hydrated form (C-PD) in such o/w type ointment bases were studied. The weight loss of the base, that is the volume of water released from the base, was measured in dry conditions and at a low temperature (5°C). The weight loss of the base without MC or HPC (No.1 base) was about 7% in 10d. On the other hand, the weight losses of the base containing MC (No.3 base), and that containing HPC (No.6 base) were about 1% and 4% under the same conditions, respectively. The yield value of each of the bases Nos.1, 3, and 6 was measured with a spreading meter. The yield value of No.1 base was smaller than that of the other bases for 24h after preparation at room temperature (25°C). The yield value of No.3 base became lower and that of No.6 base became slightly greater than that of 24 h for 7 d after preparation upon storage at room temperature and humidity (25°C). However, the yield value of No.1 base increased after 7 d. The crystalline conversion of A-PD in o/w type ointment base was measured by the use of an X-ray diffractometer. A-PD was entirely converted into C-PD in No.1 base in only 1 d at 5°C. On the other hand, when MC or HPC was incorporated in the base, the conversion of A-PD to C-PD was retarded. The periods required for complete crystalline conversion from A-PD to C-PD in the bases (Nos. 2-4) containing MC and the bases (Nos.5-7) containing HPC were about 20-30 d and 3-18 d, respectively. Furthermore, in vitro release of PD from No.1 base without MC and from No.2 base containing MC were studied for 24 h after preparation at 5°C. Since A-PD was entirely converted into C-PD after 24 h at 5°C, the amount of PD released from No.1 base was less than that of immediately after preparation, whereas the release pattern of PD from No.2 base was the same as that from the base immediately after preparation since crystalline conversion did not occur in No.2 base. In addition, the release of PD from No.4 base was studied for 10 d after preparation at 5°C. The amount of PD released from No.4 base after 10 d was the same as that of immediately after preparation, since crystalline conversion of PD did not occur in this base. Water-soluble polymers such as MC and HPC act as protective colloids, and so the structure of the emulsion in the ointment base is stabilized. The structure of the emulsion in the base including water-soluble polymer is stabilized even at low temperature where the o/w type emulsion structure normally deteriorates. It is suggested that water-soluble polymer is an effective additive to o/w type ointment bases.

Fluorescence polarization study on the increase of membrane fluidity of human erythrocyte ghosts induced by synthetic water-soluble polymers

The effect of water-soluble polymers on the membrane fluidity of human erythrocyte ghosts was investigated and was compared with that of concanavalin A by means of the fluorescence polarization technique. 8-Anilino-1-naphthalene sulfonic acid sodium salt and 1,6-diphenyl-1,3,5-hexatriene were used as probe molecules. The membrane fluidity was increased by the addition of polycations with concentrations of less than 2 · 10 −3 wt% 60 min after mixing. The fluidity changes were affected by the chemical structure (hydrophobicity, charge density, etc.) of polycations. Thus, the membrane fluidity increased markedly with increasing charge density on the chain backbone of polycations. On the other hand, nonionic polymers such as poly(ethylene glycol) and poly(N- vinyl-2- pyrrolidone ) changed the membrane fluidity in a biphasic manner. That is, the fluidity of human erythrocyte ghost was temporarily increased and then decrease. For example, 20 wt% of poly(ethylene glycol) gave a maximum fluidity 15 min after mixing with erythrocyte ghosts. A similar fluidity change was observed by adding concanavalin A. Such fluidity changes were not observed when lipid bilayer vesicles were used instead of cell membranes. These results suggested that the increase of membrane fluidity resulted from the intramembraneous aggregation of membrane-bound proteins which was induced by the added polymers. Cell agglutination was also induced by the addition of a large amount of polymers. This agglutination was considered to be due to the intermembraneous aggregation of membrane-bound proteins.

Effects of water-soluble polymers and electrolytes on permeability of heavy clay soils

A study has been made of the effects of water-soluble polymers on the filtration and chemical response of gypsum-bearing soils from the Hunger Steppe and takyr-like soils from the Karsha Steppe.

Effect of Water Soluble Polymers on Dissolution Enhancement of Ibuprofen Solid Dispersion Prepared by Fusion Method

The purpose of this study was to prepare and characterize solid dispersions of the NSAID Ibuprofen with PEG 6000, Poloxomer 188 and Poloxomer 407 with the intention of improving its dissolution properties. The solid dispersions were prepared by the fusion method. Evaluation of the properties of the dispersions was performed using dissolution studies. The results obtained showed that the rate of dissolution of Ibuprofen was considerably improved when formulated in solid dispersions with PEG 6000 and poloxomer 188. Solid dispersions with poloxomer 407 showed drug retarding capability which may trigger more research in the intension of exploiting this feature to prepare sustained release dosage form. Key words: Ibuprofen; polyethylene glycol; poloxomer; solid dispersion; fusion method; dissolution DOI: 10.3329/sjps.v3i1.6801S. J. Pharm. Sci. 3(1): 63-67

Effect of water-soluble polymers on nitrate reductase activity.

SEVERAL years ago Whitaker1 observed that the presence of small quantities of bovine serum albumin, β-lactoglobulin, and other proteins enhanced the activity of a cellulase preparation obtained from culture filtrates of Myrothecium verrucaria when insoluble substrates were used. Tracey2 found a similar effect in the stimulation by cow serum of chitin hydrolysis by chitinase. More recently, activation by polymers has been observed in homogeneous aqueous enzyme systems. The action of liver diaphorase has been reported3 to be enhanced by bovine serum albumin and polyvinylpyrrolidone while polysaccharides, particularly starch, have been shown4 to increase the activity of horse-radish peroxidase. These findings suggest that the in vitro enhancement of enzymic activity by non-catalytic polymeric materials may be a phenomenon of broad biological significance.