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Results for “ION EXCHANGE RESINS”

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PubMed1983

[Ion-exchange sorption of calcium and strontium from blood and its plasma].

The authors explored the statics of Ca2+ and Sr2+ sorption from a saline, imitating the salt (mineral) composition of the blood plasma, and from blood plasma. As the plasma concentration was raised, there was a consistent decrease in ion sorption of KU = 2 X 8 cationite characteristic for M2+ complex formation in solution. Conventional constants for formation of complex compounds and mole proportions (%) of free (M2+) and complex forms (MLx-) metals were calculated. The time course of calcium and strontium sorption on KU = 2 X 8 ion-exchange resin from saline and blood plasma was studied. It was discovered that sorption from saline proceeded according to the externally diffusion kinetics type, whereas sorption from plasma according to the mixed type of the ion-exchange kinetics. The kinetic ratios were calculated for the indicated versions of sorption experiments. The mechanisms of sorption found in model experiments were extrapolated to dog experiments with blood decalcination, which supported the adequacy of experimental hemosorption under consideration.

Animals↗

PubMed1991

Extraction of mercury from groundwater using immobilized algae.

Bio-Recovery Systems, Inc. conducted a project under the Emerging Technology portion of the United States Environmental Protection Agency's (EPAs) Superfund Innovative Technology Evaluation (SITE) Program to evaluate the ability of immobilized algae to adsorb mercury from contaminated groundwater in laboratory studies and pilot-scale field tests. Algal biomass was incorporated in a permeable polymeric matrix. The product, AlgaSORB, packed into adsorption columns, exhibited excellent flow characteristics, and functioned as a "biological" ion exchange resin. A sequence of eleven laboratory tests demonstrated the ability of this product to adsorb mercury from groundwater that contained high levels of total dissolved solids and hard water components. However, use of a single AlgaSORB preparation yielded nonrepeatable results with samples collected at different times of the year. The strategy of sequentially extracting the groundwater through two columns containing different preparations of AlgaSORB was developed and proved successful in laboratory and pilot-scale field tests. Field test results indicate that AlgaSORB could be economically competitive with ion exchange resins for removal of mercury, with the advantage that hardness and other dissolved solids do not appear to compete with heavy metals for binding capacity.

Absorption↗

PubMed1981

Properties of agarose-encapsulated adsorbents. I. Adsorption of digoxin from human serum.

The elimination of the cardioactive steroid, digoxin, from human serum by a range of adsorbent phases has been investigated. In the native state, the uncharged resins of the Amberlite XAD-type proved more effective than the ion-exchange resins, Dowex 1X, or active charcoal. Of the materials tested, Amberlite XAD-8 is by far the best suited resin for haemoperfusion in cases of digoxin overdose, whereby the less efficient XAD-4 is more commonly employed at present in clinics. In order to improve the haemocompatibility of the adsorbent materials, the technique of encapsulation into large agarose beads has been employed. In contrast to the effects observed with many other classes of xenobiotics, encapsulation into agarose beads results in a considerable loss of adsorptive capacity of digoxin by Amberlite XAD-8. The poor performance of active charcoal in form of granules can be improved by an order-of-magnitude using charcoal powder encapsulated in agarose. Thus, the latter material, or uncoated XAD-8 resin should be considered as a better alternative to materials in current use for extracorporeal detoxification in cases of digoxin overdose.

Anion Exchange Resins↗

PubMed1979

The removal of hypnotic drugs from human serum. A comparative investigation of the adsorptive properties of native and agarose-encapsulated resins and charcoal.

The adsorptive capacities of some ion-exchange resins and activated charcoal towards the hypnotic drugs, phenobarbital, glutethimide, carbromal, and methaqualone, have been investigated. Furthermore, the properties of some of these resins and charcoal, encapsulated in an agarose matrix in the form of beads, have been compared with those of the adsorbent phases in their native states. In general, the adsorptive capacities of charcoal were at least as good as, and frequently better than those of the resins. Amberlite XAD-type resins had a higher affinity than Dowex-type resins for all the drugs tested, except for phenobarbital, which was not adsorbed to a satisfactory extent onto Amberlite XAD-4. The encapsulation of adsorbent phases into agarose beads of diameter 5-10 mm results in a reduction of the adsorbtion of the drugs. Nonetheless, the remaining adsorptive capacity is sufficient for application in an extracorporeal detoxification system. Moreover, the overwhelming advantage of good haemocompatibility is provided by the agarose-encapsulated adsorbents.

Adsorption↗

PubMed1982

Randomized controlled trial of colestipol in antibiotic-associated colitis.

Thirty-eight patients with severe antibiotic-associated postoperative diarrhoea were entered into a randomized controlled trial to compare colestipol (an ion exchange resin) in 17 patients with placebo (sherbet) in 21 patients. Clostridium difficile or its toxin was present before treatment in 12 of the colestipol group, compared with only 5 in the placebo group. Because of the low incidence of Cl. difficile or its toxin, the placebo group data from 22 patients receiving placebo in a previous trial (9 of whom had Cl. difficile or toxin) were included for comparison. Neither colestipol nor placebo had any influence on the faecal excretion of Cl. difficile or its toxin. Colestipol was clinically no better than placebo. In view of the persistent faecal excretion of Cl. difficile toxin, ion exchange resins cannot be recommended for the treatment of antibiotic-associated colitis.

Anti-Bacterial Agents↗

PubMed2003

Studies on the electrochemical and permeation characteristics of asymmetric charged porous membranes.

Asymmetric charged porous membranes were prepared by imbedding 10% (W/W) ion-exchange resin in cellulose acetate binder. Membrane potential and conductance measurements have been carried out in sodium chloride solutions at different concentrations to investigate the relationship between concentration of fixed charges and electrochemical properties of developed nonselective cation- and anion-exchange membranes. Counterion transport number and permselectivity of these membranes were found to vary due to the presence of ion-exchange resin. The hydrodynamic and electroosmotic permeability of sodium chloride solutions has been studied in order to compute equivalent pore radius. For cation- and anion-exchange membranes good agreement was observed between pore radius values estimated from hydrodynamic and electroosmotic permeability coefficient separately, while for nonselective membranes no correlation was found. Membrane conductance data, along with values of concentration of fixed charges, were used for the estimation of the tortuosity factor, salt permeability coefficient, and frictional coefficient between solute and membrane matrix employing an interpretation by nonequilibrium thermodynamic principles based on frictional forces. Moreover, surface morphological studies of these membranes also have been carried out and the membranes were found to be reasonably homogeneous.

Journal Article↗

PubMed1991

Partial degradation and biological activities of an antitumor polysaccharide from rice bran.

A rice bran polysaccharide designated RON was subjected either to partial hydrolysis with formic acid or to partial degradation by ultrasonic irradiation. A significant change in the molecular size was also observed during simple chromatography of RON on a strongly acidic ion exchange resin, although the apparent molecular weight of RON had been assumed to be more than 1 x 10(6) daltons (Da). This fact indicates that RON exists as molecular aggregates, presumably mediated by metal cations. Degradation products with average molecular weights above ca. 1 x 10(4) Da which were obtained by any of the three methods still retained the following activities of RON: in vivo antitumor activity against Meth-A fibrosarcoma in mice by oral administration, and in vitro macrophage stimulatory effects to induce tumoricidal activity and interleukin 1 production. This molecular size was proven to be the minimum requisite for these activities because smaller fragments were scarcely active. The aggregation was characteristic of RON but not essential for its antitumor activity because definite, though slightly reduced, activity was exhibited even by the smaller fragments obtained after the ion exchange resin treatment.

Animals↗

PubMed1998

Effectiveness of ciprofloxacin-polystyrene sulfonate (PSS), ciprofloxacin and ofloxacin in a Staphylococcus keratitis model.

PURPOSE: Staphylococcus aureus causes severe corneal infections that often result in corneal scarring and blindness. Presently, therapy often involves the use of a fluoroquinolone antibiotic. This study, employing an experimental rabbit model of Staphylococcus keratitis, compared the effectiveness of two commonly prescribed formulations of fluoroquinolones to an experimental formulation, ciprofloxacin with polystyrene sulfonate (ciprofloxacin-PSS). The ciprofloxacin-PSS formulation uses an ion exchange resin to aid in the delivery of drug to the cornea. METHODS: Early (4-9 h postinfection, PI) and late (10-15 h PI) therapies were studied, employing 5 groups: ciprofloxacin-PSS, ciprofloxacin, ofloxacin, PSS vehicle. and untreated. Dosing regimens were: every 30 min, 60 min, or a single drop applied at 9 h PI. Eyes were observed by slit lamp examination (SLE) and bacterial colony forming units (CFU) per cornea were determined. RESULTS: Early phase therapy with ciprofloxacin-PSS, ciprofloxacin, or ofloxacin administered every 30 or 60 min were equally effective (P > or = 0.2880), decreasing CFU per cornea by >5 log. Ciprofloxacin was significantly more active than ciprofloxacin-PSS or ofloxacin (P < or = 0.0410) when applied as a single drop. Late therapy with ciprofloxacin-PSS, ciprofloxacin, or ofloxacin administered every 30 or 60 min resulted in >3 log decrease in CFU per cornea relative to controls (P < or = 0.0001). CONCLUSIONS: Topical treatment of experimental Staphylococcus keratitis with ciprofloxacin-PSS, ciprofloxacin, or ofloxacin was effective. The effectiveness of ciprofloxacin-PSS suggests that improved drug delivery systems employing an ion exchange resin could be useful in an ocular fluoroquinolone formulation.

Animals↗

PubMedDate not supplied

Feasibility study on the utilization of rubber latex effluent for producing bacterial biopolymers.

Rubber latex effluent is a polluting source that has a high biochemical oxygen demand (BOD). It is estimated that about 100 million liters of effluent are discharged daily from rubber processing factories. Utilization of this effluent such as the use of a coupled system not only can reduce the cost of treatment but also yield a fermentation feedstock for the production of bioplastic. This study initially was carried out to increase the production of organic acids by anaerobic treatment of rubber latex effluent. It was found that through anaerobic treatment the concentration of organic acids did not increase. Consequently, separation of organic acids from rubber latex effluent by anion exchange resin was examined as a preliminary study of recovering acetic and propionic acids. However, the suspended solids (SS) content in the raw effluent was rather high which partially blocked the ion-exchange columns. Lime was used to remove the SS in the rubber latex effluent. After the lime precipitation process, organic acids were found to adsorb strongly onto the anion exchange resin. Less adsorption of organic acids onto the resin was observed before the lime precipitation. This was probably due to more sites being occupied by colloidal particles on the resin thus inhibiting the adsorption of organic acids. The initial concentration of organic acids in the raw effluent was 3.9 g/L. After ion exchange, the concentration of the organic acids increased to 27 g/L, which could be utilized for production of polyhydroxyalkanoates (PHA). For PHA accumulation stage, concentrated rubber latex effluent obtained from ion exchange resins and synthetic acetic acid were used as the carbon source. Quantitative analyses from fed batch culture via HPLC showed that the accumulation of PHA in Alcaligenes eutrophus was maximum with a concentration of 1.182 g/L when cultivated on synthetic acetic acid, corresponding to a yield of 87% based on its cell dry weight. The dry cell weight increased from 0.71 to 1.67 g/L. On the other hand, using concentrated rubber latex effluent containing acetic and propionic acids resulted in reduced PHA content by dry weight (14%) but the dry cell weight increased from 0.49 to 1.30 g/L. The results clearly indicated that the cells grow well in rubber latex effluent but no PHA was accumulated. This could be due to the high concentration of propionic acid in culture broth or other factors such as heavy metals. Thus further work is required before rubber latex effluent can be utilized as a substrate for PHA production industrially.

Anaerobiosis↗

PubMed1977

Continuous direct measurement of intracellular chloride and pH in frog skeletal muscle.

1. Ion-sensitive electrodes (made with a chloride-sensitive ion-exchange resin) were used to measure the internal chloride activity (a(i) (Cl)) of frog sartorius fibres at 25 degrees C.2. The internal pH (pH(i)) of other sartorius fibres was measured with a recessed tip pH-sensitive electrode (made with pH-sensitive glass).3. In normal bicarbonate-free solution (containing 2.5 mM potassium), the average chloride equilibrium potential, E(Cl) (calculated from a(i) (Cl) and the measured chloride activity of the external solution (a(o) (Cl)) was 87.7 +/- 1.7 mV (mean +/- S.E.; n = 16) in fibres where the average membrane potential, E(m), was 88.3 +/- 1.5 mV (mean +/- S.E.; n = 16). In experiments where a(i) (Cl) was varied between about 1 and 10 mM (which corresponds to values of E(m) between about -105 and -50 mV) E(Cl) was within 1-3 mV of E(m) at equilibrium. These measurements of a(i) (Cl) were obtained from the potential difference between the chloride-sensitive electrode and an intracellular indifferent micro-electrode filled with potassium chloride. If a potassium sulphate-filled indifferent micro-electrode was used, then values of a(i) (Cl) below about 5 mM were erroneously high, probably due to interference from other sarcoplasmic ions at the indifferent electrode.4. In solutions containing 15 mM bicarbonate and gassed with 5% CO(2), pH(i) was 6.9, corresponding to an internal bicarbonate concentration of 7.6 mM. E(Cl) measured in this solution was some 4 mV positive to E(m). Most of the difference between E(Cl) and E(m) could be ascribed to interference by sarcoplasmic bicarbonate on the basis of selectivity measurements of chloride against bicarbonate made on the ion-exchange resin in the relevant range of a(Cl).5. If bicarbonate/CO(2) in the external solution was replaced by HEPES/pure O(2) at constant pH, then pH(i) rose from 6.88 +/- 0.02 (mean +/- S.E.) to 7.05 +/- 0.02. A change in external pH of 1 unit caused pH(i) to change by about 0.02 unit and the intracellular buffering power was calculated to be about 35.6. In solution made hypertonic by the addition of sucrose, E(m) changed little or depolarized and E(Cl) and E(m) remained close. In contrast, in solution made hypertonic by the addition of solid sodium chloride (high-chloride solution) E(Cl) became negative to E(m). Conversely in low chloride solution E(Cl) became positive to E(m).7. When the chloride permeability (P(Cl)) was reduced by the use of acid solution, E(Cl) moved positive to E(m) indicating an accumulation of internal chloride. When P(Cl) was increased again by returning to more alkaline solution, E(m) depolarized to E(Cl).8. The results are consistent with the existence of a small, active movement of chloride, the effects of which are normally obscured by large passive movements of chloride when P(Cl) is large.

Animals↗

PubMed2004

The retention of some open-chain diamines on a strong cation-exchange resin in ion chromatography as a function of their structure.

This work reports the results of a study of the influence of the structure of some open-chain diamines on their retention in high-performance ion chromatography (HPIC). We examine a set of eight diamines, in which the N atoms are separated by two C atoms and are differently N- and C-alkyl substituted; four of these diamines have the same formula weight. In the other two sets, the diamines are different from each other, either in terms of the length of the alkyl chain between the N atoms or in terms of the length of the substituent(s) on the nitrogen atom(s). The mobile phase is a mixture of HClO4 0.100 mol/L, 0.160 < C(NaClO4) < 1.50 mol/L, and 0 < acetonitrile% < or = 15 (v/v). The amines are detected by integrated amperometry. Interpretation of experimental data shows that (a) elution occurs for both ionic and hydrophobic interactions and is dependent on all the components of the mobile phase, (b) the diamines are eluted in any case as dications, and (c) steric hindrance significantly influences elution times. Some examples of separation are proposed.

Journal Article↗

PubMed1960