Preparation and characterization of macroporous monoliths imprinted with erythromycin.

The synthesis of macroporous molecularly imprinted monoliths was performed using the monomers system 2-hydroxyethyl methacrylate-ethylene glycol dimethacrylate and erythromycin as a template. The copolymerization was carried out in situ inside 50 mm × 4.6 mm i.d. stainless-steel tubing. The morphology of the monoliths was examined with scanning electron microscopy. The porous characteristics were determined both from the data of hydrodynamic permeability of monoliths and by means of mercury intrusion porosimetry. The retention parameters of target substance (erythromycin), values of calculated imprinting factors and apparent dynamic dissociation constants were obtained for monoliths prepared with the application of different amount of template (4, 8 and 12 mol%). The separations of the mixtures azithromycin/erythromycin and ciprofloxacin/erythromycin were demonstrated. Additionally, the possibility of erythromycin quantification in human blood plasma was shown.

[Molecularly imprinted hydrophilic polymer sorbents for selective sorption of erythromycin].

New hydrophilic polymer sorbents comprising reactionary sites which are complementary to a molecule of antibiotic erythromycin were synthesized by the method of molecular imprinting. A series of similar sorbents without reactionary sites was used for comparison of sorption characteristics. Sorption of erythromycin on both types of polymer sorbents synthesized was studied in a wide range of pH and ionic strength. Selectivity of erythromycin sorption on molecularly imprinted cross-linked polymers was shown to depend on the specific interaction of target molecule with polymer matrix. This type of sorbent is perspective for the development of antibiotic purification directly from a culture medium Saccharopolyspora erythreus.

[Sorption of lysine by molecularly imprinted carboxyl sorbents].

Tuned (molecularly imprinted) and nontuned, with respect to lysine amino acid, carboxylic heteroreticular sorbents based on methacrylic acid and ethylene glycol dimethacrylate, were synthesized. Study of sorption of lysine within wide pH range and ionic strength indicated significant dissimilarities in amino acid sorption by tuned sorbents, which were expressed as an increase in the contribution of nonionic interaction, and resulted in a decrease in the ionic strength effect on the sorption capacity, as well as an increase in amino acid sorption selectivity.

[Dependence of equilibrium and kinetic parameters of erythromycin: a sorption on the structural characteristics of the biosorbent].

The use of special synthetic sorbents with surface carboxyl groups allowed us to increase fourfold the effective diffusion coefficient for erythromycin. The maximum sorption capacity for the antibiotic exceeded twofold that observed in experiments with a macroporous sulfocation exchanger MN-500. The sorption of the antibiotic was completely reversible upon treatment with a combined eluant that competitively interacts with the sorbent and does not impair the structural characteristics of erythromycin.

Experimental and theoretical studies of sorption kinetics of the anthracycline antitumor antibiotic rubomycin on a carboxylic heterogeneous sorbent. Bidisperse model of sorption kinetics.

The present work is devoted to experimental and theoretical studies of the sorption kinetics of the anthracycline antitumor antibiotic rubomycin on a carboxylic heteroreticular sorbent, BDM-12. The dependence of sorption kinetic parameters on the radius of sorbent grains has been experimentally obtained. The comparison of experimental data with the predictions of both homogeneous and "shell-and-core" models demonstrates the impossibility of using these models for adequate description of the rubomycin sorption kinetics on the sorbent, BDM-12. We have proposed a theory using the bidisperse model of heterogeneous sorbent grain and "linear driving force" approximation. This approximation can be applied at 10(-3) < alpha = tauI/tauA < 1, x < 1 and gives the values of the degree of process completion with relative errors approximately (alpha x)2. Here tauI and tauA are the characteristic times required for diffusion penetration into the macro- and microspheres, respectively, x is the ratio of the microsphere and macrosphere uptakes at equilibrium. The dependences of two characteristic times of the sorption process (for short- and long-time regions) on the radius of a sorbent grain have been derived. The predictions of the theory developed here are in good agreement with our experimental data and make it possible to calculate the kinetic parameters tauI, tauA and x.

Optimization of experimental conditions for the preparative displacement chromatography of antitumor anthracycline antibiotics on carboxylic sorbents.

The physico-chemical conditions and the limits of the rates of mobile phases are determined when effective regimes of preparative chromatography in the conditions of sharpening the boundaries of chromatographic zones of anthracycline antibiotics are realized. The influence of pH on the equilibrium, kinetics and dynamics of sorption of anthracycline antibiotics (rubomycin, doxorubicin and carminomycin) on the carboxylic sorbents has been studied.

[Optimization of conditions of preparative chromatography of carminomycin on a carboxylic cation exchanger]. / Optimizatsiia uslovii preparativnoi khromatografii karminomitsina na karboksil'nom kationite.

Time course of equilibrium and nonequilibrium sorption of carminomycin on carboxylic cation exchanger BDM-12 has been studied. Physicochemical requirements and limits of mobile phase flow rate are determined for the regular mode of preparative chromatography under the conditions of sharpening of the chromatographic zone.

[Frontal displacement chromatography of melittin on meshed polymer ionites]. / Frontal'no-vytesnitel'naia khromatografiia melittina na setchatykh polimernykh ionitakh.

Conditions of frontal displacement chromatography were optimized for preparative purification of the polypeptide hormone melittin from bee venom. Melittin was purified to an extent higher than that of a standard preparation described in the biochemical literature.

[Effect of the kinetic selectivity of eremomycin adsorption on the concentration of components in chromatographic bands]. / Vliianie kineticheskoi selektivnosti sorbtsii eremomitsina na kontsentrirovanie komponentov v khromatograficheskikh zonakh.

The adsorption dynamics of antibiotic eremomycin to structurally segregated carboxylic adsorbents was studied. It was shown that effects of the kinetic selectivity of adsorption lead to an additional narrowing of bands containing the component to be separated. This narrowing provides the possibility of superpurification of biologically active compounds by the "small shift" method of quasiequilibrium chromatography.

[New principles of ion exchange preparative chromatography and their applications for isolation, purification and super purification of antibiotics]. / Novye printsipy ionoobmennoi preparativnoi khromatografii i ikh primenenie dlia vydeleniia, ochistki i superochistki antibiotikov.

New types of structurally segregated heteronetwork biosorbents with given parameters of heterogeneity and porosity have been developed. Physico-chemical characteristics of the biosorbents on the basis of which one can predict optimal structures of ion exchangers to be used in preparative chromatography of biologically active compounds were studied. A new principle of sequential displacement of ions of organic compounds, in particular antibiotics, adsorbed on selective biosorbents with a high adsorption capacity was developed, which enables purification and superpurification of the desired compound. The method is based on the effect of small thermodynamic shifts in physico-chemical parameters of the elution system, which results in preparative separation of substances with close properties and in purification of the desired compound from microadmixtures. The "small shift effect" is realized in the case of limiting thermodynamic and kinetic parameters of heterogeneous mass exchange and with biosorbents possessing a highly selective adsoprtion capacity.