Interaction of richlocain with some linear and crosslinked polymers

The interaction of local anesthetic drug richlocain with linear polyacrylic acid and crosslinked sodium polyacrylate, linear and crosslinked acrylic acid-Schiff base copolymers has been investigated. The compositions of forming polymer-drug complexes were determined. The influence of external factors such as pH, ionic strength, temperature and thermodynamic quality of solvent on the stability of these complexes was studied. The kinetics and activation energy of drug release from the gel matrix has been evaluated.     

Synthesis and characterization of novel hydrophobically modified polybetaines as pour point depressants

A novel hydrophobic monomer was synthesized from the acetoacetic ester and dodecylamine by condensation reaction in mild conditions. The modification by the dodecyl groups monomer was involved in the Michael addition reaction with acrylic (or methacrylic) acid followed by radical polymerization. Both linear and crosslinked novel betaine‐type polyampholytes bearing hydrophobic “tail” and hydrophilic “head” were obtained. The linear polymer was characterized by viscometry, FTIR, and Raman spectroscopy. Swelling–shrinking behavior of linear and crosslinked samples was studied in water–DMF and water–DMSO mixtures. The applicability of hydrophobically modified polybetaines as pour point depressants (fluidity improvers) was also demonstrated. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1042–1048, 2004     

Complex formation of polymethacrylic acid with random copolymer of vinylpyrrolidone and vinylamine in solutions

Summary By IR-Spectroscopic, conductometric, potentiometric and viscometric methods the formation of interpolymer complexes in polymethacrylic acid-random copolymer of vinylpyrrolidone and vinylamine (VP/VAm, 88 mol.% of VP) systems in water and methanol have been shown. The properties of copolymer complexes (PMAA-VP/VAm) are compared with ones of homopolymer complexes of polymethacrylie acid-polyvinylpyrrolidone (PMAA-PVP).     

Interpolymer complexes of novel linear and crosslinked acrylic acid–Schiff base copolymers

Novel linear and crosslinked copolymers of acrylic acid and Schiff base, containing the amine groups in the main chain and the carboxylic groups in the side chain, have been synthesized by the Michael addition reaction followed by radical copolymerization. The copolymers that exhibited poly(ampholyte–electrolyte) behaviour were used to prepare complexes by reaction with anionic (poly(acrylic acid), poly(styrene sodium sulfonate)), cationic (polyethyleneimine, poly(hexamethylene guanidine)) and non‐ionic (poly(N‐vinylpyrrolidone), poly(ethylene glycol), poly(vinyl alcohol)) polymers. The influence of external factors, such as solvent quality, temperature, pH and ionic strength, on phase (coil–globule) and volume (swelling–collapse) transitions has been studied. © 2003 Society of Chemical Industry     

Synthesis and characterization of novel linear and crosslinked polyelectrolytes derived from the acetoacetic ester and acrylic acid

Summary Novel linear and crosslinked polyelectrolytes based on acetoacetic ester and acrylic acid were synthesized for the first time via Michael addition reaction followed by radical polymerization. The structure and properties of polyelectrolytes were characterized by FTIR, Raman and NMR spectroscopy, TGA, DSC, GPC, viscometry and potentiometric titration. Considerable influence of water content on the swelling rate of hydrogels was established. The swelling-deswelling properties of hydrogels were studied in dependence of pH, ionic strength and in water-organic solvent mixtures.     

Binary and ternary polymer–strontium complexes and the capture of radioactive strontium‐90 from the polluted soil of the Semipalatinsk Nuclear Test Site

The interaction of poly(acrylic acid) (PAA) and poly(ethylene glycol) (PEG) with strontium ions and the binding of strontium ions by equimolar interpolymer complexes (IPCs) of PAA and PEG were studied. The stability constants of binary polymer–metal complexes were determined. Aqueous solutions of IPCs of PAA and PEG were applied as soil structuring agents in model and real experiments. The ability of IPCs to capture radioactive strontium ions from the polluted soil of the Semipalatinsk Nuclear Test Site was established. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 759–764, 2003     

Interaction of a new anesthetic drug richlocain with linear and weakly crosslinked poly‐N‐vinylpyrrolidone

The properties of complexes of richlocain, a new local anesthetic drug, with linear and weakly crosslinked poly‐N‐vinylpyrrolidone were investigated with changes in media properties of pH, temperature, and solvent thermodynamic quality. The kinetics and activation energy of drug release from the gel matrix were determined. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2977–2981, 2003     

Swelling Behavior and Complex Formation Ability of Ternary Amphoteric Gels based on Allylamine Derivatives and Maleic Acid

Summary: The swelling behavior of an amphoteric gel composed of 50 mol‐% of maleic acid (MA), 25 mol‐% of N,N′‐dimethyldiallylammonium chloride (DMDAAC) and 25 mol‐% of diallylamine (DAA) was studied in aqueous and aqueous‐salt solutions. The isoelectric point (IEP) of the MA‐DMDAAC‐DAA gel determined from swelling experiments was about pH 4.6. Considerable gel swelling with increasing ionic strength was observed at the IEP. Dynamic swelling properties of the amphoteric gel in water with and without added salt were measured at various pH values including the IEP. The swelling behavior of the amphoteric gel was found to depend on the ionization state of the functional groups. It can be described by either a relaxation‐controlled or non‐Fickian (anomalous) mechanism. Swelling‐deswelling properties of the amphoteric gel were also studied in mixtures of water and organic solvents. The amphoteric gel was able to complex sodium poly(styrene sulfonate), sodium lauryl sulfate, the cationic drug richlocain, and the bivalent transition metal ions Cu²⁺, Ni²⁺, Co²⁺, and Zn²⁺. The sorption of polyelectrolyte, surfactant, drug, and metal ions by the amphoteric gel is accompanied by the contraction of the gel network. Partial release of the cationic drug molecules entrapped into the gel volume takes place at the IEP of the amphoteric gel with low activation energy, while neither the anionic polyelectrolyte nor the surfactants are released from the gel interior at the IEP. The swelling‐shrinking behavior of gel‐polyelectrolyte and gel‐surfactant complexes in dependence of pH and ionic strength of the outer solution is similar.

     

Stimuli‐sensitive behaviour of novel betaine‐type polyampholytes

Novel linear and crosslinked polyampholytes of betaine structure based on acrylic acid and ethyl 3‐aminocrotonate (ethyl ester of 3‐amino‐2‐butenoic acid) have been synthesized by Michael addition reaction followed by radical copolymerization. The mechanism of formation of monomer and polymer betaines is discussed. The linear polyampholyte has been characterized by potentiometric titration, IR, NMR and GPC. Crosslinked polymeric betaines were synthesized in the presence of N,N′‐methylenebisacrylamide. The stimuli‐sensitive properties of amphoteric gels have been studied as a function of pH, ionic strength, water–organic mixture composition, electric, and combined electric and magnetic fields. The isoelectric points of linear and crosslinked polymeric betaines correspond to pH 2.0–2.1. The effect of ionic strength on the solution and gel properties of polybetaine has been interpreted on the basis of destruction of inter‐chain, intra‐chain and intra‐group salt bonds. Water–acetone, water–ethanol or water–DMF mixtures cause the shrinking of amphoteric gel due to change of the dielectric constant of the medium and decrease of the osmotic pressure. Electrocollapse is observed under the action of DC electric field. Simultaneously cross action of electric and magnetic fields enhances the collapsing rate. Appearance of pH gradient within the volume of polyampholyte gel under the externally imposed DC electric field has been observed. Copyright © 2003 Society of Chemical Industry