Electrostimulated shift of the precipitation temperature of aqueous polyzwitterionic solutions

Georgiev, Georgi V.; Tzoneva, Anna A.; Lyutov, L.; Iliev, Stefko B.; Kamenova, Irena; Georgieva, Ventseslava; Kamenska, Elena; Bund, Andreas

doi:10.1002/masy.200450644

Cited by 18 publications

(10 citation statements)

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“…have been described only briefly, 25,49,51,62 data on the UCST behaviour of these polymers are more scarce, or are even missing completely. Monomers 2, 3 and 6-8, and their polymers are new compounds.…”

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confidence: 99%

“…The strong dependence of the cloud points of P-1 on the concentration and on the type of added inorganic salts, in particular on the anion type in close correlation to the Hofmeister series, is well established. [20][21][22][23]43,57,[77][78][79][80][81][82] Therefore, the strong effects of the added salts and their relative impacts, observed for structurally closely related polymers P-2-P-8 are not surprising. Still, the widespread perception that the interaction of salts with polysulfobetaines can be treated as a general saltingin effect is not adequate, as evident from the evolution of the cloud points as a function of salt concentration.…”

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confidence: 99%

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Effect of the zwitterion structure on the thermo-responsive behaviour of poly(sulfobetaine methacrylates)

Hildebrand

Laschewsky

Päch³

et al. 2017

Polym. Chem.

135

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A series of new sulfobetaine methacrylates, including nitrogen-containing saturated heterocycles, was synthesised by systematically varying the substituents of the zwitterionic group. Radical polymerisation via the RAFT (reversible addition-fragmentation chain transfer) method in trifluoroethanol proceeded smoothly and was well controlled, yielding polymers with predictable molar masses. Molar mass analysis and control of the end-group fidelity were facilitated by end-group labeling with a fluorescent dye. The polymers showed distinct thermo-responsive behaviour of the UCST (upper critical solution temperature) type in an aqueous solution, which could not be simply correlated to their molecular structure via an incremental analysis of the hydrophilic and hydrophobic elements incorporated within them. Increasing the spacer length separating the ammonium and the sulfonate groups of the zwitterion moiety from three to four carbons increased the phase transition temperatures markedly, whereas increasing the length of the spacer separating the ammonium group and the carboxylate ester group on the backbone from two to three carbons provoked the opposite effect. Moreover, the phase transition temperatures of the analogous polyzwitterions decreased in the order dimethylammonio > morpholinio > piperidinio alkanesulfonates. In addition to the basic effect of the polymers' precise molecular structure, the concentration and the molar mass dependence of the phase transition temperatures were studied. Furthermore, we investigated the influence of added low molar mass salts on the aqueous-phase behaviour for sodium chloride and sodium bromide as well as sodium and ammonium sulfate. The strong effects evolved in a complex way with the salt concentration. The strength of these effects depended on the nature of the anion added, increasing in the order sulfate < chloride < bromide, thus following the empirical Hofmeister series. In contrast, no significant differences were observed when changing the cation, i.e. when adding sodium or ammonium sulfate.

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confidence: 99%

Effect of the zwitterion structure on the thermo-responsive behaviour of poly(sulfobetaine methacrylates)

Hildebrand

Laschewsky

Päch³

et al. 2017

Polym. Chem.

135

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“…According to the above mentioned requirements to polymer matrices for drug tablets, EFC of the ZI comonomer with a poor water soluble monomer was preferred, and the swelling properties of the polyzwitterion (PZI) matrices produced were studied. Although there are some publications for EFC of ZI monomers,20–25 data for preparation and properties of the copolymer of vinyl acetate (VA) and 3‐dimethyl(methacryloyloxyethyl)ammonium propanesulfonate (DMAPS) are not found. This stimulated the synthesis and characterization of poly{(vinyl acetate)‐ co ‐[3‐dimethyl(methacryloyloxyethyl)ammonium propanesulfonate]}s (p(VA‐co‐DMAPS)) as polymer matrices for sustained drug release.…”

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confidence: 99%

“…26–28 These clusters, playing the role of the physical junction points are destroyed in the presence of a low‐molecular mass salt (LMS) and the PZI macromolecules swell (the right hand side in Figure 1). This is the essence of the antipolyelectrolyte effect (APE), characteristic of PZI 29–31. Upon swelling of the PZI macromolecules, the hydrophobic fragments are associated in hydrophobic cores, coated with a hydrophilic shell, consisting of co‐ions and their counterion atmosphere (the right hand side in Figure 1).…”

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confidence: 99%

Emulsifier‐Free Emulsion Copolymerization of Vinyl Acetate and 3‐Dimethyl(methacryloyloxyethyl)ammonium Propanesulfonate and Swelling Behavior of their Copolymer Matrices

Kamenska

Kostova

Ivanov

et al. 2007

Macro Reaction Engineering

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Stable poly{(vinyl acetate)‐co‐[3‐dimethyl(methacryloyloxyethyl)ammonium propanesulfonate]} latexes with different compositions were synthesized by emulsifier‐free emulsion copolymerization. An unusual “overshooting” behavior of the copolymer tablets is explained based on the formation of specific clusters of oppositely oriented dipoles. The variation of their concentration with the zwitterionic monomer unit fraction, ionic strength and temperature is responsible for the differences in the swelling kinetics established. The results show that these parameters can be used to control swelling degree of copolymer matrices and their sustained drug delivery.

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“…Their self-association in an aqueous solution is due to the dipole-dipole interactions, leading to the formation of dipole-dipole clusters (DDC) (the left hand side in Fig. 1) (13)(14)(15)(16)(17)(18). These DDCs are destroyed in the presence of a low-molecular-mass salt (LMS) and the PZI macromolecules swell (Fig.…”

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New co-polymer zwitterionic matrices for sustained release of verapamil hydrochloride

Kostova¹,

Rachev²

2007

Acta Pharmaceutica

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Stable co-polymer [vinyl acetate-co-3-dimethyl(methacryloyloxyethyl) ammonium propane sulfonate, p(VA-co-DMAPS)] latex of different compositions has been synthesized for the first time by emulsifier-free emulsion copolymerization. The unusual >>overshooting<< behavior of the co-polymer tablets has been explained by the formation of specific clusters from the opposite oriented dipoles-zwitterionic species. The change of their concentration with the DMAPS unit fraction (mDMAPS), pH and ionic strength has been considered responsible for the differences observed in the swelling kinetics. The results obtained prove that mDMAPS and ionic strength could be used to control the swelling degree of the p(VA-co-DMAPS) matrices and their sustained drug delivery. In this way, p(VA-co-DMAPS) matrices could be effectively used to control the sustained release of drugs with basic properties like verapamil hydrochloride from model tablets.

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Electrostimulated shift of the precipitation temperature of aqueous polyzwitterionic solutions

Cited by 18 publications

References 0 publications

Effect of the zwitterion structure on the thermo-responsive behaviour of poly(sulfobetaine methacrylates)

Effect of the zwitterion structure on the thermo-responsive behaviour of poly(sulfobetaine methacrylates)

Emulsifier‐Free Emulsion Copolymerization of Vinyl Acetate and 3‐Dimethyl(methacryloyloxyethyl)ammonium Propanesulfonate and Swelling Behavior of their Copolymer Matrices

New co-polymer zwitterionic matrices for sustained release of verapamil hydrochloride

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