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Natural alkaloid galantamine is widely used for the treatment of Alzheimer’s disease and various other memory impairments. Galantamine hydrobromide (GH) is available as fast-release tablets, extended-release capsules, and oral solution. However, oral delivery of GH can cause side effects, such as nausea, vomiting, and gastrointestinal disturbance. Transdermal delivery is one possible way to avoid such unwanted effects and is also patient friendly, especially for unconscious patients, patients with swallowing difficulties, and patients with mental disturbances. In this work, thermoresponsive copolymer networks based on poly(N-isopropylacrylamide) were studied as new platforms for potential transdermal GH delivery. Series of networks of varied structure and composition were synthesized and investigated by applying swelling kinetics and different spectroscopic and thermal methods. The network films were drug loaded in GH aqueous solution and main characteristics of the obtained GH delivery systems were evaluated. The GH release kinetic profiles in BS at 37 °C were established and discussed.

Nowadays, the modern pharmaceutical investigations are directed toward obtaining of new polymer micro- and nano-sized drug delivery carriers. In this respect, the use of hydrogel carriers based on polyzwitterions (PZIs) is an opportunity in the preparation of polymer drug delivery systems with desired characteristics. This paper describes the synthesis and characterization of micro-structured p(VA-co- DMAPS) systems with different compositions in situ-loaded with Ibuprofen by emulsifier-free emulsion copolymerization (EEC) in water. The mean size of the prepared microparticles was measured by SEM and particles have been visualized by AFM. The inclusion of Ibuprofen in the polyzwitterionic copolymer microgel systems was established by using DSC. In vitro, drug release experiments were carried out in order to estimate the ability of the obtained microgels to modify the release of water-insoluble Ibuprofen.

This paper describes the synthesis and characterization of cationic copolymers with different macromolecular architecture and drug delivery properties of the corresponding dexamethasone sodium phosphate (DSP)-loaded systems. Copolyelectrolytes comprising poly[2-(acryloyloxy)ethyl] trimethylammonium chloride (PAETMAC) and poly(ethylene glycol) blocks as well as a tri-arm star-shaped PAETMAC were synthesized using cerium(IV) ion-mediated polymerization method. The obtained copolyelectrolytes and corresponding ionic associates with DSP have been characterized by 1H NMR, Fourier Transform Infrared spectroscopy, and differential scanning calorimetry. The average diameter, size distribution, and ζ-potential of the copolymers and DSP–copolymer ionic associates were determined by dynamic light scattering, and particles were visualized by scanning electron microscopy and transmission electron microscopy. The biocompatibility and cytotoxicity of obtained copolymers were determined. In vitro drug release experiments were carried out to estimate the ability of the obtained nanoparticles for sustained release of DSP for a period of 24 h. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 103:2406–2413, 2014

Copolymer (vinyl acetate (VA)-co-3-dimethyl(methacryloyloxyethyl)ammonium propane sulfonate (DMAPS)) nanoparticles have been synthesized by radical copolymerization in water. It was established that the variation of the initial monomer feed (DMAPS concentration was 10 mol% (copolymer 1) and 90 mol% (copolymer 2)) changes the copolymerization type, nanoparticles morphology, self-organization and size distribution. The shape, average diameter, size distribution and zeta potential of the copolymer nanoparticles are determined by atomic force microscopy (AFM), dynamic light scattering and zeta potential data, respectively. While the copolymer 1 nanoparticles are solid with spherical shape, average diameter 276 nm and zeta potential −25.2 mV, the copolymer 2 nanoparticles have bean-like shapes with an average diameter 49.3 nm and zeta potential −4.4 mV and contain many domains with different density. For the first time the AFM images of the copolymer 2 nanoparticles presented the unique self-organization of the dipole–dipole clusters of DMAPS units. The results indicated that the obtained copolymer nanoparticles with specific structure could be used as drug delivery systems.

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.

Segmented copolymer networks (SCN) based on poly(2-ethyl-2-oxazoline) and containing 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, and/or methyl methacrylate segments have been evaluated as potential sustained release systems of the water soluble cardioselective β-blocker metoprolol tartrate. The structure and properties of the drug carriers were investigated by differential scanning calorimetry, attenuated total reflectance Fourier transform infrared spectroscopy, scanning electron microscopy, and atomic force microscopy. Swelling kinetics of SCNs in various media was followed, and the conditions for effective MT loading were specified. MT-loaded SCNs with drug content up to 80 wt.% were produced. The release kinetics of metoprolol tartrate from the systems was studied and it was shown that the conetworks of different structure and composition are able to sustain the metoprolol tartrate release without additional excipients.

Polyzwitterions belong to the “smart” polymers’ group because of their specific swelling properties which depend on pH and ionic strength of the aqueous media. Novel polyzwitterionic copolymer nanoparticles of vinyl acetate (VA) and 3-dimethyl(methacryloyloxyethyl)ammonium propane sulfonate (DMAPS) (p(VA-co-DMAPS)) with loaded in situ metoprolol tartrate were synthesized by emulsifier-free emulsion copolymerization in water. The influence of in situ addition of metoprolol tartrate on the emulsifier-free emulsion copolymerization mechanism was studied. It was suggested that the interactions between metoprolol tartrate and the copolymer nanoparticles are responsible for the creation of “bridge” connections between them and these bonds led to the formation of coagulum. To validate possible mechanisms of interaction between metoprolol tartrate and copolymer nanoparticles Differential Scanning Calorimetry was employed. Scanning Electron Microscopy, Atomic Force Microscopy, Dynamic Light Scattering and ζ-potential measurements were used to determine the average diameter, size distribution and ζ-potential of the copolymer nanoparticles. It was shown that the copolymer composition was an effective parameter for control of the release kinetics of in situ loaded metoprolol tartrate in copolymer nanoparticles.

The aim of this study was to synthesize stable copolymer (vinyl acetate-co-3-dimethyl[methacryloyloxyethyl] ammonium propane sulfinate) zwitterionic latex with different compositions for the first time by emulsifier-free emulsion copolymerization. Throughout the course of the study, a proposal was made for the explanation of the relationship between the "overshooting" phenomenon (a swelling kinetics with a maximum) and the specific self-association of the zwitterionic copolymers. The zwitterionic monomer unit mole fraction, pH, and ionic strength effects on this relationship, on the swelling kinetics of the zwitterionic copolymers, and on the sustained verapamil hydrochloride release from the model tablets were established by the study's authors.

New co-polymer zwitterionic matrices for sustained release of verapamil hydrochlorideStable 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 mDMAPSand 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.