Supramolecular hydrogels as drug delivery systems.

Drug delivery from a hydrogel carrier implanted under the kidney capsule is an innovative way to induce kidney tissue regeneration and/or prevent kidney inflammation or fibrosis. We report here on the development of supramolecular hydrogels for this application. Chain-extended hydrogelators containing hydrogen bonding units in the main chain, and bifunctional hydrogelators end-functionalized with hydrogen bonding moieties, were made.

Improvements of reinforced silica aerogel nanocomposites thermal properties for architecture applications.

An 1,4-cis polybutadiene rubber/carboxymethyl starch (CMS)-based silica aerogel nanocomposites as a insulation material was developed that will provide superior thermal insulation properties, flexibility, toughness, durability of the parent polymer, yet with the low density and superior insulation properties associated with the aerogels. In this study, reinforced 1,4-cis polybutadiene-CMS-silica aerogel nanocomposites were prepared from a silica aerogel with a surface area 710 m(2) g(-1), a pore size of 25.3 nm and a pore volume of 4.

Improvement of reinforced concrete properties based on modified starch/polybutadiene nanocomposites.

A novel polymer-modified cement concrete with carboxymethyl starch (CMS) and 1,4-cis polybutadiene (PBD) system by mixing polymer dispersions or redispersible polymer powders with the fresh mixture have been examined. In this paper, the addition of CMS-PBD powders in an aqueous solution is studied. Polymeric molecules are supplied on a molecular scale, improving the approach of the relatively large cement grains by the polymers.

Synthesis and characterization of modified starch/polybutadiene as novel transdermal drug delivery system.

Transdermal drug delivery systems are topically administered medicaments in the form of patches that deliver drugs for systemic effects at a predetermined and controlled rate. It works very simply in which drug is applied inside the patch and it is worn on skin for long period of time. Polymer matrix, drug, permeation enhancers are the main components of transdermal drug delivery systems.

The novel polymeric systems for photodynamic therapy technique.

Photodynamic therapy (PDT) is a medical treatment in which a combination of a photosensitizing drug and visible light causes destruction of selected cells. Over the past two decades, photodynamic therapy has enjoyed a period of laboratory and in the clinic. Although still widely considered to be an experimental technique, its status and value within modern clinical practice continues to grow.

Synthesis and in-vitro photodynamic studies of the superparamagnetic chitosan hydrogel/chlorin E6 nanocarriers.

The objective of the present study was to develop superparamagnetic chitosan(CS) � dextran sulfate(DS) hydrogels as a intelligent drug system for effective carrying of Chlorin E6(chn E6) photosensitizer to cancer cells. This system can be detectable by magnetic Resonance Imaging technique. The study shows that the lifetime of the triplet state for chn E6 photosensitizer is significantly increase when encapsulate into hydrogel.

Synthesis and characterization of modified starch hydrogels for photodynamic treatment of cancer.

The objective of the present study was to develop carboxymethyl starch (CMS) and dextran sulfate (DS) hydrogels that are able to efficiently encapsulate 5-,10-,15-,20-tetrakis(meso-hydroxyphenyl)porphyrin (mTHPP), a porphyrin-based PS agent. The study showed that the lifetime of the triplet state for porphyrin PS is significantly increase when encapsulate into hydrogel. In addition to the possible enhancement of ¹O₂ generation, other advantages to incorporating porphyrin-based PS agents into hydrogel include the ability to solubilize these generally hydrophobic agents, the small and uniform size of hydrogels, and potential for passive targeting of solid tumors via the enhanced permeation and retention effect decreasing systemic photosensitization.

Synthesis and in vitro studies of biodegradable modified chitosan nanoparticles for photodynamic treatment of cancer.

The main aim of this research is to study the in vitro photocytotoxicity and cellular uptake of biodegradable polymeric nanoparticles loaded with photosensitizer mTHPP. As the first part of a continued research on conversion of N-sulfonato-N,O-carboxymethylchitosan (NOCCS) to useful biopolymer-based materials, large numbers of carboxylic functional groups were introduced onto NOCCS by grafting with polymethacrylic acid (PMAA). The free radical graft copolymerization was carried out at 70°C, bis-acrylamide as a cross-linking agent and persulfate as an initiator.

Synthesis and characterization of pH-dependent glycol chitosan and dextran sulfate nanoparticles for effective brain cancer treatment.

A novel drug delivery system for the treatment of brain tumors was formulated by methotrexate (MTX)-loaded polymeric nanoparticles (NPs) based on Glycol chitosan (GCS) and Dextran sulfate (DS). The physicochemical properties of resulting particles were investigated, evidencing the contribution of these nanoparticles for brain targeting. In vitro release of MTX was also evaluated.

Synthesis and in vitro studies of biodegradable thiolated chitosan hydrogels for breast cancer therapy.

Local drug delivery strategies have gained momentum recently as a promising modality in cancer therapy. In order to deliver Letrozole (LTZ) at the tumor site in therapeutically relevant concentrations, acetyl-polyamidoamine (Ac-PAMAM)-thiolated chitosan (TCS) films were fabricated. LTZ could be loaded at 31% wt/wt in films, which were translucent and flexible.

Development and in vitro evaluation of thiolated chitosan--Poly(methacrylic acid) nanoparticles as a local mucoadhesive delivery system.

The main objective of this study was to develop a local, oral mucoadhesive metronidazole benzoate (MET) delivery system that can be applied and removed by the patient for the treatment of periodontal diseases. The results of present study revealed that the retention time of MET at its absorption site could be increased by formulating it into nanoparticles using thiolated chitosan (TCS)-poly(methacrylic acid) (PMAA). The nanoparticles of MET prepared from TCS-PMAA may represent a useful approach for targeting its release at its site of absorption, sustaining its release and improving its oral availability.

Synthesis and in vitro evaluation of carboxymethyl starch-chitosan nanoparticles as drug delivery system to the colon.

The purpose of this study was to examine chitosan (CS)-carboxymethyl starch (CMS) nanoparticles as drug delivery system to the colon. The 5-aminosalicylic acid (5-ASA) was chosen as model drug molecule. CS-CMS nanoparticles were formulated by a complex coacervation process under mild conditions.

Synthesis and characterization of chitosan hydrogels containing 5-aminosalicylic acid nanopendents for colon: specific drug delivery.

The main aim of this research was to develop and evaluate a multiparticulate system of Ac-poly(amidoamine)(PAMAM)(G4)-chitosan (CS) hydrogels exploiting pH-sensitive and specific biodegradability properties for colon-targeted delivery of 5-aminosalicylic acid (5-ASA). All formulations were evaluated for particle size, encapsulation efficiency, swellability, and in vitro drug release. The size of the hydrogel was found to nanorange.