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Optically isotropic nature can open a new type of high-performance liquid crystal (LC) displays. The main features emerge from the interaction between LC and polymer network at the interface. At this point, we investigated the influence of cross-linking monomer concentration and functionality on electro-optic properties of optically isotropic liquid crystal (OILC) obtained by polymerisation-induced phase separation method. Interestingly, we obtained a pore-like network structure constructed by highly interlinked polymer beads in acrylate monomers and achieved fast decay response time (0.6 ms). We found that the voltage-dependent hysteresis was mostly eliminated (~0.25%), and the contrast ratio was enhanced (1:1550) for high functional monomers. The result inspires a simple way to optimise the materials to fabricate a high-performance OILC device and it shows high-transparency, low-driving voltage, hysteresis-free and sub-millisecond response time. [ABSTRACT FROM AUTHOR]

Biocompatible polymers have played an integral role in the advancement of drug delivery systems. The discovery of a novel polymer with innovative properties can provide great opportunities to enhance drug efficacy as well as reduce side effects. In this study, a novel disulfide polymer was synthesized and characterized. Its mono-mer is alpha-lipoic acid (ALA), which is synthesized in all cells in the human body. The disulfide polymer was obtained by the simple thermal polymerization of crystal-line particles at a temperature higher than its melting point, followed by precipitation purification. It had rubbery and sticky characteristics. In vitro release tests demon-strated that the disulfide polymer had both pH-dependent degradation and related sustained release profiles, with a degraded form of ALA. Therefore, this novel class of responsive polymers that can be prepared by simple thermal polymerization has pronounced potential to contribute to future drug delivery systems. [ABSTRACT FROM AUTHOR]

Purpose: This article was intended to improve the efficacy of alpha-lipoic acid (ALA) for appetite suppression by controlling the particle size and self-polymerization of ALA. Methods: ALA was fabricated into micro- and nanoparticles, and the efficacy and in vitro release were investigated. Because of the self-polymerization of ALA into poly[3-( n-butane carboxylic acid)propyl]disulfide (PBCPD) by processing heat, low-speed rotation comminution was used to control PBCPD content. Results: The ALA particle size initially decreased and then increased after 10 hours of nanocomminution, indicating aggregation related to PBCPD formation. The in vitro release of ALA was significantly reduced by the existence of PBCPD. Interestingly, the reduction was not followed by a decrease in efficacy. Alternatively, the food intake was significantly reduced by ALA particles containing more than 30 mol% PBCPD. Conclusions: When the particle size and self-polymerization of ALA were carefully controlled, the efficacy on appetite suppression could be superior to water-soluble ALA salt. The ALA particles might have a composite nanostructure of ALA and PBCPD. [ABSTRACT FROM AUTHOR]

The reduction of particle size to nanometers has been an important tool used for efficient drug delivery. Solid drug nanoparticles can be conveniently prepared by nanocomminution. This process relies on mechanical energy and the selection of a proper polymeric stabilizer. The long chains of polymers provide steric stabilization for drug nanoparticles. In this research, itraconazole and hydroxypropyl cellulose were used to study the effect of the molecular weight of a polymer on particle size reduction. In principle, an increase in molecular weight produces two counteracting effects: a decrease in the diffusion rate of chains and an increase in the physical adsorption of a polymer. The effects of particle size reduction are more pronounced in systems involving smaller molecular weights, and the effects of changing molecular weights disappear with time. Systems of higher molecular weight show larger aggregates in their redispersion after drying. Based on the results of our research, it appears that polymers of smaller molecular weight are more suitable than larger polymers for efficient nanocomminution. This indicates that the kinetic aspects of molecular weight are important. [ABSTRACT FROM AUTHOR]