Nophawan Paradee

Electrically controlled release of benzoic acid from poly(3,4-ethylenedioxythiophene)/alginate matrix: effect of conductive poly(3,4-ethylenedioxythiophene) morphology.

A drug-loaded conductive polymer/hydrogel blend, benzoic acid-loaded poly(3,4-ethylenedioxythiophene/alginate (BA-loaded PEDOT/Alg) hydrogel, was used as a carrier/matrix for an electrical stimuli transdermal drug delivery system (TDDS). The effects of cross-linking ratio, PEDOT particle size, and electric field strength on the release mechanism and the diffusion coefficient (D) of BA were examined by using a modified Franz-diffusion cell. The diffusion scaling exponent value of BA is close to 0.5 which refers to the diffusion controlled mechanism, or the Fickian diffusion as the BA release mechanism. The D increased when there was a decrease in the cross-linking ratio due to the mesh size-hindering effect. When increasing electric field strength, the D of BA-loaded PEDOT/Alg hydrogel increased because the cathode-BA(-) electrorepulsion, electroinduced alginate expansion, and PEDOT electroneutralization simultaneously occurred. The highest D belonged to a blend with the smallest PEDOT particle and highest electrical conductivity. The D of BA was a function of the matrix mesh size except when drug size/mesh size was lower than 2.38 × 10(-3), where D of BA became mesh size independent as the matrix mesh size was extremely large. Thus, the fabricated conductive polymer hydrogel blends have a great potential to be used in TDDS under electrical stimulation.

Encapsulation of Folic Acid in Zeolite Y for Controlled Release via Electric Field.

Zeolite Y/alginate hydrogel was used as a drug carrier/matrix for an electrophoresis transdermal drug delivery system. Folic acid (FA) as a model drug was loaded into the zeolite Y/alginate hydrogel via an ion-exchange process. The effects of cross-linking ratio, Si/Al ratio, electric field strength, and electrode polarity were investigated with respect to the release mechanism and diffusion coefficient (D) of FA using a modified Franz-diffusion cell. The FA was released from the matrix through the diffusion-controlled mechanism or Fickian diffusion because the diffusion scaling exponent value of FA was close to the value of 0.5. The D increased with an increasing cross-linking ratio and Si/Al ratio due to the mesh-size-promoting and the aluminum-content effects. The electric field strength enhanced the D of FA from the anode-FA electroreplusion. In addition, the D of FA could be varied by the electro-attractive or electro-repulsive force between the positively charged FA and the charged electrode depending on whether cathode or anode was placed on the drug matrix. Thus, the fabricated zeolite/hydrogel is of great potential to be used in an electrically controlled transdermal drug delivery system where drug diffusion can be precisely activated and controlled at the time of application.

Controlled release of acetylsalicylic acid from polythiophene/carrageenan hydrogel via electrical stimulation

Blends between polythiophene (PTh) and a carrageenan hydrogel were fabricated as the matrix for the electric field assisted drug release. The pristine carrageenan and the blend films were prepared by the solution casting using acetylsalicylic acid (ASA) as the anionic model drug and Mg(2+), Ca(2+), and Ba(2+) as the crosslinking agents. The ASA was released by the Fickian diffusion mechanism. The diffusion coefficient decreased with increasing crosslinking ratio or decreasing crosslinking ionic radii. The diffusion coefficients were greater with the applied electrical potentials by an order of magnitude relative to those without electric field. Moreover, the diffusion coefficients with PTh as the drug carrier were higher than those without PTh. Thus, the presence of the conductive polymer in the hydrogel blend coupled with applied electric field is shown here to drastically enhance the drug delivery rate.

Permeation Study of Indomethacin from Polycarbazole/Natural Rubber Blend Film for Electric Field Controlled Transdermal Delivery

Transdermal drug delivery is an alternative route to transport the drug into the blood system. This method has been continuously developed to overcome limitations and is now suitable for a wide variety of drug molecules. In this work, the influences of electric field and conductive polymer were investigated for developing a unique drug delivery system from double-centrifuged natural rubber (DCNR) matrix. Indomethacin (IN) was loaded into polycarbazole (PCz) as a conductive polymer drug host to promote the efficient transportation of the drug. The IN-loaded PCz was blended with DCNR to form a transdermal patch. The permeation of IN through the PCz/NR film and pig skin was carrried out by a modified Franz diffusion cell. The IN diffused from DCNR film by the diffusion controlled combined with erosion mechanism depending on the pore formation period. The drug permeation increased with decreasing cross-link ratio because of more accessible pathways for the drug permeation. Moreover, an electric field and the inclusion of PCz as the drug carrier dramatically improved the diffusion of the drug from the membrane by through the electrorepulsive force and electro-reduced PCz expansion. Thus, the PCz/DCNR films are shown here as a potential transdermal patch under applied electric field.

Effect of electrolytes on electrochromic properties and morphology of poly(2,5-dimethoxy aniline) films

Poly(2,5-dimethoxyaniline) (PDMA) was electrochemically synthesized in oxalic (H2C2O4) nitric (HNO3) and hydrochloric (HCl) acids and deposited onto flexible indium tin oxide at various synthesis times and deposition potentials as electrochromic materials. The PDMA films were characterized by FT-IR-spectrometry, scanning electron microscopy, UV-Vis spectrophotometry and cyclic voltammetry. All PDMA films show reversible colour changes from yellow to green corresponding to the transition from the fully reduced state to the fully oxidized state under potential switching. The surface morphology and thickness of PDMA films depend critically on the type of acids used in the electrochemical polymerization process. The morphology of PDMA are highly porous microfibres (H2C2O4 and HNO3), tiny granular aggregate (HCl) and particle agglomerate depending on the polymerization time. The fastest response time observed via colour changing of 3.7 s is obtained from the HCl-PDMA film at 3.5 volt and at the synthesis time of 6 min, as primarily due to the thickness of the film. The flexible PDMA film is demonstrated here as a potential candidate to be used in electrochromic devices.

Influence of Sulfonated Graphene Oxide on Sulfonated Polysulfone Membrane for Direct Methanol Fuel Cell

ABSTRACT Novel proton exchange membranes consisting of an inorganic filler, namely sulfonated graphene oxide, embedded in sulfonated polysulfone were fabricated. The membrane performance depended on the sulfonated graphene oxide content possessed the functional groups to provide the interfacial interaction with sulfonated polysulfone through ionic channels and blocking effect. The membrane with 3% v/v sulfonated graphene oxide content embedded in the matrix was shown to be suitable for direct methanol fuel cell applications. The membrane exhibited the highest proton conductivity of 4.27 × 10−3 S cm−1 which was higher than that of Nafion117. Moreover, the membrane provided the lowest methanol permeability of 3.48 × 10−7 cm2/s which was lower than that of Nafion117. GRAPHICAL ABSTRACT

Synthesis of Poly (2,5-dimethoxyaniline) and Electrochromic Properties

Poly(2,5-dimethoxyaniline) (PDMA) was synthesized using electrochemical polymerization of DMA in oxalic acid. The PDMA film coated onto ITO glass was studied for its chemical structure, morphology, electro-deposition, and electro-activity by FT-IR, TGA, SEM, cyclic voltammetry, and UV-Vis spectrophotometry. The PDMA film showed reversible color changes from yellow to blue representing the transition between the fully reduced state to the fully oxidized state upon switching the potentials. The response time of the PDMA film in term of color change was investigated under various applied potentials and different types of acid electrolyte (HCl and H2SO4). The fast response time of less than 2 sec was observed at the applied potential of 1.6 V. In comparison with HCl, the use of H2SO4 as an electrolyte resulted in the fastest response time. Thus, the PDMA is a potential candidate in electrochromic devices due to its reversible color change and fast response time.

Gelatin-Coated Magnetite Nanoparticles for Drug Delivery System

C is one of the first metals which had been used since the Neolithic age. Malachite, azurite and chrysocolla are included in the mineral categories which contain copper as hydroxi-carbonate compounds. With the direct smelting technology using electric arc furnace method, high-to-middle grade of malachite ore can be smelted and performed a reduction reaction directly which produce copper with few impurities. This research is conducted by direct smelting of malachite ore with 15.66% Cu. According to the test results and data analysis regarding the obtained research, the highest Cu grade and recovery (87.09% Cu and 94.95% recovery) is on 7 minutes of holding time, while the lowest Cu grade and recovery (29.97% Cu and 2.3% recovery) is on 2 minutes of holding time. The phases of the metal product according to XRD analysis with holding time variations are Cu and Fe. There is an occurrence of dissolved Cu in the slag with the highest percentage (3.99%) on 2 minutes of holding time and the lowest one (0.41%) on 5 minutes of holding time. The identified phases which occur in slags are pyroxene, fayalite, silicon carbide, chalcocite and magnetite.

Porous zeolite y-alginate hydrogel composites for electrically controlled transdermal drug delivery

M wild plants commonly used in folk medicine, such as different species from the genus Lathyrus, may represent new sources of biologically active compounds. Therefore, the study of the composition and (bio)chemical behaviour of extracts from these plants may provide valuable information. Several Lathyrus species have been studied: L. aureus, L. pratensis, L. czeczottianus and L. nissolia. Extracts from these plants were analyzed by high-performance liquid chromatography with electrospray ionization mass spectrometric detection (HPLC-ESI-MSn) to determine their phenolic profile. The in vitro antioxidant activity and enzyme inhibitory evaluation were also investigated. The main phenolic compounds (flavonoids and saponins, mainly) and the antioxidant and enzyme inhibition results are here reported. The phenolic contents and the (bio)chemical properties of the analyzed extracts presented significant variations in the different Lathyrus species. However, the high number of phenolic compounds and the antioxidant and enzyme assays suggest that these plants may be further used in phytopharmaceutical or food industry applications.