Advanced Materials Research Vols. 93-94

Abstract: Pectic polysaccharide from durian rinds (Durio Zibethinus) has been reported to mainly compose of pectin which is generally used in various pharmaceutical dosage forms. The purpose of this research was to investigate the physicochemical properties of spray-dried pectic polysaccharide powders as a function of spray drying conditions (inlet temperature, feed rate, and aspirator rate) and formulation parameters (pectic polysaccharide concentration). A mini spray dryer was used to spray dry pectic polysaccharide in formulation with maltodextrin, colloidal silica and propylene glycol. Production yields were obtained between 31.08 – 52.87%. Higher yield percentage was obtained when the inlet temperature was increased. Particle size of < 7m was from low pectic polysaccharide concentration. The pectic polysaccharide powders were bulky and the shape was almost spherical with smooth surface but collapsed at high inlet temperature and low feed rate. At 75% RH and room temperature, the powders could adsorb moisture of about 12% of the powder weight. The swelling index and mucoadhesion time that the powders attached to the porcine intestine was ranged 14 – 70 and 7 - >30 minutes, respectively. This research provides useful information for development of pectic polysaccharide as fine powder for drug delivery.

Abstract: Tin dioxide (SnO2) materials are prepared by using vapor transport techniques through a vapor-liquid-solid (VLS) mechanism from Tin (Sn) powder. The SnO2 materials are synthesized onto the silicon substrate at temperatures 850 0C. Crystalline structure of SnO2 nanowires was investigated by X-ray diffraction (XRD) spectroscopy. XRD patterns of SnO2 exhibited tetragonal rutile structure with lattice parameters of a = 4.73 oA and c = 3.18 oA. Surface morphology of SnO2 films was characterized by scanning electron microscope (SEM), that SEM micrographs indicate nanowires-like structure. The Raman spectra of single-crystalline rutile SnO2 nanowires were studied, three vibration modes were observed at 475, 635 and 775 cm-1 corresponded to the typical feature of the SnO2 nanowires. A room temperature photoluminescence (PL) spectrum of SnO2 nanowires were in visible emission range.

Abstract: Minitablets can be used either single or multiple unit sustained release dosage form. The objectives of this study were to prepare and evaluate the prolonged action, bioadhesive and slowly dissolving minitablets. The minitablets (Ø 2.5 mm, 7 mg) were prepared by direct compression method using 75%w/w of various hydrophilic polymers: hydroxypropylcellulose (HPC), hydroxypropyl methylcellulose (HPMC), carboxy methylcellulose (CMC), pectin (PT) and chitosan (CS). Spray dried lactose was used as diluent. Prior to compression, the angle of repose, bulk-tab density and %compressibility of each mixed powder were evaluated. The rate of hydration and erosion of the obtained minitablets were carried out in phosphate buffer (pH 7.4). The powder blends containing HPC, CMC or HPMC showed satisfactory flow properties and compressibility. Accordingly, the prepared matrix tablets of HPC, CMC and HPMC showed good physical properties such as hardness, while those of CS and PT showed poor properties. The degree of swelling were ranked as CS>CMC>PT>HPC>HPMC, while the erosion were ranked as CMC≈HPMC≈PT > HPC≈CS. Adhesion time of these minitablets on isolated pig intestine was >30 min for CMC, PT and CS tablets while HPC and HPMC tablets exhibited weaker bioadhesion. In conclusion, among tested polymers, CS, PT and CMC were appropriate for prolonged action, bioadhesive and slowly dissolving minitablets.

Abstract: The ionic conductivity and mechanical properties of poly (vinyl chloride) (PVC)/poly (ethyl methacrylate) (PEMA) polymer blends containing LiN(CF3SO3)2 as doping salt has been studied using electrical impedance spectroscopy (EIS) and Dynamic Modulus Analysis (DMA) as a function of polymer blend ratios and lithium salt concentration. The film with PVC/PEMA composition of 65:35 obtained the highest conductivity with good transparency. DMA showed that both the storage modulus (E') and the glass transition temperature (Tg) of the PVC/PEMA is increased with PEMA concentration. In the case of PVC/PEMA-LiN(CF3SO2)2 films, the conductivity was found to increase with concentration of salt added with a maximum in conductivity at 35 wt.% LiN(CF3SO2)2. The Tg values of the doped films was found to increase with concentration of salt such that the film with the highest conductivity value has the highest Tg.

Abstract: Gallic acid (G) is a natural phenolic compound that has potent antioxidant and antityrosinase activities. The solubility of gallic acid in aqueous system is rather poor. The purpose of this research is to develop the thermosensitive gel containing G based on Lutrol® F127 (L) and the antioxidant of prepared gels was determined using modified ABTS.+ method expressed as Vitamin C Equivalent Antioxidant Capacity (VCEAC) method. N-methyl pyrrolidone (N) could be used to effectively solubilize G into L aqueous systems. This developed thermosensitive system could convert from solution in the cool place to the firm gel under physiological condition on the skin to delivery an anti-aging agent such as gallic acid. Gallic acid gel prepared from hydroxypropyl methyl cellulose (HPMC, H) was employed to compare with the developed system. The developed gel containing 25% L, 25% N and 5% G (L25N25G5) showed the good physical appearances. In vitro release study was performed using the membrane-less method. The release of G from L25N25G5 into citrate-phosphate buffer pH 5.5 was faster than that of the gel containing 3% H, 25% N and 5% G (H3N25G5). From rheology study, L25N25G5 exhibited as a Newtonian flow at 4 °C and plastic flow at 28°C and 35 °C whereas H3N25G5 demonstrated as a pseudoplastic flow at all the three temperatures. Additionally, from VCEAC method, L25N25G5 exhibited a good antioxidant activity.

Abstract: Glass compositions xPbO : 20Na2O : (80-x)B2O3 (x = 5,10,15,20,25,30,35,40,45,50 and 55 %mol) have been prepared using melt-quenching method. The density and molar volume of these glass samples have been found to be compositional dependent. The results indicate that PbO acts on the glass structures were different between the range 0≤ x ≤ 20 %mol and beyond x = 20 %mol (with inflection at x = 20 %mol). These due to the PbO can enter the glass network both as a network modifier and also as a network former. This role depends on the type of bond between lead and oxide. These results are interpreted in term of IR analysis.

Abstract: This work investigates changes in the chemical composition of InON thin films, grown by reactive gas-timing rf magnetron sputtering with different O2:N2 timing ratio characterized by Auger Electron Microscope (AES), Raman Spectroscopy which are well correlated with the electrical properties of films. The existence of nitrogen and oxygen in the deposited InON thin films was revealed by AES. Two Raman active optical phonons have been clearly observed and assigned to InN E1(TO) at ~470 cm-1 and E1(LO) at ~570 cm-1 and also shifted with different O2:N2 timing ratio. The carrier mobility of InON thin films was decreased when the ratio of O2:N2 timing is increased.

Abstract: Two different viscous coating materials, which are Polydimethylsiloxane (PDMS) mixed with 10%wt of Dicumylperoxide (DCP), and Semifluorinate Silane (SFS), were applied to silicon micro-asperity. The cosine’s Young and viscosity of those coating materials are -0.3584,-0.3496 and 3.176x10-3, 1.339 x10-3 Pas, respectively. The rough surfaces with nine asperity shapes were studied. The results shown that, pillar shape has an effect on water contact angle (WCA): Stripe asperity cannot make the average WCA greater than 150. When consider the pillar asperity, the WCA falls between 152 and 157, which exhibits a superhydrophobic surface property. However, actual WCA of the micro-asperity coated with PDMS+10%wt of DCP is lower than that coated with SFS around 1 to 7. High viscous material makes the asperity size bigger than the design and decreases the WCA: the low viscous material is more suitable for coating on the asperities.

Abstract: Polypropylene (PP) samples grafted with Maleic Anhydride (MA) were prepared by reactive blending via co-rotating twin screw extrusion. The PP was functionalized in the presence of an optimized amount of precursor, Dicumyl Peroxide (DCP) and MA. The amounts of MA grafted on PP were checked by standard test method for acid number. Maleated PP as a compatibilizer with the highest acid number was added to PP/Polyamide 6 (PA6) and blended in the twin screw extrusion. It was found that the PP-g-MA enhanced tensile properties as well as the izod impact properties of notched samples of PP/PA6/PP-g-MA blends compared to neat polypropylene. The scanning electron microscope confirmed the good adhesion of PA6 on PP matrix.

Abstract: Series of multi-component glass systems of the following chemical composition SiO2-Na2O-CaO-Nd2O3 with an increasing of rare earth concentration, the effect of Nd2O3 on the optical properties of the glass systems is investigated. On the basis of the measure values of densities and refraction, Nd3+ ion concentration in glasses and several other physical properties were determined. The absorption coefficient, both direct and indirect optical energy gaps, and Urbach energy are evaluated using the absorption edge calculations. The different factors that play a role for controlling the refractive indices such as electronic polarizability, bridging and non-bridging oxygen, and optical basicity are discussed in accordance with the obtained index data. The non-crystalline phase identified basing on X-ray diffraction analysis.