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Abstract : Nanoencapsulation of Antitumor and Antituberculosis Drug Preparations with Biocompatible Polymers
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Abstract: Controlled release of drugs at the locus of the targeted disease is one of the most challenging research areas in the pharmaceutical field. Nowadays novel drug delivery systems on the basis of polymers are attracting great attention since they can improve therapeutic efficiency of potent drug preparations decreasing the risk of side effects. By developing colloidal drug delivery systems such as liposomes/vesicles and polymeric nanoparticles and nanocapsules the pharmacokinetics of the drug can be changed and thus the therapeutic efficiency of the drug can be increased. Nanoparticles with their special characteristics such as small particle size, large surface area and high capacity of carrying biologically active substances offer a number of advantages compared to other colloidal drug delivery systems [1, 2]. Controlled drug release systems are constructed on the basis of natural and biocompatible synthetic polymers. Among the most promising biocompatible polymers human serum albumin (HSA), polyalkyl cyanoacrylates (PACA) and poly-D,L-lactic acid (PLA) are of great importance. Nanoparticles on their basis have been proven to be efficient in treatment of serious and long-termed diseases such as tumors, tuberculosis and bacterial infections [3-126]. Therefore this article is aimed to give a brief review on the research works devoted to the synthesis and investigation of polymeric nanoparticles and nanocapsules based on PACA, HSA and PLA for the past three decades. Keywords: Drug delivery systems,nanoparticles, nanocapsules, polyalkyl cyanoacrylates, human serum albumin, poly-D,L-lactic acid. Download Full Article |
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Abstract: The Mediterranean fruit fly (medfly), Ceratitis capitata (Wied.) is considered a serious pest of citrus fruits in the southeast of Brazil because of the direct economic impact they have on fruit production and quarantine restrictions for fruit exports. Monitoring and detection of the medfly, using food bait and synthetic attractants, is a key step towards signalling the need for management and control. The aim of this study has been to verify the attractiveness of innovative nanofiber formulations with Trimedlure (TML) for the male of C. capitata in laboratory and field cage tests. Material and Methods:The nanofibers were produced by solution or emulsion electrospinning, containing TML and polymers, such as polycaprolactone, PEG-polycaprolactone, ethyl cellulose and polyvinyl acetate-PVP.
Results: At the laboratory the electrophysiological responses were accessed by the eletroanntenogram technique and in the field by the cage test. The bioactivity of C. capitata antennae was highest when stimulated with all TML nanofiber treatments rather than their controls. There were no differences among the TML nanofiber treatments. In the field cages the same number of medflies were found on the adhesive traps baited with one of each of the TML nanofibers. Keywords: Medfly, electrospinning, nanofibers, pheromone dispenser. Download Full Article |
Abstract : New Polymer Syntheses Part: 55#. Novel Conducting Arylidene Polymers and Copolymers Based on Methyl-Cyclohexanone Moiety
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Abstract: A new interesting class of conducting polymers based on methyl-cyclohexanone in the polymer main chain has been synthesized by solution polycondensation of terephthalaldehyde with methyl-cyclohexanone. Copolymers containing different cycloalkanone moieties were also synthesized using solution polycondensation technique. The model compound I was synthesized by the interaction of methyl-cyclohexanone monomer with benzaldehyde, and its structure was confirmed by elemental and spectral analyses. The resulting new polymers and copolymers were characterized by elemental and spectral analyses, beside solubility and viscometry measurements. The thermal properties of those polymer and copolymers were evaluated by TGA, DrTGA and DTA measurements and correlated to their structural units. PDT as well as T10 was in the range from 205 to 370 ºC. In addition, T10 thermal stability for all the polymers was in theorder: VI> II > III > IV > V. X– ray analysis showed that it has some degree of crystallinity in the region 2q = 5 – 60 degree.The UV– visible spectra of some selected polymers were measured in DMSO solution and showed absorption bands in the range 265-397 nm, due to n – p* and p – p* transition. The morphological properties of copolymer IV as selected examples were tested by SEM. The electrical conductivities of the synthesized polymers and copolymers enhanced to become in the range of 10-9-10-8 S cm-1 by doping with iodine. Keywords: Synthesis, Characterization, Polycondensation, Conducting Polymers, Conducting Copolymers. Download Full Article |
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Abstract: Two new series of polyamides and copolyamides based on methyl-cyclohexanone and tertiary-butyl-cyclohexanone in the main chain were synthesized via the solution polymerization of 2,6-bis(m-aminobenzylidene)-methylcyclohex-anone VI, 2,6-bis(m-aminobenzylidene)tertiary-butyl-cyclohexanone VIII, and its copolyamides with p-phenylene diamines and m-phenylene diamines with diacid chlorides of thianthrene (2,7-Dichloroformylthianthrene-5,5`,10,10`-tetraoxide IV. These polyamides and copolymides ranged from yellow to orange color and had inherent viscosity up to 0.35-0.89 dL/g. All the polyamides and copolymides were insoluble in common organic solvents but dissolved completely in concentrated H2SO4. The thermal stabilities of the prepared polyamides were evaluated by TGA and DTG analyses. X– ray analysis showed these polymers having low degree of crystallinity in the region 2q = 5 – 60°. The morphological properties of some selected polyamides were detected by SEM. Keywords: Polyamides, Copolyamides, Thianthrene, Thermal Properties, arylidene polymers.Download Full Article |
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Abstract: A new interesting class of linear unsaturated polycarbonates based on methyl- cyclohexanone and 4-tert. butyl- cyclohexanone moieties has been synthesized. An interfacial phosgenation technique carried out at ambient temperature was used for the synthesis of these polycarbonates. The resulting polycarbonates were characterized by elemental analyses, infrared spectroscopy,1H nuclear magnetic resonance spectral analyses, viscometry, differential scanning calorimetry and thermogravimetric analysis measurements. All the polycarbonates were soluble in polar solvents like dimethylsulphoxide and sulphuric acid. The crystallinity of some selected polycarbonates was examined by X-ray analysis. In addition, the morphology of selected examples of the polycarbonates was examined by scanning electron microscopy. Keywords: Characterization, Synthesis, polycarbonates, Polycondensation, Unsaturated Diols.Download Full Article |