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Methacrylate Copolymer (methacrylate + copolymer)
Selected AbstractsImprovement in site-specific intestinal absorption of furosemide by Eudragit L100-55JOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 4 2001T. Terao Furosemide (frusemide) is a weakly acidic diuretic drug. Its absorption is poor and variable, in part due to its restricted sites of absorption, mainly the stomach. The narrow absorption window of this drug can be explained by pH partition theory. The purpose of this study was to investigate the feasibility of widening the absorption window of furosemide by controlling the pH in distal portions of the gastrointestinal tract with officially used additives. Methacrylate copolymer (Eudragit L100,55), hydroxypropylmethylcellulose phthalate (HP-55) and hydroxypropylmethylcellulose acetate succinate (AS-MF) were selected as additives. The pH of suspensions of these additives was about 4, and the pH was adjusted to about 6,7 by the addition of NaOH. The Eudragit L100,55 suspension was found to be the most resistant to NaOH titration. When Eudragit L100,55 was used in an in-situ ileal loop experiment in rats, the pH of the intestinal contents was significantly reduced, from 7.9 ± 0.1 to 5.7 ± 0.1, and the plasma concentration of furosemide 15 min after administration was about 3 times higher than that in controls, 1.81 ± 0.42 ,g mL,1 vs 0.63 ± 0.08 ,g mL,1. However, the plasma concentration of [14C] mannitol was not changed by the co-administration of Eudragit L100,55. Furthermore, the AUC of furosemide was significantly increased by a factor of about 1.6 relative to that in controls by the co-administration of Eudragit L100,55, to 21.4 ± 4.0 ,g h mL,1 from 13.3 ± 3.9 ,g h mL,1, and the gastrointestinal pH in the midgut and ileum was significantly reduced, with most of the furosemide remaining in these segments at 2 h following the oral administration of furosemide with Eudragit L100,55 to rats. These findings clearly demonstrate that the addition of Eudragit L100,55 can increase the absorption of furosemide in distal portions of the gastrointestinal tract. In conclusion, it is feasible to widen the absorption window of furosemide by controlling the pH in distal portions of the gastrointestinal tract by the co-administration of Eudragit L100,55. [source] Abstracts: In vitro/in vivo and analytical evaluation of sunless tanning formulations containing different rheology modifiersINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 5 2010O. V. Dueva-Koganov pp. 73,83 In vitro data suggest that different in vivo performances are expected for two dihydroxyacetone (DHA)-containing formulations with similar concentrations of DHA and excipients but different commercially available rheology modifiers: one with a cationic polymer-based rheology modifier (blend) [dimethylacrylamide/ethyltrimonium chloride methacrylate copolymer (and) propylene glycol dicaprylate/dicaprate (and) PPG-1 trideceth-6 (and) C10-11 isoparaffin]; and the other with a polyacrylamide-based rheology modifier (blend) [polyacrylamide (and) C13-14 isoparaffin (and) laureth-7]. Both rheology modifiers (blends) contained comparable levels of polymers and were used at 3% w/w (as supplied). Differences in color development were illustrated in vitro with respect to the yellow/red and lightness/chroma parameters, which were confirmed in the followup in vivo studies. The test article with the cationic polymer-based rheology modifier produced a more natural sunless tan, comparable to a desirable sun-induced tan, for all panelists, one that was more uniform and lasted longer compared with the sunless tan generated by the test article with the polyacrylamide-based rheology modifier. A method for HPLC analysis of DHA in sunless tanning formulations was established and utilized to confirm concentrations of DHA in test articles. [source] Radical annihilation of ,-ray-irradiated contact lens blanks made of a 2-hydroxyethyl methacrylate copolymer at elevated temperaturesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010Young-Shang Lin Abstract The annihilation of the radicals in irradiated 2-hydroxyethyl methacrylate copolymer was analyzed by the use of electron paramagnetic resonance (EPR) spectroscopy. The EPR spectra were deconvoluted into three radicals: a quartet (Ra), a triplet (Rb), and a broad singlet (Rc). Radical Ra was attributed to coupling with a methyl radical and/or a doublet or triplet with about the same hyperfine coupling due to a methylene radical. Radical Rb was due to a methylene radical produced by main-chain scission. Radical Rc was attributed to various free radicals without coupling to protons. By comparing the EPR spectra of radicals Ra, Rb, and Rc with the spectrum of a 2,2-diphenyl-1-picrylhydrazyl (DPPH) standard with a known spin number, we calculated the spin numbers of the radicals, which decreased with time in the temperature range 25,45°C, regardless of the irradiation dose. The annealing of Ra and Rb and the annealing of Rc at longer times followed second-order kinetics; these were different from the kinetics for the color formation and defect-controlled hardening of polymers. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Effect of filler content and size on the properties of ethylene vinyl acetate copolymer,wood fiber compositesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2007D. G. Dikobe Abstract In this study, the main focus was on the effect of wood fiber (WF) content and particle size on the morphology and mechanical, thermal, and water-absorption properties of uncompatibilized and ethylene glycidyl methacrylate copolymer (EGMA) compatibilized ethylene vinyl acetate copolymer,WF composites. For uncompatibilized composites, the tensile strength decreased with increasing WF content, whereas for compatibilized composites, the tensile strength initially decreased, but it increased for composites containing more than 5% WF. Small-WF-particle-containing composites had higher tensile strengths than composites containing larger WF particles, both in the presence and absence of EGMA. WF particle size did not seem to have much influence on the degradation behavior of the composites, whereas water absorption by the composites seemed to be higher in composites with smaller particle sizes for both compatibilized and uncompatibilized composites. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3645,3654, 2007 [source] Sumatriptan succinate transdermal delivery systems for the treatment of migraineJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 6 2008C. Balaguer-Fernández Abstract We have successfully obtained sumatriptan transdermal systems with different polymer compositions: methyl cellulose (MC), polyvinyl pyrrolidone (PVP) and a polyvinyl pyrrolidone (PVP)-polyvinyl alcohol (PVA) mixture. The systems contained 1,2-propilenglycol (MC) or sorbitol as a plasticizer (PVP and PVP-PVA), methacrylate copolymer as an adhesive agent, and an occlusive liner. Azone® (5%, w/w) was incorporated into all the systems as a percutaneous enhancer. Transdermal systems are thin, transparent and non-adhesive when in a dry state. The permeation of sumatriptan succinate across pig ear skin was studied using the systems prepared. The formulation with MC polymer produced a statistically significant increment with respect to the PVP and PVP-PVA formulations (p,<,0.05). Azone® incorporation into the systems produced an increment in the sumatriptan flux values of all three transdermal systems with respect to those of the controls (p,<,0.05). In addition, the application of iontophoresis to the wet methyl cellulose-Azone® formulation produced a much higher increase of sumatriptan transdermal flux. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 97:2102,2109, 2008 [source] Drug,polymer interaction and its significance on the physical stability of nifedipine amorphous dispersion in microparticles of an ammonio methacrylate copolymer and ethylcellulose binary blendJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 1 2008Jingjun Huang Abstract Using spectroscopic and thermal analysis, this study investigated drug,polymer interaction and its significance on the physical stability of drug amorphous dispersion in microparticles of an ammonio polymethacrylate copolymer (Eudragit RL®) (RL) and ethylcellulose (EC) binary blend (RL/EC,=,2:1 w/w) prepared for use in controlled release of poorly water-soluble drugs. Solid dispersion of the model drug, nifedipine in the microparticles could be described as an ideal amorphous mixture for drug loadings up to 11% w/w. The antiplasticizing effect of the polymer blend was indicated by a significant increase in the glass transition point from ,50°C for the amorphous nifedipine to ,115°C for its solid solution. Moreover, shifts in infrared vibration wavenumber of nifedipine carbonyl and amine groups suggested that the hydrogen bonds (H-bonds) originally formed among nifedipine molecules were broken and replaced by those formed between nifedipine and polymers in the microparticles. Further infrared analysis on nifedipine amorphous dispersions with a single polymer, namely RL or EC, confirmed the proposed hydrogen-bonding interactions; and their stability study results suggested that both antiplasticizing effects and hydrogen bonding of EC and RL with nifedipine might be responsible for the physical stability of the microparticles of nifedipine amorphous dispersion with a RL/EC binary blend. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 97:251,262, 2008 [source] Valorization of poly(butylene terephthalate) wastes by blending with virgin polypropylene: Effect of the composition and the compatibilizationPOLYMER ENGINEERING & SCIENCE, Issue 8 2008Najoua Barhoumi Blends of recycled poly(butylene terephthalate) (PBT) parts obtained from scrapped cars, and virgin polypropylene (PP), were prepared in a twin-screw extruder at different compositions. Selected compositions were also prepared with the presence of ethylene- co -glycidyl methacrylate copolymer (E-GMA) and ethylene/methyl acrylate/glycidyl methacrylate terpolymer (E-MA-GMA) compatibilizers. The effect of the composition and the type of compatibilizer, as well as the mixing conditions, on the morphology phase, thermal, viscoelastic behavior, and mechanical properties of the blends has been investigated. Blends PP/PBT of various composition exhibit a coarse morphology and a poor adherence between both phases, resulting in the decrease of ductility, whereas at weak deformation, PBT reinforced the tensile properties of PP. Addition of E-GMA and E-MA-GMA to the PP/PBT blend exhibited a significant change in morphology and improved ductility because of interfacial reactions between PBT end chains and epoxy groups of GMA that generate EG- g -PBT copolymer. Moreover, thermal and viscoelastic study indicated that the miscibility of PP and PBT has been improved further and the reactions were identified. The E-MA-GMA results in the best improvement of ductility. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers [source] Lower critical solution temperature determination of smart, thermosensitive N -isopropylacrylamide- alt -2-hydroxyethyl methacrylate copolymers: Kinetics and physical propertiesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2008Mohammad M. Fares Abstract The lower critical solution temperatures (LCSTs) were verified and determined for different molar feed ratios of N -isopropylacrylamide (NIPAAm) and 2-hydroxyethyl methacrylate (HEMA) monomers with ultraviolet spectroscopy and differential scanning calorimetry techniques. Increases in the NIPAAm monomer content played a crucial role in the LCST, which increased up to 36.7°C at 50 mol %. However, a further increase in the NIPAAm monomer content steadily reduced the LCST, which decreased to 33°C at 100 mol % NIPAAm [i.e., pure poly(N -isopropylacrylamide)]. The rate of copolymerization, assessed by the conventional conversion (%),time method, and the apparent activation energies were determined. The reactivity ratios of the monomers, determined by the Kelen,Tudos and Fineman,Ross techniques, together with the results of an equation, showed that the copolymer which formed was an alternating copolymer. The Q,e values for the NIPAAm monomer were determined. The equation showed the linear Arrhenius behavior of ln(r1r2) versus the reciprocal of the temperature (where r1 and r2 are the reactivity ratios of NIPAAm and HEMA, respectively): the activation energy difference [i.e., (E12 + E21) , (E11 + E22), where E12, E21, E11, and E22 are various activation energies] was found to be ,109 kJ/mol. The copolymers were characterized with 1H-NMR, 13C-NMR, Fourier transform infrared, ultraviolet,visible, thermogravimetric analysis, differential scanning calorimetry, X-ray diffraction, and scanning electron microscopy techniques. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Synthesis, characterization, and antimicrobial properties of novel quaternary amine methacrylate copolymersJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2008Supriya Punyani Abstract A novel amine methacrylate monomer trimethylolpropane trimethacrylate,piperazine,ethyleneglycol dimethacrylate (TMPTMA-PPZ-EGDMA) was synthesized by amination of trimethylolpropane trimethacrylate (TMPTMA) with excess of piperazine (PPZ) followed by reaction with ethyleneglycol dimethacrylate (EGDMA). Copolymerization of TMPTMA-PPZ-EGDMA with 2-hydroxyethyl methacrylate (HEMA) was carried out by free radical polymerization using ammonium persulfate (APS) and N,N,N,,N,-tetramethyl ethylenediamine (TEMED) as a redox initiator. The copolymers obtained were then quaternized with 1-iodooctane. The monomers were characterized by FTIR and 1H NMR spectral studies. The molecular weights and polydispersity values of the monomers were determined with gel permeation chromatography. Quaternized copolymers containing more than 20% amine methacrylate monomer showed microporosity in the range of 9.9,10.4 ,m. The antibacterial activity of the quaternized copolymers against Escherichia coli and Staphylococcus aureus was studied using UV,vis spectrophotometer and scanning electron microscopy. Quaternized copolymers showed broad-spectrum contact-killing antibacterial properties without releasing any active agent as checked by iodide selective ion meter. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Comprehensive 2-D chromatography of random and block methacrylate copolymersJOURNAL OF SEPARATION SCIENCE, JSS, Issue 10 2010Monique van Hulst Abstract A comprehensive 2-D separation method was developed for the characterization of methacrylate copolymers. In both dimensions conditions were employed that give a critical separation for the homopolymer of one of the monomers in the copolymer, and exclusion behaviour for the other. The 2-D separation was realized by using a normal-phase column in one dimension and a reversed phase column in the other, and by precisely tuning the compositions of the two mobile phases employed. In the normal-phase dimension mixtures of THF and n -hexane or n -heptane were used as mobile phase, and in the reversed-phase dimension mixtures of ACN and THF. Moreover, stationary phase particles had to be selected for both columns that gave an exclusion window appropriate for the molecular size of the sample polymers to be characterized. The 2-D critical chromatography principle was tested with a polystyrene (PS)-polymethylmethacrylate (PMMA) block copolymer and with block and random polybutylmethacrylate (PBMA)-PMMA copolymers. Ideally, the retention time for a copolymer in both dimensions of this system would depend on the size of only one of the blocks, or on the contribution of only one of the monomers to the size of a random copolymer. However, it was found that the elution of the PS-PMMA block copolymer depended on the size of both blocks, even when the corresponding homopolymer of one of the monomers showed critical elution behaviour. Therefore, the method could not be calibrated for block sizes by using homopolymer standards alone. Still, it was shown that the method can be used to determine differences between samples (PS-PMMA and PBMA-PMMA) with respect to total molecular size or block sizes separately, or to average size and chemical composition for random copolymers. Block and random PBMA-PMMA copolymers showed a distinctly different pattern in the 2-D plots obtained with 2-D critical chromatography. This difference was shown to be related to the different procedures followed in the polymerization process, and the different molecular distributions resulting from these. [source] Cloud-Point Pressure Curves of Ethene/Poly[ethylene- co -((meth)acrylic acid)] MixturesMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 4 2003Michael Buback Abstract Ethene-methacrylic acid (MAA) and ethene-acrylic acid (AA) copolymers of narrow polydispersity and high chemical homogeneity have been synthesized at acid unit copolymer contents up to 9 mol-% within a continuously operated stirred tank reactor at overall monomer conversions of about 2%. Cloud-point pressures (CPPs) of mixtures of 3 wt.-% copolymer in ethene (E) have been measured in an optical high-pressure cell at pressures and temperatures up to 3,000 bar and 260,°C, respectively. The CPP weakly increases with acid copolymer content up to about 3.5 mol-%. Toward higher acid contents, the CPP is strongly enhanced, in particular at the lower edge of the experimental temperature range at around 200,°C. This increase in CPP is more pronounced for the AA than for the MAA systems. The data suggest that hydrogen-bonding interactions are operative in the pressurized E/poly(E- co -(M)AA) mixtures at temperatures of 260,°C and perhaps even above. E-AA and E-MAA copolymers with acid contents of about 5.6 mol-% have also been completely methyl-esterified to yield the associated methyl esters. The CPPs of the resulting E-methyl acrylate and E-methyl methacrylate copolymers in mixtures with E are significantly below the CPPs of the corresponding E/poly(E- co -(M)AA) systems. Cloud-point pressure vs temperature curves for several E/poly(E- co -methacrylic acid) systems. The subscripts denote copolymer content in mol-%. A cloud-point pressure curve for E/polyethylene (PE) is included for comparison. [source] Solid-state structure and formation of organized molecular films of methacrylate copolymers containing fluorinated and hydrogenated side-chainsPOLYMER ENGINEERING & SCIENCE, Issue 4 2007Atsuhiro Fujimori Surface morphology of monolayers related to solid-state structure for methacrylate comb copolymers having fluorocarbon and hydrocarbon side-chains was investigated by X-ray diffraction (XRD), differential scanning calorimetry, and atomic force microscopy (AFM). From the XRD profiles, two kinds of short spacing peaks were confirmed at 5.0 and 4.2 Ĺ, which assigned the sub-cells for both side-chains. Furthermore, two kinds of endothermic peaks, which corresponded to melting peaks of the both side-chain crystals, appeared in the thermograms. From the AFM observation, it was found that there were hydrogenated domains at a few hundred nanometer diameter in their monolayers, whereas corresponding acrylate copolymer monolayers form the phase-separated structure at 10,30 nm order scales. POLYM. ENG. SCI., 47:354,364, 2007. © 2007 Society of Plastics Engineers. [source] | ||||||||||||||||