Search results for "Polyacrylic acid"
showing 10 items of 11 documents
Uranium(VI) sequestration by polyacrylic and fulvic acids in aqueous solution
2011
Stability data on the formation of dioxouranium(VI) species with polyacrylic (PAA) and fulvic acids (FA) are reported with the aim to define quantitatively the sequestering capacity of these high molecular weight synthetic and naturally occurring ligands toward uranium(VI), in aqueous solution. Investigations were carried out at t = 25 °C in NaCl medium at different ionic strengths and in absence of supporting electrolyte for uranyl–fulvate (\( {{\text{UO}}_{2}}^{2+} \)–FA) and uranyl–polyacrylate (\( {{\text{UO}}_{ 2}}^{ 2+ } \)–PAA, PAA MW 2 kDa) systems, respectively. The experimental data are consistent with the following speciation models for the two systems investigated: (i) UO2(FA1),…
Transbuccal tablets of carbamazepine: formulation, release and absorption pattern.
2006
Tranbsuccal drug administration is an attractive method, as it has several advantages especially with respect to peroral delivery. Here we report: i) the aptitude of carbamazepine (CBZ) to penetrate porcine buccal mucosa and reconstituted human oral (RHO) epithelium; ii) three different tablet formulations for transbuccal administration; iii) the drug release rate from tablets. CBZ permeation through the buccal mucosa was investigated by using two different bi-compartmental open models: Franz cells for porcine buccal mucosa and Transwell diffusion cells system for RHO epithelium. Results, expressed as drug flux (Js) and permeability coefficients (Kp), indicated that CBZ well penetrates the …
Synergistic behavior of poly(aspartic acid) and Pluronic F127 in aqueous solution as studied by viscometry and dynamic light scattering.
2012
Abstract Pluronic F127/poly(aspartic acid) mixtures were investigated in dilute solutions by viscometry and dynamic light scattering. The two polymers were chosen due to well known applications in biomedical field, taking into account the final purpose (the use of the complex structure as drug delivery systems). The central item was to identify the possibility of complexation between the poly(carboxylic acid) and a non-ionic polymer and to investigate the conditions of the interpolymer complex formation. The ability of Pluronic F127 to form micelle is well known. Poly(aspartic acid), as a polycarboxylic acid with resemblance with polyacrylic acid, can act as dispersant, antiscalant, superab…
Inulin-iron complexes: a potential treatment of iron deficiency anaemia.
2007
The aim of this work was that to synthesize macromolecular derivatives based on inulin able to complex iron and useful in the treatment of iron deficiency anaemia. Carboxylated or thiolated/carboxylated inulin derivatives were obtained by single or double step reactions, respectively. The first one was obtained by reaction of inulin (INU) with succinic anhydride (SA) alone obtaining INU-SA derivative; the second one was obtained by the reaction of INU with succinic anhydride and subsequent reaction of INU-SA with cysteine; both derivatives were treated with ferric chloride in order to obtain the INU-SA-Fe(III) and INU-SA-Cys-Fe(III) complexes. Both complexes showed an excellent biodegradabi…
Effect of media composition on long-term in vitro stability of barium alginate and polyacrylic acid multilayer microcapsules.
2000
For a number of applications stability of microcapsules is a critical factor. Since the maintenance of polyelectrolyte complexes depends considerably on the ion composition we tested the physical properties of barium alginate capsules and searched for conditions to improve stability by a multilayer coating with polyethylenimine (PEI) and polyacrylic acid (PAA). Mechanical stability and diameters were determined in barium alginate capsules and compared with multilayer capsules. Multilayer coating resulted in smaller capsules than barium complexing alone. The difference was more pronounced when CaCl2 was used instead of NaCl during coating. Barium alginate capsules and application of CaCl2 du…
The effect of dentine pre-treatment using bioglass and/or polyacrylic acid on the interfacial characteristics of resin-modified glass ionomer cements.
2018
Objective To evaluate the effect of load-cycle aging and/or 6 months artificial saliva (AS) storage on bond durability and interfacial ultramorphology of resin-modified glass ionomer cement (RMGIC) applied to dentine air-abraded using Bioglass 45S5 (BAG) with/without polyacrylic acid (PAA) conditioning.Methods RMGIC (Ionolux, VOCO) was applied onto human dentine specimens prepared with silicon-carbide abrasive paper or air-abraded with BAG with or without the use of PAA conditioning. Half of bonded-teeth were submitted to load cycling (150,000 cycles) and half immersed in deionised water for 24 h. They were cut into matchsticks and submitted immediately to microtensile bond strength (μTBS) …
Consistency of Carbopol 971-P NF gels and influence of soluble and cross-linked PVP.
2002
A study is made of the polymerization process of polyacrylic acid, commercially known as Carbopol® 971 NF, assessing its consistency as a function of the degree of neutralization at pH values from 3 to 12, approximately. Percentage concentrations ranging from 0.1 to 1.4% (w/w) were studied. The gels obtained were non-Newtonian, and pseudoplastic. As concentration and pH rise, the consistency of the gels increase to a maximum, which appears between pH 6 and 8, allowing their use as vehicles in bioadhesive formulations for mucosal application. Over the increasing viscosity interval, functions were obtained to indicate the consistency of the gel as a function of pH and concentration. Since the…
Versuche über die oxydation von polyacroleinen mit wasserstoffperoxyd und peressigsäure. Polymer acroleine. 8. Mitt.
1958
Polyacroleine werden durch verdunntes Wasserstoffperoxyd vollstandig abgebaut. Als Abbauprodukte konnten Kohlendioxyd, Ameisensaure und Essigsaure identifiziert werden. Daneben bilden sich noch unbekannte nicht-fluchtige Saren. Polyacrylsaure erleidet unter den gleichen Bedingungen ebenfalls einen Abbau. Die Zusammensetzung der Abbauprodukte ist eine andere. Durch Peressigsaure werden Polyacroleine zu polymeren Sauren oxydiert. Diese gleichen bezuglich der Loslichkeit, der Reaktionen mit Schwermetallsalzen und dem IR- Spektrum weitgehend der Polyacrylsaure. Polyacroleins are completely degraded by the action of dilute hydrogen peroxide. Among the products of degradation carbon dioxyde, form…
Binding of acrylic and sulphonic polyanions by open-chain polyammonium cations
2000
Abstract The interactions between some acrylic and sulphonic polyanions and some protonated amines (diamines NH 2 -(CH 2 ) x -NH 2 , x =2,…,10; linear tri-, tetra-, penta- and hexa-amines) were studied potentiometrically in aqueous solution, at 25°C. For both types of polyanions AL 2 H i (L − , monomer of polyanion, A, amine) species are formed, with i =1,…, n ( n =number of amino groups in the amine). The stability of these species is strictly dependent on the polyammonium cation charge, and fairly independent of the type of amine (in diamine species maximum stability is observed for x =4, 5). Acrylic and sulphonic polyanion complexes are considerably stronger than analogous species formed…
Effects of Polyacrylic Acid Pre-Treatment on Bonded-Dentine Interfaces Created with a Modern Bioactive Resin-Modified Glass Ionomer Cement and Subjec…
2018
Objectives: Resin-modified glass ionomer cements (RMGIC) are considered excellent restorative materials with unique therapeutic and anti-cariogenic activity. However, concerns exist regarding the use of polyacrylic acid as a dentine conditioner as it may influence the bonding performance of RMGIC. The aim of this study was to evaluate the effect of different protocols for cycling mechanical stress on the bond durability and interfacial ultramorphology of a modern RMGIC applied to dentine pre-treated with/without polyacrylic acid conditioner (PAA). Methods: The RMGIC was applied onto human dentine specimens prepared with silicon-carbide (SiC) abrasive paper with or without the use of a PAA c…