Methacrylic acid

About: Methacrylic acid is a research topic. Over the lifetime, 13058 publications have been published within this topic receiving 173201 citations. The topic is also known as: α-Methacrylic acid & 2-Methylacrylic acid.

Swelling behavior and release properties of pH-sensitive hydrogels based on methacrylic derivatives

Abstract: The purpose of this study is to develop novel intestinal- -specific drug delivery systems with pH sensitive swelling and drug release properties. Methacrylic-type polymeric prodrugs were synthesized by free radical copolymeriza- tion of methacrylic acid, poly(ethyleneglycol monomethyl ether methacrylate) and a methacrylic derivative of N-(4- -hydroxyphenyl)-2-(4-methoxyphenyl) acetamide in the presence of ethylene glycol dimethacrylate as crosslink- ing agent. The effect of copolymer composition on the swelling behavior and hydrolytic degradation were stu- died in simulated gastric (SGF, pH 1.2) and intestinal flu- ids (SIF, pH 7.0). The dynamic swelling behavior of these hydrogels was investigated to determine the mechanism of water transport through these hydrogels. The mecha- nism of water transport through the gels was significant- ly affected by the pH of the swelling medium and beca- me more relaxation-controlled in a swelling medium of pH 7.0. The swelling and hydrolytic behaviors of hydro- gels were dependent on the content of methacrylic acid (MAA) groups and caused a decrease and increase in gel swelling in SGF and SIF, respectively. Drug release studi- es showed that the increasing content of MAA in the co- polymer enhances hydrolysis in SIF. These results suggest that pH-sensitive systems could be useful for preparati- on of a muccoadhesive system and controlled release of N-(4-hydroxyphenyl)-2-(4-methoxyphenyl) acetamide.

Hybrids of Magnetic Nanoparticles with Double‐Hydrophilic Core/Shell Cylindrical Polymer Brushes and Their Alignment in a Magnetic Field

Abstract: The synthesis of double-hydrophilic core/shell cylindrical polymer brushes (CPBs), their hybrids with magnetite nanoparticles, and the directed alignment of these magnetic hybrid cylinders by a magnetic field are demonstrated. Consecutive grafting from a polyinitiator poly(2-(2-bromoisobutyryloxy)ethyl methacrylate) (PBIEM) of tert-butyl methacrylate (tBMA) and oligo(ethylene glycol) methacrylate (OEGMA) using atom-transfer radical polymerization (ATRP) and further de-protection yields core/shell CPBs with poly(methacrylic acid) (PMAA) as the core and POEGMA as the shell, which is evidenced by 1 H NMR, gel permeation chromatography (GPC), and dynamic and static light scattering (DLS and SLS). The resulting core/shell brush is well soluble in water and shows a pH responsiveness because of its weak polyelectrolyte core. Pearl-necklace structures are observed by cryogenic transmission electron microscopy (cryo-TEM) at pH 4, while at pH 7, these structures disappear owing to the ionization of the core. A similar morphology is also found for the polychelate ofthe core/shell CPBs with Fe 3+ ions. Superparamagnetic magnetite nanoparticles have also been prepared and introduced into the core of the brushes. The hybrid material retains the superparamagnetic property of the magnetite nanoparticles, which is verified by superconducting quantum interference device (SQUID) magnetization measurements. Large-scale alignment of the hybrid cylinders in relatively low magnetic fields (40-300 mT) can easily be performed when deposited on a surface. which is clearly revealed by the atomic force microscopy (AFM) and TEM measurements.

NMR Studies of the Structure and Dynamics of Polymer Gels Based on N-Isopropylacrylamide (NiPAAm) and Methacrylic Acid (MAA)

Abstract: A series of copolymer gels and interpenetrating networks (IPN) based on N-isopropylacrylamide (NiPAAm) and methacrylic acid (MAA) were synthesized and subsequently investigated by magic angle spinning 1H MAS, cross polarization 13C CP-MAS and pulse-saturation transfer 13C PST-MAS NMR. The structure of the interpenetrating networks is compared to that of the copolymer gels with the same composition. The study of the proton lines reveals low mobility of the chains in the copolymer gels and IPN with higher concentration of MAA, whereas those which are predominantly N iPAAm show higher mobility and therefore narrower proton lines. 13C CP-MAS revealed an interaction between the components of the IPNs. The PST-MAS technique was utilized to study the structure of the polymers in the gel phase. Copolymer gels exhibit some additional peaks in the carbonyl region due to the new chemical environment in the stereoregular sequences. In order to assure assignment, uncrosslinked copolymers with similar compositions as the copolymer gels were synthesized for comparative purposes and examined by conventional solution-state 13C NMR. A linear homopolymer of N iPAAm was synthesized inside of a P(MAA) gel. The polymer was extracted after the completion of the reaction and characterized by solution 13C NMR. About 24% of this P(N iPAAm) homopolymer could not be extracted presumably because of a strong hydrogen bonding or partial topological constrains. In the 13C NMR spectrum a new signal appeared in the carbonyl region due to MAA monomeric units. It may correspond to the methacrylic carbonyls interacting by hydrogen bonds with the amide groups.