Methacrylate-type copolymers

Dispersingagents, such as polyethylene polyamide succinimides or methacrylate-type copolymers, are added to motor oils to disperse low-temperature sludge formed in spark-ignition engines. 

These were obtained by copolymerization of styrenic macromonomers containing dendritic pendant groups with styrene [16a] with a later extension to methacrylate-type copolymers [16b]. As these studies were carried out with... 

Classification of polymeric adsorbents according to the geometrical structure (Table 1) is based on concepts acceptable for traditional adsorbents. The structure is regarded as macroporous if the pore diameter d>100 nm, mesoporous if d=3-100 nm and microporous if d<3 nm (ref.3). As evident, methacrylate-type copolymers are mesoporous adsorbents, but under certain synthesis conditions macroporous samples can also be obtained. ST-DVB copolymers have a mesoporous structure, but they have generally few microporous due to parallel DVB-DVB... 

N, N, iV-trimethyl-lV-methacrylamido-2-ethylammonium chloride (salt V), can be compared with networks copolymerized with salt I. For the system AAm/ salt V, one can expect more favourable copolymerization parameters than for salt I of the methacrylate type, which will lead to a more random structure of the copolymer formed. 

For the styrene-butadiene-methacrylic acid copolymers, meth-acrylic acid was also found in the serum, on the particle surface, and buried inside the particles. At 23% degree of neutralization, less methacrylic acid was found in the serum and on the particle surface than with acrylic acid, i.e., more was buried inside the particle. At 3.0% methacrylic acid, the amount incorporated into the particle was fairly constant, independent of the degree of neutralization. The different distributions of methacrylic and acrylic acids were explained by their different distributions between the monomer-polymer and aqueous phases. Thus these characterization results show the effect of vinyl carboxylic acid type and concentration on the loci of the carboxyl groups. Similar correlations could be made with other systems. 

To achieve enteric protection of the core, at least 3-4 mg/cm2 of polymer have to be applied (Figure 4). The precise amount of film coating depends on the type of polymer that is applied. Cellulose derivatives usually require higher amounts of polymer to obtain the same protection as methacrylic acid copolymers. A thin layer of 4 mg/cm2 of methacrylate copolymer will dissolve within approximately 10 minutes. However, if increasing layers of polymer are applied, the dissolution time will be prolonged, which can be used to delay the dissolution of the dmg in the small intestine (Figure 5). 

The enteric protection properties of a methacrylate polymer were investigated with the use of naproxen tablets [56] enteric coated with an aqueous dispersion of methacrylic acid copolymer (EUDRAGIT L 30 D-55, USP NF type C). 

As previously discussed, food effects are an important parameter for enteric-coated systems, especially for drugs, that are sensitive to food. Pancreatic enzyme-containing products fail when they come in contact too early with lipids, proteins, and carbohydrates present in food. The clinical efficacy of pancreatic enzymes formulated as enteric-coated tablets was investigated in man and dog [44], The enteric materials examined were hydroxypropyl methylcellulose phthal-ate (HPMCP), cellulose acetate phthalate (CAP), and the methacrylic acid copolymer USP/NF Type C. In vivo behavior monitored by x-ray scintigraphy showed clear differences between the three coating formulations. HPMCP-coated products adhered to the gastric mucosa, whereas CAP and methacrylate copolymer... 

CGP 57813 is a peptidomimetic inhibitor of human HIV-1 protease. This lipophilic compound has been successfully entrapped in polylactic acid (PLA) and into pH-sensitive methacrylic acid copolymer particles (EUDRAGIT L 1 GO-55) [69], After the application of a film-coating, the plasma concentration was acceptable and reached similar levels as with injections of drug-loaded PLA carriers. To hinder the proteolytic degradation of a drug, two types of enteric-coated pellets were applied simultaneously. One contained the protease inhibitor coated... 

W. A. Habib, A. Sakr, Effect of methacrylic acid copolymer USP/NF type C and the release of polypeptide drug nisin, AAPS, Annual Congress Boston, November 1997. 

In the area of hydrometallurgy, Cu2+ and Au(CN)2 salts could be selectively sorbed from aqueous solutions with polyacrylamide-based copolymers containg aminoguanidine units. Porous copolymers of acrylonitrile, divinylbenzene and vinylacetate were derivated with aminoguanidine.15 Alternatively, methacrylate-based copolymers were transamidated with the same base16 to give polyacrylamide-type resins (Figure 11). 

Methacrylic acid copolymer Methacrylic acid copolymer dispersion Note that three separate monographs applicable to polymethacrylates are contained in the USPNF 23 see Section 9. Several different types of material are defined in the monographs. The PhEur 2005 contains four separate monographs applicable to polymethacrylates. 

The USPNF 23 describes methacrylic acid copolymer as a fully polymerized copolymer of methacrylic acid and an acrylic or methacrylic ester. Three types of copolymers, namely Type A, Type B, and Type C, are defined in the monograph. They vary in their methacrylic acid content and solution viscosity. Type C may contain suitable surface-active agents. Two additional polymers, Type A (Eudragit RE) and Type B (Eudragit RS), also referred to as ammonio methacrylate copolymers, consisting of fully polymerized copolymers of acrylic and methacrylic acid esters with a low content of quaternary ammonium groups, are also described in the USPNF 23. A further monograph for an aqueous dispersion of Type C methacrylic acid copolymer is also defined see Section 9. 

Eastacryl30D, Kollicoat MAE 30 D, and KollicoatMAE 30 DP are also aqueous dispersions of the anionic copolymer based on methacrylic acid and ethyl acrylate. The copolymer also corresponds to USPNF 23 methacrylic acid copolymer. Type C. The ratio of free-carboxyl groups to ester groups is 1 1. Films prepared from the copolymers dissolve above pH... 

With a proper choice of mobile phase (aqueous or nonaqueous), many commercially columns are available for SEC of PVP and VP-based copolymers. Mobile-phase modifiers (such as methanol, salt, and buffer) are normally required to eliminate interactions with columns. A single linear or mixed-bed column has been found to provide good separation of PVP and VP-based copolymers with a molecular weight range of from a few thousands to several millions. In general, the aqueous SEC system has better long-term stability and provides better separation than the nonaqueous SEC system, especially at the low-molecular-weight end. Hydroxylated methyl-methacrylate-type columns and water-methanol mobile phase (50 ... 

The enteric materials examined were hydroxypropyl methylcellulose phthal-ate (HPMCP), cellulose acetate phthalate (CAP), and the methacrylic acid copolymer USP/NF Type C. In vivo behavior monitored by x-ray scintigraphy showed clear differences between the three coating formulations. HPMCP-coated products adhered to the gastric mucosa, whereas CAP and methacrylate copolymer... 

AB and ABA type acrylate/methacrylate block copolymers can also be prepared by ATRP using a sequential addition of monomers technique, resulting in a well-defined central block and an outer block composed of a mixture of the... 

The order of monomer addition is important. For example, to prepare an AB type block copolymer of styrene and methyl methacrylate, st ene must be polymerized first using a monofunctional initiator and when styrene is completely reacted, the other monomer MMA must be added. The copolymer would not form if MMA were polymerized first, because living poly(methyl methacrylate) is not basic enough to add to styrene. The length of each block is determined by the amount of corresponding monomer which was provided. To produce ABA type copolymer by monofunctional initiation, B can be added when A is consumed, and A added again when B is consumed. This procedure is possible if the anion of each monomer sequence can initiate polymerization of the other monomer. Multiblock copolymers can also be made in this way. 

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