Methyl Vinyl Ether-maleic Anhydride Research Articles

Slow-release indomethacin formulations based on polysaccharides: evaluation in vitro and in vivo in dogs

A series of sustained release formulations for the potent anti-inflammatory drug indomethacin were prepared by dispersing indomethacin in polysaccharide matrixes to form small microspheres. The matrixes comprised insoluble polycationic salts of polysaccharides such as, polygalacturonic acid, alginate, or carboxymethyl cellulose salts or Gantrezan (a copolymer of methyl vinyl ether maleic anhydride). The influence of the type of cation used to prepare the polymer salts and the type of polymer on the release rate of indomethacin from the microspheres was tested in vitro, and some formulations were examined in vivo in dogs. The pH of the medium was found to have a considerable influence on the in vitro release rate, the rate at pH 7.2 being much faster than that at pH 6.2 or 1.5. In vivo tests in mongrel dogs showed a big difference in plasma levels among the dogs, while the highest plasma levels were obtained after administration of the nonformulated product. Statistical treatment of the pharmacokinetic data for nonformulated and the formulated products showed no differences in T max , t 1 2 , k el, AUC and MRT. C ma obtained from the Ca-polygalacturonic acid salt formulation and the commercial product Indocin S.R. (Merck) were statistically significantly lower than the values of the non-formulated product. Since it is likely that this reduction would result in a lessening of side effects, we propose that our indomethacin formulation based on Ca-polygalacturonic acid salt would be suitable for further testing in human volunteers.

Investigation of surface properties of some polymers by a thermodynamic and mechanical approach: possibility of predicting mucoadhesion and biocompatibility

Mucoadhesive properties of several polymers, such as sodium alginate, hydroxypropylmethyl cellulose, scleroglucan, xanthan gum, polyacrylic acid (Carbopol ®), and poly co-(methyl vinyl ethermaleic anhydride) (Gantrez ®), have been investigated by comparing a thermodynamical and a mechanical approach. Surface properties of polymers in the dry state have been studied by contact angle measurements and thermodynamical parameters derived by using different equations. This tensile adhesive strength of polymers in hydration conditions was measured by a modified DuNoy tensiometer. Comparison of the two different approaches has allowed us to conclude that thermodynamical consideration on surface energy can be used to evaluate mucoadhesive properties of materials. Data obtained with the two methods yielded a good linear correlation. Calculation of surface free energy of the considered materials also allowed a prediction of the water-polymer interface free energy: biocompatibility, defined according to the minimal interfacial free energy concept, could consequently be evaluated.

Immobilization of protein ligands with methyl vinyl ether-maleic anhydride copolymer

Methyl vinyl ether-maleic anhydride copolymer (MMAC) is a water-insoluble polymer with an acid anhydride group which reacts with amino groups of ligands to form stable amide bonds. MMAC was used to immobilize protein ligands on two kinds of supports, the wells of plastic microtitre plates for enzyme-linked immunosorbent assay and related methods, and gels for affinity adsorbents. The wells were first coated with MMAC and then allowed to react with proteins. The immobilization of proteins by this method was efficient and occurred in a dose-dependent manner. Shodex Et123, a gel having amino groups, was incubated with MMAC, and then the activated Shodex was used to immobilize high concentrations of proteins. Concanavalin A-Shodex thus obtained had high affinities and was successfully used for the high-performance liquid affinity chromatography of sugar derivatives on a short column.

Configurational statistics of methyl vinyl ether-maleic anhydride copolymer: selection of important atomic interactions and conformations

Average dimensions of the unperturbed copolymer chain are calculated by using the rotational isomeric state model. The relative energy of each rotational isomer has been approximated three ways: 1) by analogy to known atomic interactions as reported for small molecules and derived from polymer properties; 2) by computation of atomic interaction energies with the MM2 molecular mechanics program, and 3) by calculation of the relative energy of each conformation of the entire subunit using MM2. The characteristic ratio, 0 /nl 2 , at the limit of large n, is calculated separately for each of the four most important steroisomers and compared to the experimental characteristic ratio

The adhesive properties of hydantoin vinyl ether polymers

AbstractThe hydantion vinyl ether polymers are alternating copolymers of 3‐vinyloxyethyl‐5,5‐dimethylhydantion (HVE) and maleic anhydride (MA). The adhesive properties of HVE/MA and structurally related polyvinyl pyrrolidone (PVP) and methylvinylether/maleic anhydride (MVE/MA) polymers were compared on an approximately 1:1 specific viscosity basis. Lap shear strength measurements showed approximately 10:1 and 4:1 ratios in favor of the HVE/MA polymers as compared to PVP and MVE/MA, respectively. These differences are possibly due to the higher cohesive strength of the HVE/MA repeating unit and to the fact that this polymer would appear to contain more structural elements liable to make physical and chemical contributions to the interfacial attachment strength. Based on these preliminary results, HVE/MA and MVE/MA polymers with identical specific viscosities were applied to carbon pitch fiber via electrodeposition. Using the standard MY 720/DDS epoxy laminating system for advanced composite applications 36% and 13% improvements in interlaminar shear strength were observed for an add‐on of 2%.

Orientation of monolayers of half-esters of poly(methyl vinyl ether maleic anhydride)

Abstract The effects of subphase pH and certain water-soluble plasticizers on the surface pressure (π)-area (A) isotherms of monolayers of the ethyl and hexyl half-esters of poly (methyl vinyl ether/maleic anhydride) ( PVM MA ) were investigated. An increase in subphase pH (above pH 3.9) causes a decrease in the surface area of the ethyl half-ester monolayer at constant surface pressure but the π-A curve of the monolayer of the hexyl half-ester undergoes little change over a pH range of 3.0 to 6.7. Films of both PVM MA half-esters were found to interact with water-soluble plasticizers. When the plasticizers are compared at the same initial surface pressure, the degree of penetration of monolayers of the ethyl half-ester of PVM MA is practically the same. However, dibutyl phthalate penetrates the hexyl half-ester to a greater extent than does dibutyl adipate or succinate. Based on the results of these experiments, inferences are drawn as to polymer orientation at the air-water interface.