The Experts below are selected from a list of 60 Experts worldwide ranked by ideXlab platform

Insup Noh - One of the best experts on this subject based on the ideXlab platform.

Reena Singhal - One of the best experts on this subject based on the ideXlab platform.

  • a study on Copolymeric Hydrogels based on acrylamide methacrylate and its modified vinyl amine containing derivative
    Designed Monomers and Polymers, 2004
    Co-Authors: Tamanna Begam, A K Nagpal, Reena Singhal
    Abstract:

    Acrylamide-co-methyl methylacrylate (AAm-co-MMA) Copolymeric Hydrogels of different ratios were prepared by using chemical and physical crosslinks. The physically crosslinked Hydrogels were prepared by solution polymerization using benzoyl peroxide as an initiator, while the chemically crosslinked Hydrogels were prepared by using N,N'-methylene bisacrylamide (N,N'-MBA) as crosslinking agent. This Copolymeric Hydrogel was further modified by Hofmann degradation to improve its swelling behaviour. 1 H-nuclear magnetic resonance ( 1 H-NMR), Fourier transform infra-red spectroscopy (FT-IR), differential scanning calorimetry (DSC) and elemental analysis have been used to characterize the Copolymeric gel. Elemental analysis has been used to evaluate the copolymer composition. The influence of environmental conditions such as temperature and pH value on the swelling behaviour of these Copolymeric gels was investigated. Results showed that the Hydrogels exhibited different equilibrium swelling ratios at different pH and temperature of swelling medium. The temperature and pH sensitivities of these gels also depended on the AAm content in the Copolymeric Hydrogels. These Hydrogels exhibited 2135% swelling at 60°C, which was reversible and very good dimensional stability was mentioned. This was due to hydrolysis of amide groups could be hydrolyzed to form negatively charged carboxylate ion in Hydrogels in response to an external pH and temperature variation.

Dipankar Das - One of the best experts on this subject based on the ideXlab platform.

Tamanna Begam - One of the best experts on this subject based on the ideXlab platform.

  • a study on Copolymeric Hydrogels based on acrylamide methacrylate and its modified vinyl amine containing derivative
    Designed Monomers and Polymers, 2004
    Co-Authors: Tamanna Begam, A K Nagpal, Reena Singhal
    Abstract:

    Acrylamide-co-methyl methylacrylate (AAm-co-MMA) Copolymeric Hydrogels of different ratios were prepared by using chemical and physical crosslinks. The physically crosslinked Hydrogels were prepared by solution polymerization using benzoyl peroxide as an initiator, while the chemically crosslinked Hydrogels were prepared by using N,N'-methylene bisacrylamide (N,N'-MBA) as crosslinking agent. This Copolymeric Hydrogel was further modified by Hofmann degradation to improve its swelling behaviour. 1 H-nuclear magnetic resonance ( 1 H-NMR), Fourier transform infra-red spectroscopy (FT-IR), differential scanning calorimetry (DSC) and elemental analysis have been used to characterize the Copolymeric gel. Elemental analysis has been used to evaluate the copolymer composition. The influence of environmental conditions such as temperature and pH value on the swelling behaviour of these Copolymeric gels was investigated. Results showed that the Hydrogels exhibited different equilibrium swelling ratios at different pH and temperature of swelling medium. The temperature and pH sensitivities of these gels also depended on the AAm content in the Copolymeric Hydrogels. These Hydrogels exhibited 2135% swelling at 60°C, which was reversible and very good dimensional stability was mentioned. This was due to hydrolysis of amide groups could be hydrolyzed to form negatively charged carboxylate ion in Hydrogels in response to an external pH and temperature variation.

Malcolm B Huglin - One of the best experts on this subject based on the ideXlab platform.

  • drug release with simultaneous dimensional changes from a new Copolymeric Hydrogel
    Polymer, 1994
    Co-Authors: Maria D Blanco, Josem Rego, Malcolm B Huglin
    Abstract:

    Abstract The diffusional behaviour of sodium salicylate (SSA) from a new chemically crosslinked Copolymeric Hydrogel of 2-hydroxyethyl methacrylate with N,N′-dimethyl-N-methacryloyloxyethyl-N-(3-sulfopropyl)ammonium betaine is reported. The drug release into water was effected under sink conditions and the kinetics at 310 K were followed by continuous measurement of conductivity. A modified form of Fick's second law has been derived to take into account the dimensional changes of copolymer during drug release, which were measured photographically. The procedure was used to evaluate the diffusion coefficient Ds for transport of SSA into water. The value of Ds = 4.4 × 10−11 m2 s−1 yielded over a range of drug loading is smaller than the load-dependent values obtained when allowance is not made for dimensional changes. The procedure has also been used to determine the diffusion coefficient for water into polymer.