Controlled release systems macromolecules

Robert Langer, Polymer Systems for Controlled Release of Macromolecules, Immobilized Enzyme Medical Bioreactors, and Tissue Engineering J. J. Linderman, P. A. Mahama, K. E. Forsten, and D, A. Lauffenburger, Diffusion and Probability in Receptor Binding and Signaling Rakesh K. Jain, Transport Phenomena in Tumors... 

Langer, R. 1994. Polymer systems for controlled release of macromolecules, immobilized enzyme medical bioreactors, and tissue engineering. In Advances in Chemical Engineering, vol. 19. San Diego, CA Academic Press 1-50. 

Robert Langer, Polymer Systems for Controlled Release of Macromolecules, Immobilized Enzyme Medical Bioreactors, and Tissue Engineering... 

The controlled release of macromolecules from non-erodible, hydrophobic polymeric matrices is modelled as a discrete diffusion process with the release of solute occuring through distinct pores in the polymer which are formed as solid particles of molecule dissolve. In order to formulate predictive models of the release behavior of these devices, quantitative information on the microgeometry of the system is required. We present a computer-based system for obtaining estimates of the system porosity, isotropy, particle shape, and particle size distribution from observations on two-dimensional sections from the polymer matrix. 

In the area of controlled release, the preparation of indomethacin sustained-release microparticles from alginic acid (alginate)-gelatin hydrocolloid coacervate systems has been investigated. In addition, as controlled-release systems for liposome-associated macromolecules, microspheres have been produced encapsulating liposomes coated with alginic... 

In summary, the studies reported In this review provide 2 Important demonstrations (1) that In vitro release kinetics of macromolecules such as inulln from ethylene-vinyl acetate copolymer matrices are Identical to their In vivo release kinetics, and (2) that zero-order release for macromolecules can be achieved for over 60 days using a hemisphere design. Further experimentation in these areas should provide Information that will be useful In the eventual design of controlled release systems for Insulin and other important bloactlve macromolecules. 

Pea is a renewable reservoir for functional macromolecules. Pea proteins or starches can be used for packaging applications, such as films, foams and controlled release systems. The functionality of the biopolymers is influenced by technological treatments and altered by physical, enzymatic or chemical modifications. This work is aimed at obtaining detailed knowledge about the structure-property relationships of pea-based biodegradable plastics. 

POLYMER SYSTEMS FOR CONTROLLED RELEASE OF MACROMOLECULES, IMMOBILIZED ENZYME MEDICAL BIOREACTORS,... 

The area of applied bioactive polymeric systems includes such diverse entities as controlled release systems (erodable systems, diffusion controlled systems, mechanical systems and microcapsules), and biologically active polymers, such as natural polymers, synthetic polypeptides, pseudo-enzymes, pseudo-nucleic acids and polymeric drugs. The area can also include immobilized bioactive materials, such as immobilized enzymes, antibodies and other bioactive agents and the area of artificial cells. This Chapter reviews the general field of biologically active synthetic and modified natural macromolecules with an emphasis on their common characteristics, problems and applications. The areas reviewed include both medical and non-medical applications for both controlled release systems and polymers that exhibit direct biological activity. 

Bernkop-Schnurch, A., C.E. Kast, and D. Guggi. 2003. Permeation enhancing polymers in oral delivery of hydrophilic macromolecules Thiomer/GSH systems. J Control Release 93 95. 

Choksakulnimitr S, Masuda S, Tokuda H et al (1995) In vitro cytotoxicity of macromolecules in different cell culture systems. J Control Release 34(3) 233—241... 

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