Polymer membrane permeation-controlled

Polymer membrane permeation-controlled drug delivery systems. 

Polymer Membrane Permeation-Controlled Drug Delivery Systems... 

Fig. 3 Release of drug from various shapes of pol5mer membrane permeation-controlled drug-delivery systems (A) sphere-type, (B) cylinder-type, and (C) sheet-type. In (D), the drug concentration gradients across the rate-controlling polymeric membrane and hydrodynamic diffusion layer exist in series. Both the polymer membrane, which is either porous or non-porous, and the diffusion layer have a controlled thickness and h, respectively).

Chemical modifications of PPO by electrophilic substitution of the aromatic backbone provided a variety of new structures with improved gas permeation characteristics. It was found that the substitution degree, main chain rigidity, the bulkiness and flexibility of the side chains and the polarity of the side chains are major parameters controlling the gas permeation properties of the polymer membrane. The broad range of solvents available for the modified structures enhances the possibility of facile preparation of PPO based membrane systems for use in gas separations. 

K Ishihara, M Kobayashi, N Ishimaru, I Shinohara. Glucose induced permeation control of insulin through a complex membrane consisting of immobilized glucose oxidase and a poly(amine). Polym J 8 625-631, 1984. 

TEMPERATURE-CONTROLLED SOLUTE PERMEATION Preparation of Polymer Membrane... 

The insoluble cellulose derivatives utilized for permeation control of various species (e.g. oxygen and water vapor transport in coated pharmaceuticals, contact lenses, packaging, or water and solute transport through semi-permeable membranes in reverse osmosis, as well as drug release from reservoir systems) differ considerably in their permeability characteristics according to the type and extent of substitution, as well as their molar mass. However, very few comparative data are available from the literature on the polymers actually used in biological applications. Recently, new results have been published. Thus, Sprockel et al. [142] determined the water vapor transmission through various CA, CAT, CAB and CAPr films at different relative humidities (Table 22). 

K. Ishihara, N. Hamada, S. Kato and I. Shinohara, Photoresponse of the release behavior of an organic compound by a azoaromatic polymer device, J. Polym. Sci., Polym. Chem. Ed., 1984, 22, 881 K. Ishihara and I. Shinohara, Photoinduced permeation control of protein using amphiphilic azoaromatic polymer membrane, J. Polym. Sci., Polym. Lett. Ed., 1984, 22, 515-518 J. Matejka, M. Ilavsky, K. Dusek and O. Wichterle, Photochemical effects in cross-linked photochromic polymer, Polymer, 1981, 22, 1511. 

Ishihara K, Kobayashi M, Shinohara I. Control of insulin permeation through a polymer membrane with responsive function for glucose. Makromol Chem Rapid Commun 1983 ... 

Rubbery polymers provide solubility-controlled permeation. In this case, e.g. hydrocarbon gases can be separated according to their molecular mass and solubility in membrane film heavier gases have a better solubility, so they permeate faster under the action of larger driving force. 

Permeation control through stimuli-responsive polymer membrane prepared by plasma and radiation grafting techniques... 

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