Polymeric devices

The classification of polymers for oral drug delivery can be done by using various means. To make this discipline readily accessible to the novice reader, the hydro-phobic-hydrophilic nature of the polymer was chosen to group polymers since the mechanism of biomacromolecule release from most hydrophobic polymeric devices is similar the mechanism of release from most hydrophilic polymeric devices also have similar mechanisms. Hydrophobic polymers are described first, followed by hydrophilic polymers. 

Kimura H.-O.Y., Hashizoe, M., Nishiwaki, H., Honda, Y. and Ikada, Y. (1994) A new vitreal drug delivery system using an implantable biodegradable polymeric device. Investigative Ophthalmology and Visual Science, 35 2815-2819. 

Peppas and coworkers [64,68] introduced a semiempirical equation (the so-called power law) to describe drug release from polymeric devices in a generalized way ... 

Sponges Progesterone, estradiol, and several progestins Polyurethane Polymeric devices impregnated with active substance(s), usually cylindrical shaped alternative designs allow achieving zero-order release profile Variable vaginal retention inexpensive and simple to prepare... 

Despite such impressive progress, considerable challenges still lie ahead, and the more signihcant challenge is to improve the stability of G-quartet dynamic aggregates in polymeric devices such as hlms or membranes to extend (address) the transport studies at macroscopic level. Several studies reported the preparation of discrete supramolecular assemblies of nucle-obases. However, the dynamic communication between the... 

In this review dealing with recent advances in membrane science, the term membrane" will be used to indicate any medium which acts as a barrier to transport into or out of a region, provides selective transfer of one species over another or regelates the transport of a material to its environment at a controlled rate. In addition to the common usage of the word membrane" to indicate a dense polymer film, the above definition includes a variety of interesting cases such as highly porous ultrafiltration membranes and hydrophobic liquid membranes with selectivity properties which can be tailored by incorporation of materials which selectively complex with one of the species to be processed. The important topics of controlled release of chemicals from polymeric devices and removal of volatile monomers from addition polymers such as poly (vinyl chloride and poly (acrylonitrile are also treated here. 

Narasimhan B and Danger R. Zero-order release of micro- and macromolecules from polymeric devices The role of the burst effect. J. Control. Rel. 1997 47 13-20. 

Vert M, Li S, Garreau H. New insights on the degradation of bioresorbable polymeric devices based on lactic and glycolic acids. Clin Mater 1992 10 3-8. 

Moreover, because of the presence in the tank of many types of materials (including natural organic particulates, polymeric devices, semi-permeable membranes and solid sorbents used for other types of measurements), a partial adsorption of PAHs leading to concentration depletion, at least at the beginning of the exercise, of the dissolved (free) PAHs is also highly plausible. This may also contribute to some extent to the low concentrations found for the four PAHs (ANTH, BaA, CHRY, and PYR) from samplings T4 to T9. 

Tatard VM, Menei P, Benoit JP, et al. Combining polymeric devices and stem cells for the treatment of neurological disorders a promising therapeutic approach. Curr Drag Targets 2005 6 81-96. 

Hashizoe M, Ogura Y, Takanashi T, Kunou N, Honda Y, Ikada Y. Implantable biodegradable polymeric device in the treatment of experimental proliferative vitreoretinopathy. Curr Eye Res 1995 14 473-477. 

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