Polymeric implants non-degradable

Non-degradable polymeric implants are divided into two main types (see also section 3.2) [Pg.77]

In both cases, drug release is governed by diffusion, i.e. the drug moiety must diffuse through the polymer membrane (for a reservoir device) or the polymeric matrix (for a matrix device), in order to be released. [Pg.78]

The choice of whether to select a reservoir-type, or a matrix-type, implantable system depends on a number of factors, including [Pg.78]

For example, it is generally easier to fabricate a matrix-type implant than a reservoir system, so this may determine the selection of a matrix system. However, if drag release is the overriding concern, a reservoir system may be chosen in preference to a matrix system. This is because reservoir systems can provide zero-order controlled release, whereas drag release generally decreases with time if a matrix system is used. [Pg.78]

Poly(ethylene-co-vinyl acetate) (EVA copolymer) is also widely used as a non-degradable polymeric implant. These copolymers have the advantages of [Pg.78]

Reservoir/matrix hybrid-type non-degradable polymeric implants are also available. Such systems are designed in an attempt to improve the M t1/2" release kinetics of a matrix system, so that release approximates the zero-order release rate of a reservoir device. Examples of these types of systems include ... [Pg.87]

The release rate of a dmg from conventional non-degradable matrix-type polymeric implant usually decreases over time. Describe a technique that can be used to overcome this problem. [Pg.103]

Which polymer is most extensively used as non-degradable nonporous membrane to develop reservoir-type polymeric implants ... [Pg.103]

Keywords Eye diseases, ocular drug delivery, polymeric drug dehvery systems, implants, bio degradable/non-bio degradable p olymers... [Pg.439]

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