Bioresorbable polymers implants

Kostopoulos, L., Karting, T. 1994. Guided bone regeneration in mandibular defects in rats using a bioresorbable polymer. Clinical Oral Implants Research 5 666-674. 

This phenomenon is related to another interesting feature of bioresorbable polymers. Degradation products are removed by the cells themselves in order to achieve a complete degradation of the implanted device. As an example. 

Bioresorbable polymers are put to extensive use as medical materials because of their diverse biodegradability, good mechanical properties and biocompatibility. The ability to tailor their chemical structures to control their degradation behaviour and rate is a great advantage when it comes to designing implants with suitable mechanical and degradational properties for their intended use. 

The lactide/glycolide bioresorbable polymers are thermoplastics which can be processed by many methods, including fibre spinning, extrusion, and injection moulding, which means they can be fabricated into a variety of wound closure items (e.g. sutures), implantable devices (e.g. bone plates, bone screws), and drug delivery systems, which include microspheres, fibres, films, rods and others. 

When designing a medical device based on a bioresorbable polymer, the degradation ability of the material during all the phases from the synthesis to the complete resorption in vivo must be carefully considered. In this regard, synthetic polymers are more versatile compared to natural origin polymers, thereby allowing a finer control of the theoretical degradation rate. However, this rate depends from a number of external factors such as production process conditions (eg, humidity, temperature) and site of implantation (eg, pH, mechanical stress) [13—18]. 

Every year, more than 2 million bone-grafting procedures are performed worldwide for orthopedic treatments, such as firactures, tumor resections, and osteoporosis. Theoretically, orthopedic devices based on bioresorbable polymers can overcome the drawbacks associated to biostable implants, such as corrosion and ion accumulation (metals and alloys), formation of nondegradable debris creating pain and... 

In this chapter, we provide a brief overview on the anatomy of the eye. The majority of bioresorbable polymers that are used clinically are in ocular drug delivery, and we highlight some of the bioresorbable polymers that are being used. In subsequent sections, we focus on the research and development of various implants, particularly those for inducing regeneration in various parts of the eye, that involve the use of bioresorbable polymers. 

Corneal implants prepared solely from natural bioresorbable polymers... 

In summary, both synthetic and naturally occurring bioresorbable polymers are both very promising materials for ophthalmic application. These materials offer different advantages and are therefore used for different applications varying from drug delivery vehicles to solid implants and in-site geUing injectables. 

PLA is a biodegradable, bioresorbable polymer fiiat can be assimilated by the body and has important applications in sustained-release drug delivery systems. The mechanical properties and absorbability of PLA make it an ideal candidate for implants in bone and soft tissue and for resorbable sutures. 

Bioresorbables Polymers that can be fully eliminated from the body. These polymer implants undergo bulk degradation and are resorbed in vivo and then naturally metabolized. Such bioresorbable polymers do not cause side effects... 

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