Implants that dissolve in the body within a defined period of time represent a particular challenge. For a long time now, implants such as these have been developed and used to fix small bone fragments in place, for instance. The self-dissolving polymers used for this include: polylactide (PLA), polyglycolid (PGA), polydioxanon (PDS), poly hydroxy butyric acid (PHB) and polyorthoester (POE). Pins made of PDS (Ethipin) and PGA (Biofix), for instance, have been used clinically since 1985. However, both materials degrade very quickly and therefore rapidly lose their strength. The degradation times were increased significantly by using the polymer PLA.

Cardiovascular implants - a market worth billions


The market for cardiovascular implants, worth around $ 15 billion worldwide, is considered extremely attractive. In addition, the importance of coating technologies for catheters and stents is increasing because, amongst other reasons, they make innovative and individualized medical therapies possible. "Coatings increase functionality, lifetime and cost efficiency, improve the guidance and positioning of parts, and they facilitate handling and reduce the patient's risk of injury," explains Prof. Hans-Wilhelm Engels, Head of the Innovation Community Council and Head of Research in the area of paints, adhesives and specialties at Bayer MaterialScience (COMPAMED exhibitor). The coating materials that can be used include hydrophile polymers and polymers with good gliding properties such as polyvinyl pyrrolidone (PVP), polyethylene glycol / poly ethylene oxide (PEG/PEO), polyvinyl alcohol (PVA) as well as hyaluronic acid. As these compounds are often water soluble they must be stabilized through cross-linking. Just recently Bayer introduced Baymedix CD 500, a new coating into which the agents can be integrated. These stable coatings allow the programmable release of a number of different agents, from small molecules all the way to protein therapeutics. The biocompatibility of these systems was confirmed in in-vitro and in-vivo tests. "We are also already working on optimal systems for biodegradable stents," says Prof. Engels.

Maximum stability through "bone welding"

A procedure in bone surgery has been creating a furor for several years now as the idea originated in the watch manufacturing industry and was developed further in the furniture industry. The procedure in question is the WoodWelding technology of the Swiss company WoodWelding. In this procedure, also known as bone welding, synthetic implants (lactic acid polymers) are fixed in the bone by means of ultrasound.

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