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Original title:
Eine resorbierbare Poly-D,L-Laktid-Beschichtung zur Ausrüstung medizinischer Implantate:
Original subtitle:
mit antithrombogenen Oberflächen in der Neonatologie und antiinfektiven Oberflächen in der Orthopädie
Translated title:
A biodegradable poly-D,L-lactic acid coating for medical implants
Translated subtitle:
Antithrombogenic surfaces for neonatology and antiseptic surfaces for orthopaedic surgery
Gollwitzer, Hans
Document type:
Fakultät für Medizin
Stemberger, A. (Prof. Dr. rer. nat. Dr. med. habil.)
Stemberger, A. (Prof. Dr. rer. nat. Dr. med. habil.); Pontz, B. (Prof. Dr. Dr.); Neumeier, Dieter (Prof. Dr.)
Subject group:
MED Medizin
Polymilchsäure; Arzneistoffträger; Oberfläche; antiinfektiös; antithrombogen
Translated keywords:
polylactide; drug delivery; surface; anti.infective; anti-thrombogenic
Implantat-assoziierte Infektionen und Thromboembolien sind beim Einsatz von Biomaterialien gefürchtete Komplikationen. Um das Auftreten dieser Komplikationen zu reduzieren werden neue Strategien zur Optimierung der Implantatoberfläche entwickelt. Ziel der vorliegenden Arbeit war es, eine neue bioresorbierbare Oberflächenbeschichtung auf der Basis von Poly-D,L-Laktid hinsichtlich der mechanischen Eigenschaften zu prüfen. Weiter war es Aufgabe, eine neue Antibiotika-Polylaktid-Kombination als anti...    »
Translated abstract:
Biomaterial-associated infections and thromboembolic complications represent common and challenging side reactions following the application of medical implants. New strategies to optimize implants concern the development of surface coatings. The main purpose of the present study was to evaluate the mechanical properties of a new biodegradable, low molecular weight poly-D,L- lactic acid (PDLLA) surface coating, further on, the antiseptic properties of the PDLLA coating with incorporated antibiotics. The second part of these investigations revealed an antithrombogenic coating for central venous lines. The polymer coating was applied by a solvent casting technique in volatile organic solvents. The influence of the organic solvent, the polymer and the polymer concentration on the mechanical stability of the coating was studied in clinically oriented models. After intramedullary implantation in human cadaveric femora, PDLLA coating demonstrated less than 4% of weight loss. Abrasion of the coating occured uniformly at the inner cortex. Thickness and stability of the coating could be modified by changing organic solvent and/or polymer concentration. PDLLA coating tolerated lenthening of the implant of at least 8%. A blend of PDLLA with polymers suh as poly-L-lactide-co-trimethylene-carbonate increased flexibility of the surface coating. To create an antiseptic surface coating antibiotics such as gentamicin and teicoplanin were integrated in the biodegradable polymer with a concentration of 5%. In vitro drug release was characterized by an initial peak throughout the first hours and a continuous release for at least 96 hours. Teicoplanin release was clearly delayed as compared with gentamicin, and after 6 hours the remaining antibiotics were released continuously showing similar kinetics. Bactericidal activities of the polymer-anitbiotic-combination were studied in the presence of high concentrations of pathogenic bacteria in vitro. Adhesion of viable bacteria was reduced significantly by the pure polymer (P<0.05) and further by the polymer-antibiotic combinations (P<0.05). Further on, the developed antithrombogenic PDLLA coating was modified for the application with central venous lines. Even catheters used in neonatology could be coated uniformly with the modified solvent casting technology. The antithrombogenic properties of the coating could be confirmed in a modified "human stasis" model. Poly-D,L-lacitic acid can be applied as a stable, biodegradable and biocompatible polymer to create antithrombogenic and antiseptic surface coatings of medical implants. The polymer can be combined with a broad variaty of drugs to create custom-tailored implant surfaces offering new opportunities to improve the use of established biomaterials.
Publication :
Universitätsbibliothek der TU München
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