Functionalizing implant surfaces is critical for improving their performance. An integrated approach was employed to develop a multifunctional implant coating based on oxygen plasma-modified parylene C and drug-loaded, biodegradable poly(dl-lactide-co-glycolide) (PLGA). The key functional attributes of the coating (i.e., anti-corrosion, biocompatible, anti-infection, and therapeutic) were thoroughly characterized at each fabrication step by spectroscopic, microscopic, and biologic methods and at different scales, ranging from molecular, through the nano- and microscales to the macroscopic scale. The chemistry of each layer was demonstrated separately, and their mutual affinity was shown to be indispensable for the development of versatile coatings for implant applications.

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Shape-memory polymers (SMPs) that combine shape-memory, biodegradability, and controlled drug release properties are very promising for medical and pharmaceutical application. Moreover, incorporation of antirestenotic drug into SMP biodegradable stent seems to be an interesting solution because of possibility to combine the mechanical support that provides stent and also drug elution. The aim of our study was to analyze the effect of incorporation of sirolimus into poly(L-lactide-co-glycolide-co-trimethylene carbonate) on physicochemical and mechanical properties, degradation, and shape-memory effect of the terpolymer. For this purpose, sirolimus was incorporated into the terpolymer by injection molding method. It has been demonstrated that drug-free terpolymer after injection molding characterized insignificant changes in terpolymer composition. Degradation of materials during processing was not observed. Incorporation of drug molecules did not change shape-memory properties of terpolymer.1 H-and 13 C-NMR spectra of poly(lactide-co-glycolide-co-trimethylene carbonate) confirmed that changes during degradation were similar for terpolymer and terpolymer with sirolimus. Sustained and regular release of sirolimus was observed. The developed material presents potential for biomedical and pharmaceutical applications.

A series of copolymers have been synthesized by the ring-opening polymerization of glycolide, L-lactide, and e-caprolactone with zirconium(IV) acetylacetonate [Zr(Acac) 4 ] or stannous octoate [Sn(Oct) 2 ] as the catalyst. The resulting terpolymers have been characterized by analytical techniques such as proton nuclear magnetic resonance, size exclusion chromatography, and differential scanning calorimetry. Data have confirmed that Sn(Oct) 2 leads to less transesterification of polymer chains than Zr(Acac) 4 under similar conditions. The various copolymers have been compressionmolded and allowed to degrade in a pH 7.4 phosphate buffer at 378C. The results show that the degradation rate depends not only on the copolymer composition but also on the chain microstructure, the Sn(Oct) 2 -initiated copolymers degrading less rapidly than Zr(Acac) 4 -initiated ones with more random chain structures. The caproyl component appears the most resistant to degradation as its content increases in almost all cases. Moreover, caproyl units exhibit a protecting effect on neighboring lactyl or glycolyl units. The glycolyl content exhibits different features: it decreases because of faster degradation of glycolyl units, which are more hydrophilic than caproyl and lactyl ones, remains stable in the case of abundant CÀ ÀGÀ ÀC sequences, which are very resistant to degradation, or even increases because of the formation of polyglycolide crystallites. Terpolymers can crystallize during degradation if the block length of one of the components is sufficiently long, even though they are amorphous initially.

PurposeEstradiol (E2)-loaded poly(L-lactide-co-glycolide-trimethylenecarbonate) (P(L-LA:GA:TMC)) rods with shape-memory were developed for the treatment of neurodegenerative diseases. Usefulness of the extrusion method in the obtaining process was also considered. The influence of structural and surface properties during hydrolytic degradation was developed. The possible therapeutic aspect of rods with E2 was determined.MethodsThe extruded rods were incubated in a PBS solution (pH 7.4, 37°C, 240 rpm). The amount of released E2 in vitro conditions was estimated by UV-VIS method. The following methods in the degradation of rods were applied: NMR, DSC, FTIR, GPC, SEM, and optical microscopy. Changes in water uptake and weight loss were also determined. In vivo study was performed on rats. Measurements of E2 level were performed before and after ovariectomy of rats using ELISA method. A sample of tissue adjacent to the site of the rod implantation was analysed under an optical microscope.ResultsA stable and steady degradation process ensured zero-order release of E2. The in vivo study indicated a significant increase in the E2 level in serum after ovariectomy. Moreover, structural and surface features indicated that the extrusion method was appropriate for obtaining E2-loaded rods.ConclusionsShape-memory P(L-LA:GA:TMC) rods with E2 are an adequate proposal for further research in the field of neurological disorders.

The aim of this study was to determine the influence of long-term exposure of Ringer’s solution on degradation of the anodically oxidated Ti6Al4V alloy coated with a biodegradable polymer coating. Polymeric coatings made of poly(glycolide-ε-caprolactone) – G-Cap and poly(glycolide- ε-caprolactone-lactide) – G-Cap-L were applied by a dip-coating method. Degradation was assessed on the basis of the results of pitting corrosion resistance and density of metal ions infiltrating to the solution. Studies were conducted for samples after 3, 6, 8, 10 and 12 weeks of exposure to the corrosive environment. In addition, topography of the surface of the polymer coating was assessed. As a result of potentiodynamic studies, the value of the polarization resistance and corrosion potential for the G-Cap and G-Cap-L coated samples were significantly decreased while simultaneous reduction of the density of metal ions infiltrating to the solution throughout the whole study period. There was also observed a faster degradation of the G-Cap coating compared to G-Cap-L, which showed local discontinuity after 12 weeks of exposure. The obtained results provide the basis for the development of polymeric coatings on surface of metal implants with predictable time / kinetics of degradation by selecting the composition of polymers while simultaneous limitation of metal ions infiltration into surrounding tissues.

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