Effect of Annealing on Drug Release and Nanocoating of Antibacterial Schanz Pin

Abstract

Nanocoating applications for antibacterial coating of medical devices have garnered interest in recent years. Many coating techniques have been developed; however, dip coating and spray coating are the simplest and easiest to transfer to upscaled production. Moreover, annealing treatment has been shown to alter the properties of the polymer film and alter the release profile. In this study, Vancomycin was entrapped on the threaded region of Schanz pin with a poly(3-caprolactone) film by layer-by- layer dip coating and spray coating. The results of the sample subjected to a 1-hour annealing treatment at 45°C were compared with those of the control sample that didn't undergo annealing. The study showed that the combination of spray coating of PCL nanosphere with dip coating and annealing treatment could reduce the burst release of vancomycin and prolong its release from coated Schanz pin for up to 28 days. Annealing caused a 10% reduction in the burst release phase of the release profile, while also prolonging a similar release of vancomycin for 1 week. Annealing also had an impact on the morphology of the coating. FESEM observations showed that annealing reduced the porosity of the coating, with deposited nanospheres partially melting together with the film. The results suggested that the annealing process contributed to a less porous and denser PCL film, thus decreasing the diffusion rate of vancomycin through the film. This method also provides another venue for tuning the properties of the polymeric nanocoating, which are not affected by the common limitation of the upscaling process.