Coating of collars via fluidised-bed process

Abstract

Collars are small cylindrical tubes which serve as drug reservoirs that are fitted directly on the lead tip of a pacemaker electrode to reduce inflammatory response after the implantation. Currently, collars are produced by injection moulding which may be associated with content variability and long manufacturing times. Hence, the goal of this study was to adapt the effective fluidised-bed process for coating of collars. In this study, collars were coated in a fluidised-bed apparatus with Eudragit ®RS 30D as an aqueous dispersion which contained the water-soluble model substance fluorescein-sodium. The process parameters and the composition of coating liquid were adapted to obtain a smooth coating surface. Throughout this investigation the surface morphology of the coated collars was explored by using different microscopic methods. Additionally, the homogeneity of coating content was determined fluorometrically and by differential weighing. Our findings provide a basis for coating of collars via fluidised-bed technology. The fluidised-bed technology was applicable to produce collars with a microscopic smooth surface and high homogeneity of drug content. Nevertheless, further optimizations of the coating composition are necessary to create a coating which is flexible and robust enough to mount the collar onto the pacemaker lead without causing coating defects. © 2012 by Walter de Gruyter. Berlin. Boston.