Development and in vitro characterization of hyaluronic acid-based coatings for implant-associated local drug delivery systems

The development of drug-eluting coatings based on hyaluronic acid (ha) is especially promising for implant-associated local drug delivery (ldd) systems,whose implantation provokes high insertion forces,as,for instance,cochlear implants or drug-coated balloons (dcb). the lubricious character of ha can then reduce the coefficient of friction and serve as drug reservoir simultaneously. in this context,we investigated several plasma- and wet-chemical methods for the deposition of ha-based coatings with ldd function on polyamide 12 as a model implant surface,conventionally used for dcb. in contrast to aminosilane,epoxy silane surface layers allowed the covalent attachment of a smooth and uniform ha base layer,which provided good adherence of further ha layers deposited by manual dip coating at a subsequent processing stage. the applied ha-crosslinking procedure during dip coating influences the transfer and release of paclitaxel,which could be reproducibly incorporated via infiltration. while crosslinking with n-(3-dimethylaminopropyl)-n′-ethylcarbodiimide hydrochloride provided ha coatings on dcb,which allowed for an efficient paclitaxel transfer upon expansion in a vessel model,crosslinking with glutardialdehyde resulted in a slower drug release being more appropriate for implants with longer residence time in the body. the developed ha coating is hence well suited for spontaneous and sustained ldd. © 2013 svea petersen et al.