Drug Release Profiles of Different Drug-coated Balloon Platforms

Abstract

Drug-coated balloons are a new tool for the treatment of de novo or in-stent stenosis; as yet little is known about the principle by which these devices apply their therapeutic agents during intervention. Concerns remain regarding clinical safety and efficacy of different coatings, mainly influenced by the amount of drug transferred into the arterial tissue and lost into the bloodstream. To assess whether the chemical or mechanical set-up influences drug migration and wash-off, we compared four paclitaxel-coated balloon platforms differing in surface structure (folded versus non-folded) and coating compounds (pure paclitaxel versus paclitaxel plus excipient) in a porcine coronary model. The study revealed high wash-off rates for all devices, exceeding 54.4% of the initial coating contents. In terms of tissue concentration significant differences could be observed between the coating compounds independently from the device platform. For the paclitaxel versus paclitaxel plus excipient balloons tissue concentrations of 0.02 and 0.33μg/mm2, respectively (p<0.01), were detected; for the paclitaxel versus paclitaxel plus excipient-wrapped balloons tissue concentrations were 0.13 and 0.53μg/mm2, respectively (p=0.04). The main driver of drug migration from drug-coated balloon surfaces into arterial tissue is the chemical set-up of the coating. Hydrophilic excipients allow higher tissue concentrations of paclitaxel independent from the mechanical platform. The wash-off from the surface coating remains an unsolved safety issue and may be solved by mechanical modifications of these devices.