Characterization of Time-Dependent Dissolution of Hydrophilic PTCA Catheter Coating Particles Using Dynamic Image Analysis

Abstract

Hydrophilic polymer coatings are widely used in percutaneous transluminal coronary angioplasty (PTCA) catheter systems to improve lubricity and trackability. However, the release of coating-derived particles during device use represents a relevant aspect of device safety evaluation. While established standards such as USP<788> define methods for particulate analysis in pharmaceutical products, the application of advanced imaging techniques such as dynamic image analysis (DIA) is not yet fully addressed in catheter-specific standards (e.g., ISO 10555-1:2023). In this study, a simulated use model based on ASTM F2394-07(2022) was employed to generate particle solutions during simulated use test of two PTCA catheter systems. Particle suspensions were analyzed using DIA at three defined time points after collection (t₁ = 0 h, t₂ = 4 h, t₃ = 24 h). Particle size distributions were evaluated in size classes between 10 μm and 500 μm. For both devices, particle counts decreased significantly over time, with reductions of more than 50 % after 24 h in the clinically relevant size range of 10-100 μm. A substantial fraction of this decreases (30- 45 %) already occurred within the first 4 h, indicating a pronounced early-phase dissolution of hydrophilic coating particles. These findings demonstrate that hydrophilic particles exhibit time-dependent dissolution in aqueous environments, reducing their persistence over time. However, as particle-related risks are primarily associated with the acute phase following release, immediate particle characterization is essential. The results highlight the importance of standardized timing in particle analysis to ensure reliable and comparable assessment of hydrophilic coating-derived particles.