Method for assessing coating uniformity of angioplasty balloons coated with poly(lactic-co-glycolic acid) nanoparticles loaded with quercetin

Abstract

In this study, we aim to quantify coating uniformity and correlate fluorescence intensity to drug loading for drug-coated angioplasty balloons (DCB) coated with 5, 10, 15, or 20 layers of poly(lactic-co-glycolic acid) nanoparticles (NPs) entrapped with quercetin. Uniformity was quantified from histograms and horizontal line profiles of microscopic fluorescent images acquired with sample specific parameters, and cracks in the coating were measured and counted. The fluorescence of images acquired with global parameters was correlated with quercetin loading measured via gravimetric/HPLC analysis. More layers on DCBs may be associated with less uniform coatings, as indicated by differences in histogram standard deviations. The line profile percent deviation from average for each sample was <20%. Cracks were present on all balloons, but their length was not significantly different between samples. The 5-layer DCBs had the fewest cracks, whereas the 15-layer DCBs had the most cracks. A strong positive correlation (R = 0.896) was identified between fluorescence intensity and drug loading. A relationship between the number of layers and coating uniformity seems to exist, but further investigations are required for confirmation. Fluorescence intensity appears to strongly predict drug loading, demonstrating that fluorescent imaging may be a viable alternative to drug release studies.