A molecular imaging application was developed to characterize the drug distribution on CYPHER® and NEVO™ Drug-eluting Stents using MALDI Qq-ToF analytical methodology. The coating matrix, laser energy, laser frequency, spatial resolution (related to rastering speed) and mass spectrometer parameters were optimized to analyze drug distribution in both durable and biodegradable polymer matrices. The developed method was extended to generate data from stents explanted from porcine coronary arteries. Due to the method's intrinsic specificity, it offers a significant advantage over other techniques in that it allows low-level detection of the target molecule without biological interferences from the blood or tissue. The method is also capable of detecting drug-related degradation products both from the finished stent product and from explanted stents.

Measuring the residual polyethylene glycol (PEG) in polyethylene oxide (PEO)-based surfactants is important to fully understanding the performance of these materials. Traditional methods of quantitating PEG in PEO-based surfactants can be time-consuming and struggle with low amounts or overlapping molecular mass distributions. This paper describes a matrixassisted laser desorption/ionization (MALDI) mass spectrometry method developed to quantitate residual PEG in a series of ethoxylated surfactants. The technique addresses the difficulties faced in doing quantitative MALDI experiments by utilizing both internal standard and standard additions protocols. The method produces excellent straight line standard addition plots, and the quantitative results are verified using both a constructed standard and an independent traditional chromatographic separation.

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