Three-dimensional compositional analysis of drug eluting stent coatings using cluster secondary ion mass spectrometry.
Three-dimensional compositional analysis of drug eluting stent coatings using cluster secondary ion mass spectrometry.
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DOI：
10.1021/ac701644j
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发表时间：
2008-01
影响因子：
7.4
通讯作者：
C. Mahoney;A. Fahey;A. Belu
中科院分区：
文献类型：
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作者：
C. Mahoney;A. Fahey;A. Belu
采用SF5+多原子一次离子溅射源与Bi3+分析源结合的簇次离子质谱法（Cluster secondary ion mass spectrometry， SIMS）用于获得聚合物基药物洗脱支架涂层中的三维分子信息。涂层的配方从0%到50% （w/w）的西罗莫司药物在聚（乳酸-羟基乙酸）中，制备在MP35N金属合金片和裸金属支架上。所有获得的团簇SIMS深度剖面都显示了一个药物富集的表面区域，然后是一个药物耗尽区域，最后是一个恒定的体组成区域，类似于先前在聚合物共混体系中获得的数据。药物覆盖层厚度随西罗莫司含量的增加而增加。样品温度被确定在得到的深度剖面中起重要作用，其中表明在低温（-100℃）下获得最佳剖面。在这些温度下，分子信号通常在膜的整个深度（约6.5微米）保持恒定，而不是在室温下可以达到的典型的1微米-2微米深度限制。簇SIMS的三维成像能力被成功证明，并表明在25%和50%的西罗莫司样品中有大量的地下区域形成，但在5%的样品中没有，这是均匀的。这些结果清楚地说明了簇SIMS在探测基于聚合物的药物输送装置的三维结构方面的实用性。
Cluster secondary ion mass spectrometry (cluster SIMS) employing an SF5+ polyatomic primary ion sputter source in conjunction with a Bi3+ analysis source was used to obtain three-dimensional molecular information in polymeric-based drug-eluting stent coatings. The formulations of the coatings varied from 0% to 50% (w/w) sirolimus drug in poly(lactic-co-glycolic acid) and were prepared on both MP35N metal alloy coupons and bare metal stents. All cluster SIMS depth profiles obtained indicated a drug-enriched surface region, followed by a drug-depletion region, and finally a constant bulk composition region, similar to previous data obtained in polymeric blend systems. The drug overlayer thickness was determined to increase with increasing sirolimus content. Sample temperature was determined to play an important role in the resulting depth profiles, where it was shown that the best profiles were obtained at low temperatures (-100 degrees C). At these temperatures, molecular signals typically remained constant through the entire depth of the film (approximately 6.5 microm) in some cases, as opposed to the typical 1 microm-2 microm depth limit, which is achievable at room temperature. The 3-D imaging capabilities of cluster SIMS were successfully demonstrated and indicated a significant amount of subsurface domain formation in the 25% and 50% sirolimus samples, but not in the 5% sample, which was homogeneous. These results clearly illustrate the utility of cluster SIMS for probing the 3-D structure in polymeric-based drug delivery devices.