The sweat test is the gold standard for the diagnosis of cystic fibrosis (CF). The test utilizes iontophoresis to administer pilocarpine to the skin to induce sweating for measurement of chloride concentration in sweat. However, the sweat test procedure needs to be conducted in an accredited lab with dedicated instrumentation, and it can lead to inadequate sweat samples being collected in newborn babies and young children due to variable sweat production with pilocarpine iontophoresis. We tested the feasibility of using microneedle (MN) patches as an alternative to iontophoresis to administer pilocarpine to induce sweating. Pilocarpine-loaded MN patches were developed. Both MN patches and iontophoresis were applied on horses to induce sweating. The sweat was collected to compare the sweat volume and chloride concentration. The patches contained an array of 100 MNs measuring 600 μm long that were made of water-soluble materials encapsulating pilocarpine nitrate. When manually pressed to the skin, the MN patches delivered >0.5 mg/cm² pilocarpine, which was double that administered by iontophoresis. When administered to horses, MN patches generated the same volume of sweat when normalized to drug dose and more sweat when normalized to skin area compared to iontophoresis using a commercial device. Moreover, both MN patches and iontophoresis generated sweat with comparable chloride concentration. These results suggest that administration of pilocarpine by MN patches may provide a simpler and more-accessible alternative to iontophoresis for performing a sweat test for the diagnosis of CF.

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通过微针贴片施用毛果芸香碱作为囊性纤维化汗液测试的新方法

汗液试验是诊断囊性纤维化 (CF) 的金标准。该测试利用离子电渗疗法向皮肤施用毛果芸香碱以诱导出汗，以测量汗液中的氯化物浓度。但是，汗液测试程序需要在配备专用仪器的认可实验室中进行，并且由于毛果芸香碱离子电渗疗法产生的汗液产生量不同，因此可能会导致在新生儿和幼儿中收集的汗液样本不足。我们测试了使用微针 (MN) 贴片替代离子电渗疗法来施用毛果芸香碱诱导出汗的可行性。开发了装载毛果芸香碱的 MN 贴剂。MN 贴片和离子电渗疗法都应用于马以诱导出汗。收集汗液以比较汗液量和氯化物浓度。这些贴片包含一排 100 MN，长 600 μm，由封装了硝酸毛果芸香碱的水溶性材料制成。当手动按压皮肤时，MN 贴片输送 >0.5 mg/cm²毛果芸香碱，是离子电渗疗法的两倍。与使用商业设备的离子电渗疗法相比，当对马施用时，MN 贴片在标准化为药物剂量时产生相同体积的汗水，而在标准化为皮肤面积时产生更多的汗水。此外，MN 贴片和离子电渗疗法都产生了具有可比氯化物浓度的汗液。这些结果表明，通过 MN 贴片施用毛果芸香碱可以提供一种更简单、更容易获得的替代离子电渗疗法的方法，用于进行汗液测试以诊断 CF。