Kelchen Megan N, Siefers Kyle J, Converse Courtney C, Farley Matthew J, Holdren Grant O, Brogden Nicole K
University of Iowa College of Pharmacy, Department of Pharmaceutical Sciences and Experimental Therapeutics, 115 S. Grand Ave, Iowa City, IA 52242, USA.
University of Iowa College of Pharmacy, Department of Pharmaceutical Sciences and Experimental Therapeutics, 115 S. Grand Ave, Iowa City, IA 52242, USA; University of Iowa Carver College of Medicine, Department of Dermatology, 200 Hawkins Dr, Iowa City, IA 52242, USA.
J Control Release. 2016 Mar 10;225:294-300. doi: 10.1016/j.jconrel.2016.01.051. Epub 2016 Jan 30.
Transdermal delivery is an advantageous method of drug administration, particularly for an elderly population. Microneedles (MNs) allow transdermal delivery of otherwise skin-impermeable drugs by creating transient micropores that bypass the barrier function of the skin. The response of aging skin to MNs has not been explored, and we report for the first time that micropore closure is delayed in elderly subjects in a manner that is dependent upon MN length, number, and occlusion of the micropores. Twelve control subjects (25.6±2.8years) and 16 elderly subjects (77.3±6.8years) completed the study. Subjects were treated with MNs of 500μm or 750μm length, in arrays containing 10 or 50 MNs. Impedance measurements made at baseline, post-MN insertion, and at predetermined time points demonstrated that restoration of the skin barrier is significantly slower in elderly subjects under both occluded and non-occluded conditions. This was confirmed via calculation of the total permeable area created by the micropores (which would approximate the area available for drug delivery), as well as calculation of the micropore half-life. This pilot study demonstrates that longer timeframes are required to restore the barrier function of aged skin following MN insertion, suggesting that drug delivery windows could be longer following one treatment with a MN array.
经皮给药是一种有利的给药方法，尤其适用于老年人群。微针（MNs）通过制造瞬时微孔绕过皮肤的屏障功能，从而实现原本无法透过皮肤的药物的经皮给药。衰老皮肤对微针的反应尚未得到研究，而我们首次报告，老年受试者中微孔闭合延迟，且这种延迟取决于微针的长度、数量以及微孔的封闭情况。12名对照受试者（25.6±2.8岁）和16名老年受试者（77.3±6.8岁）完成了该研究。受试者接受了长度为500μm或750μm的微针治疗，微针阵列包含10根或50根微针。在基线、微针插入后以及预定时间点进行的阻抗测量表明，在封闭和非封闭条件下，老年受试者皮肤屏障的恢复均明显较慢。这通过计算微孔形成的总渗透面积（近似于可用于药物递送的面积）以及微孔半衰期得到了证实。这项初步研究表明，微针插入后，恢复老年皮肤屏障功能需要更长的时间，这表明使用微针阵列进行一次治疗后，药物递送窗口可能会更长。
