Kasting Gerald B, Bhatt Varsha D, Speaker Tycho J
James L Winkle College of Pharmacy, University of Cincinnati Academic Health Center, PO Box 670004, Cincinnati, OH 45267-0004, USA.
Toxicol In Vitro. 2008 Mar;22(2):548-52. doi: 10.1016/j.tiv.2007.11.003. Epub 2007 Nov 9.
The insect repellent N,N-diethyl-3-methylbenzamide (DEET) is widely used and is generally regarded as safe when used according to label instructions. Yet many studies have shown it to be absorbed through the skin. The objective of this study was to determine whether the skin absorption rate of DEET could be decreased while maintaining an evaporation rate consistent with effective repellency. To this end, an aqueous suspension containing 14C-DEET (15%w/w) entrapped in walled polysaccharide microcapsules was prepared and tested for skin absorption in vitro using modified Franz cells maintained in a fume hood. The control formulation was 15%w/w DEET in ethanol. Two doses (3 microL and 5 microL per 0.79 cm2 cell) of each formulation were applied to split-thickness human cadaver skin (n=8/dose), and permeation was monitored for 24h. The microencapsulated DEET formulation lead to a 25-35% reduction of radiolabel permeation compared to the ethanolic DEET formulation. Skin levels of radioactivity at 24h were comparable, indicating that DEET evaporation from the microencapsulated formulation was comparable to or greater than that from ethanol. Hence microencapsulation increased the ratio of DEET evaporation rate to skin penetration rate relative to unencapsulated control in this in vitro study.
驱虫剂N,N-二乙基-3-甲基苯甲酰胺（避蚊胺）被广泛使用，并且按照标签说明使用时通常被认为是安全的。然而，许多研究表明它可通过皮肤吸收。本研究的目的是确定在保持与有效驱蚊效果一致的蒸发速率的同时，避蚊胺的皮肤吸收率是否可以降低。为此，制备了一种含有包裹在有壁多糖微胶囊中的14C-避蚊胺（15%w/w）的水悬浮液，并使用置于通风橱中的改良弗兰兹扩散池在体外测试其皮肤吸收情况。对照制剂为乙醇中15%w/w的避蚊胺。将每种制剂的两个剂量（每0.79 cm2扩散池3 μL和5 μL）施用于人尸体的断层皮肤（每个剂量n = 8），并监测渗透情况24小时。与乙醇避蚊胺制剂相比，微囊化避蚊胺制剂导致放射性标记物渗透降低25 - 35%。24小时时皮肤的放射性水平相当，表明微囊化制剂中避蚊胺的蒸发与乙醇制剂相当或更高。因此，在这项体外研究中，相对于未包封的对照，微囊化提高了避蚊胺蒸发速率与皮肤渗透速率的比率。
