Marquardt Kay, Eicher Anna-Carola, Dobler Dorota, Höfer Frank, Schmidts Thomas, Schäfer Jens, Renz Harald, Runkel Frank
Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen, Wiesenstrasse 14, 35390 Giessen, Germany.
Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen, Wiesenstrasse 14, 35390 Giessen, Germany.
Eur J Pharm Biopharm. 2016 Oct;107:80-7. doi: 10.1016/j.ejpb.2016.07.001. Epub 2016 Jul 1.
DNAzymes are catalytic nucleic acid based molecules that have become a new class of active pharmaceutical ingredients (API). Until now, five DNAzymes have entered clinical trials. Two of them were tested for topical application, whereby dermally applied DNAzymes had been prone to enzymatic degradation. To protect the DNAzymes the enzymatic activity of human skin has to be examined. Therefore, the enzymatic activity of human skin was qualitatively and quantitatively analyzed. Activity similar to that of DNase II could be identified and the specific activity was determined to be 0.59Units/mg. These results were used to develop an in vitro degradation assay to screen different kinds of protective systems on human skin. The chosen protective systems consisted of biodegradable chitosans or polyethylenimine, which forms polyplexes when combined with DNAzymes. The polyplexes were characterized in terms of particle size, zeta potential, stability and degree of complexation. The screening revealed that the protective efficiency of the polyplexes depended on the polycation and the charge ratio (ξ). At a critical ξ ratio between 1.0 and 4.1 and at a maximal zeta potential, sufficient protection of the DNAzyme was achieved. The results of this study will be helpful for the development of a protective dermal drug delivery systems using polyplexes.
脱氧核酶是基于催化核酸的分子，已成为一类新型的活性药物成分（API）。到目前为止，已有5种脱氧核酶进入临床试验。其中两种进行了局部应用测试，然而经皮应用的脱氧核酶容易发生酶促降解。为了保护脱氧核酶，必须检测人皮肤的酶活性。因此，对人皮肤的酶活性进行了定性和定量分析。可鉴定出与人DNase II类似的活性，其比活性测定为0.59单位/毫克。这些结果被用于开发一种体外降解试验，以筛选人皮肤上不同类型的保护系统。所选的保护系统由可生物降解的壳聚糖或聚乙烯亚胺组成，它们与脱氧核酶结合时形成多聚体。对多聚体的粒径、zeta电位、稳定性和络合度进行了表征。筛选结果表明，多聚体的保护效率取决于聚阳离子和电荷比（ξ）。在1.0至4.1的临界ξ比和最大zeta电位下，脱氧核酶得到了充分保护。本研究结果将有助于开发使用多聚体的皮肤保护给药系统。
