| Summary: | 碩士 === 國立清華大學 === 奈米工程與微系統研究所 === 99 === Transdermal delivery is an attractive alternative of drug delivery. Comparing to the conventional drug delivery techniques using pills or injections, this approach avoids degradation in the gastrointestinal tract and the pain of injections. But it is limited by the low permeability of skin because the stratum corneum (SC) in the upper skin (10-20 μm) is the main barrier. Hence, we used the Bio-MEMS technique to make microneedle array patch to inset into skin. This microneelde array patch could easily cross the SC but not so long that reach the deeper tissue and simulate nerves to developed a convenient, pain-free, and high efficient transdermal delivery patch.
In this study, we present a novel approach to transdermal drug delivery that is two-step controlled-release system based on the skin cancer application. We used fluorescent dyes as model drugs to simulate the slow effect of anti-cancer drug and short half-time of anesthesia and vasoconstrictor. First, we used backside exposure technology of UV-lithography to fabricate microneedle array mold and bio-available PVP polymer with 1st model drug as the microneedle array materal. Second, we used double emulsion technology to fabricate pH-sensitive PLGA HMS (Hollow Micro-Spheres) with 2nd model drug. Sequentially, we combined these two techniques to fabricate the two-step controlled-release microneedle patch.
This microneedle patch was shown two-step releasing profiles in vitro, the insertion capability ex vivo, and the transcutaneous delivery in vivo. As a consequence, we conclude that the two-step controlled-release can release two drugs with a time difference to the skin.
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