| Summary: | 碩士 === 長庚大學 === 生化與生醫工程研究所 === 104 === In this study, we expected to fabricate polymer-made microneedles (MNs) by stepwise drawing technique (SDT). The impact of morphology of MNs depends on the optimization of SDT, which includes the optimization of dispensing condition of peristaltic pump and drawing process. Multi-parameters adjustment of dispensing condition of MNs array was selected by model test and area of the base analysis. The characteristics of MN fabricated by different composition of dextran/maltose materials were investigated by stereomicroscope and scanning electron microscope.
The results show that MNs with 875.83±54.3μm in height, 801.94±47μm in width and aspect ratio of 1.09 were fabricated by the polymer solution composed of 39% dextran and 1% maltose during 60 second of controlled drawing.
MNs fabricated successfully via controlled drawing method were inserted into porcine cadaver skin to test the insertion capability and it is revealed that the insertion ratio was closed to 100%. In addition, optical coherence tomography (OCT) was used to observe the depth of MN puncture in real-time, the results showed that the penetration depth was about 400μm, which performed the sufficient mechanical strength to penetrate stratum corneum barrier. Furthermore, the skin recovery of porcine cadaver skin after puncture was also investigated by OCT, illustrating that indentation of the porcine cadaver skin tissue induced by MNs can recover after 260 minute.
Rhodamine 6G (R6G)-loaded MN and FITC–insulin loaded MN were inserted into to porcine cadaver skins and to observe the in vitro transdermal delivery profiles by using confocal laser scanning microscope (CLSM). It is showed that the diffusion depth of R6G and FITC–insulin were about 460μm and 300μm after puncture for 10 min, respectively. Furthermore, in vitro transdermal delivery was performed by Franz diffusion cell to determine accumulated release profile of insulin. The result revealed that 88.2±2.69% of insulin was released within 7 hours from MN.
SDT provides easy, convenient, and high-speed fabrication which could reduce MNs drying time and overcome the drawback of volume and drug loss in the 3D mold cavity. Optimization of the parameters of this technique may supply the possibility of MNs mass production in the future.
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