Fabrication and evaluation of nanoemulsion based insulin loaded microneedles for transdermal drug delivery

<b>Aim:</b> Insulin therapy require self-administration of subcutaneous injection leading to painful and inconvenient drug therapy. The aim is to fabricate nanoemulsion (NE) based insulin loaded microneedles with improved bioavailability and patient compliance. <b>Materials &amp; methods:</b> Different ratios of polyvinyl alcohol and polyvinylpyrrolidone as polymers were prepared through micro-molding technique for microneedles. Characterization of were performed using scanning electron microscope, differential scanning calorimetry, Fourier-transform infrared spectroscopy and circular dichroism. Mechanical strength, hygroscopicity and pain perception of these microneedles were also evaluated. <i>In vitro</i> release, permeation and <i>in vivo</i> PK/PD study of NE-based microneedles were conducted. <b>Results:</b> NE-based microneedles of insulin have improved bioavailability and quick response. <b>Conclusion:</b> Microneedles loaded with insulin can be effectively delivered insulin transdermally to treat diabetes with increased convenience and patient compliance. This study is based on the development of nanoemulsion (NE)-loaded microneedle arrays for transdermal insulin delivery with the objective of effective and painless permeation. NE based insulin loaded microneedles were fabricated using PVA and PVP. Characterization of microneedles using SEM, DSC, FTIR and circular dichroism. Mechanical strength, hygroscopicity and pain perception were evaluated. <i>In vitro</i> permeation using Strat-M membrane and <i>in vitro</i> release studies using rats skin were performed. Comparative <i>in vivo</i> PK/PD studies with standard SC injection and NE were performed showing enhanced insulin bioavailability with rapid hypoglycemic effect.

研究目的：胰岛素治疗需通过皮下注射自行给药，会带来疼痛且用药不便。本研究旨在制备基于纳米乳（nanoemulsion, NE）的载胰岛素微针，以提升药物生物利用度与患者依从性。
材料与方法：以不同比例的聚乙烯醇（polyvinyl alcohol, PVA）与聚乙烯吡咯烷酮（polyvinylpyrrolidone, PVP）作为聚合物，通过微模塑法制备微针。采用扫描电子显微镜（scanning electron microscope, SEM）、差示扫描量热法（differential scanning calorimetry, DSC）、傅里叶变换红外光谱（Fourier-transform infrared spectroscopy, FTIR）与圆二色谱（circular dichroism）对微针进行表征，并评估其机械强度、吸湿性与疼痛感知情况。开展了基于纳米乳的微针的体外释放、透皮渗透与体内药代动力学/药效学（pharmacokinetics/pharmacodynamics, PK/PD）研究。
研究结果：载胰岛素的纳米乳基微针具有更高的生物利用度与更快的响应效果。
研究结论：载胰岛素微针可经皮有效递送胰岛素以治疗糖尿病，且能提升用药便利性与患者依从性。
本研究聚焦于开发载纳米乳（NE）的微针阵列，用于经皮胰岛素递送，目标实现高效无痛透皮给药。采用PVA与PVP制备了基于纳米乳的载胰岛素微针。通过SEM、DSC、FTIR与圆二色谱对微针进行表征，并评估其机械强度、吸湿性与疼痛感知。采用Strat-M膜开展体外透皮渗透实验，以大鼠皮肤为介质开展体外释放研究。与标准皮下注射及纳米乳制剂进行对比体内PK/PD研究，结果显示该制剂可提升胰岛素生物利用度，且能快速产生降糖效果。