Department of Pharmaceutical Engineering, Azrieli College of Engineering Jerusalem, Jerusalem 9103501, Israel.
School of Chemistry, Faculty of Exact Sciences, Tel-Aviv University, Tel-Aviv 6997801, Israel.
ACS Appl Bio Mater. 2024 Mar 18;7(3):1682-1693. doi: 10.1021/acsabm.3c01133. Epub 2024 Feb 9.
Microneedle-based drug delivery offers an attractive and minimally invasive administration route to deliver therapeutic agents through the skin by bypassing the stratum corneum, the main skin barrier. Recently, hydrogel-based microneedles have gained prominence for their exceptional ability to precisely control the release of their drug cargo. In this study, we investigated the feasibility of fabricating microneedles from triblock amphiphiles with linear poly(ethylene glycol) (PEG) as the hydrophilic middle block and two dendritic side-blocks with enzyme-cleavable hydrophobic end-groups. Due to the poor formation and brittleness of microneedles made from the neat amphiphile, we added a sodium alginate base layer and tested different polymeric excipients to enhance the mechanical strength of the microneedles. Following optimization, microneedles based on triblock amphiphiles were successfully fabricated and exhibited favorable insertion efficiency and low height reduction percentage when tested in Parafilm as a skin-simulant model. When tested against static forces ranging from 50 to 1000 g (4.9-98 mN/needle), the microneedles showed adequate mechanical strength with no fractures or broken segments. In buffer solution, the solid microneedles swelled into a hydrogel within about 30 s, followed by their rapid disintegration into small hydrogel particles. These hydrogel particles could undergo slow enzymatic degradation to soluble polymers. In vitro release study of dexamethasone (DEX), as a steroid model drug, showed first-order drug release, with 90% released within 6 days. Eventually, DEX-loaded MNs were subjected to an insertion test using chicken skin and showed full penetration. This study demonstrates the feasibility of programming hydrogel-forming microneedles to undergo several mesophase transitions and their potential application as a delivery system for self-administration, increased patient compliance, improved efficacy, and sustained drug release.
基于微针的药物输送提供了一种有吸引力的、微创的给药途径,可以通过绕过皮肤的主要屏障——角质层,将治疗剂递送到皮肤中。最近,水凝胶基微针因其能够精确控制药物货物释放的卓越能力而备受关注。在这项研究中,我们研究了由具有线性聚乙二醇(PEG)作为亲水性中间嵌段和两个具有酶可裂解疏水性末端基团的树枝状侧嵌段的两亲嵌段共聚物制备微针的可行性。由于由纯两亲物制成的微针的形成和脆性较差,我们添加了海藻酸钠基层,并测试了不同的聚合物赋形剂来增强微针的机械强度。经过优化,成功制备了基于两亲嵌段共聚物的微针,并在作为皮肤模拟模型的 Parafilm 中进行测试时,表现出良好的插入效率和低的高度降低百分比。当在 50 至 1000 克(4.9 至 98 mN/针)的静态力下进行测试时,微针表现出足够的机械强度,没有出现断裂或断段。在缓冲溶液中,固体微针在大约 30 秒内膨胀成水凝胶,然后迅速分解成小的水凝胶颗粒。这些水凝胶颗粒可以通过缓慢的酶降解转化为可溶性聚合物。地塞米松(DEX)作为类固醇模型药物的体外释放研究表明药物呈一级释放,90%的药物在 6 天内释放。最终,DEX 负载的 MN 进行了鸡皮插入测试,结果显示完全穿透。这项研究证明了编程水凝胶形成微针以经历几种中间相转变的可行性,以及它们作为自给药、提高患者依从性、提高疗效和持续药物释放的给药系统的潜在应用。
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