School of Pharmacy, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, People's Republic of China.
Int J Nanomedicine. 2012;7:1415-22. doi: 10.2147/IJN.S28511. Epub 2012 Mar 12.
While polymer microneedles may easily be fabricated by casting a solution in a mold, either centrifugation or vacuumizing is needed to pull the viscous polymer solution into the microholes of the mold. We report a novel process to fabricate polymer microneedles with a one-sided vacuum using a ceramic mold that is breathable but water impermeable. A polymer solution containing polyvinyl alcohol and polysaccharide was cast in a ceramic mold and then pulled into the microholes by a vacuum applied to the opposite side of the mold. After cross-linking and solidification through freeze-thawing, the microneedle patch was detached from the mold and transferred with a specially designed instrument for the drying process, during which the patch shrank evenly to form an array of regular and uniform needles without deformation. Moreover, the shrinkage of the patches helped to reduce the needles' size to ease microfabrication of the male mold. The dried microneedle patches were finally punched to the desired sizes to achieve various properties, including sufficient strength to penetrate skin, microneedles-absorbed water-swelling ratios, and drug-release kinetics. The results showed that the microneedles were strong enough to penetrate pigskin and that their performance was satisfactory in terms of swelling and drug release.
虽然聚合物微针可以通过在模具中浇铸溶液来轻松制造，但需要离心或真空将粘性聚合物溶液吸入模具的微孔中。我们报告了一种使用透气但不透水的陶瓷模具通过单边真空制造聚合物微针的新工艺。将含有聚乙烯醇和多糖的聚合物溶液浇铸在陶瓷模具中，然后通过施加在模具另一侧的真空将其吸入微孔中。通过冷冻-解冻进行交联和固化后，将微针贴片从模具上取下，并使用专门设计的仪器进行干燥处理，在此过程中，贴片均匀收缩，形成一系列规则且均匀的针，不会变形。此外，贴片的收缩有助于减小针的尺寸，从而便于男性模具的微加工。最后将干燥的微针贴片冲压成所需的尺寸，以实现各种特性，包括足够的强度穿透皮肤、微针吸收水的膨胀率和药物释放动力学。结果表明，微针足以穿透猪皮，并且在膨胀和药物释放方面表现令人满意。
