title: A scalable fabrication process of polymer microneedles.
abstract: 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.
authors.affiliation: School of Pharmacy, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, People's Republic of China.
authors.forename: Sixing
authors.initials: S
authors.lastname: Yang
authors.forename: Yan
authors.initials: Y
authors.lastname: Feng
authors.forename: Lijun
authors.initials: L
authors.lastname: Zhang
authors.forename: Nixiang
authors.initials: N
authors.lastname: Chen
authors.forename: Weien
authors.initials: W
authors.lastname: Yuan
authors.forename: Tuo
authors.initials: T
authors.lastname: Jin
mesh_terms: D002516:Ceramics / Q000737:chemistry; D006801:Humans; D007328:Insulin / Q000008:administration & dosage / Q000737:chemistry; D055616:Microtechnology / Q000379:methods*; D009339:Needles; D011134:Polysaccharides / Q000737:chemistry; D011142:Polyvinyl Alcohol / Q000737:chemistry*; D014618:Vacuum; D014867:Water / Q000737:chemistry
chemical_list: D007328:Insulin; D011134:Polysaccharides; D014867:Water; D011142:Polyvinyl Alcohol