Study on the Influence of Microinjection Molding Processing Parameters on Replication Quality of Polylactic Acid Microneedle Array Product

• Published in: Polymers Vol. 15; no. 5; p. 1199
• Main Authors: Yu, Wenqian, Gu, Junfeng, Li, Zheng, Ruan, Shilun, Chen, Biaosong, Shen, Changyu, Lee, Ly James, Wang, Xinyu
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 27.02.2023; MDPI
• Subjects: Arrays; Biodegradability; Biopolymers; Drug delivery systems; Drugs; Filling; Hypercubes; Injection molding; Latin hypercube sampling; Melt temperature; Microcavities; microinjection mold design; microinjection molding; microneedles; Molds; Needles; PLA; Polylactic acid; Polymer melts; Polyvinyl alcohol; Process parameters; processing parameters; Silicon; Simulation; Vaccines; Vehicles; Viscosity; microinjection mold design; microneedles; processing parameters; PLA; microinjection molding
• ISSN: 2073-4360; 2073-4360
• DOI: 10.3390/polym15051199

Biodegradable microneedles with a drug delivery channel have enormous potential for consumers, including use in chronic disease, vaccines, and beauty applications, due to being painless and scarless. This study designed a microinjection mold to fabricate a biodegradable polylactic acid (PLA) in-plane microneedle array product. In order to ensure that the microcavities could be well filled before production, the influences of the processing parameters on the filling fraction were investigated. The results indicated that the PLA microneedle can be filled under fast filling, higher melt temperature, higher mold temperature, and higher packing pressure, although the dimensions of the microcavities were much smaller than the base portion. We also observed that the side microcavities filled better than the central ones under certain processing parameters. However, this does not mean that the side microcavities filled better than the central ones. The central microcavity was filled when the side microcavities were not, under certain conditions in this study. The final filling fraction was determined by the combination of all parameters, according to the analysis of a 16 orthogonal latin hypercube sampling analysis. This analysis also showed the distribution in any two-parameter space as to whether the product was filled entirely or not. Finally, the microneedle array product was fabricated according to the investigation in this study.