Development of solid microneedles for transdermal drug delivery in companion animals

The objective of this paper was to create an economical and abecedarian 3D printing method for the production of solid microneedles, as a more efficient transdermal drug delivery method, for day-to-day use in companion animals. The process of 3D printing was conducted using two types of 3D printers, utilizing the FDM and SLA printing techniques. Modulus of Elasticity was calculated for the determination of mechanical properties of the material, wherethe printed specimen was subjected to axial loading, and deformations were measured using an optical scanner. Post-processing was conducted by washing microneedles in isopropyl alcohol, followed by UV curing. The procedure of testing penetration capabilities was conducted at two sites of cat skin: Auris externa and the lateral part of the abdomen. The SLA printing method was more precise, resulting in higher quality microneedles for animal use compared to the FDM printing technique. Modulus of Elasticity was calculated and the value E=0.9 GPa can be used. Testing proved that the printed model was able to penetrate the skin at the tested sites. The use of microneedles is simple and economical, and therefore has wide applications in small animal practice. Veterinarians can access microneedle design repositories and print them for more effective transdermal drug delivery. The multifunctionality and transferability of the design in the present study ensure that it can be further modified to provide personalized therapy.