3D printed hollow microneedles array using stereolithography for efficient transdermal delivery of rifampicin

A 3D printed assembly of hollow microneedles (HMNs) array, conjoined with a reservoir void, was designed and additively manufactured using stereolithography (SLA) technology utilizing a proprietary class-I resin. The HMNs array was utilized for transdermal delivery of high molecular weight antibiotics, i.e., rifampicin (Mw 822.94 g/mol), which suffers from gastric chemical instability, low bioavailability, and severe hepatotoxicity. HMNs morphology was designed with sub-apical holes present in a quarter of the needle tip to improve its mechanical strength and integrity of the HMNs array. The HMNs array was characterized by optical microscopy and electron microscopy to ascertain the print quality and uniformity across the array. The system was also subjected to mechanical characterization for failure and penetration analyses. The ex vivo permeation and consequent transport of rifampicin across porcine skin were systematically evaluated. Finally, in vivo examina-tions of rifampicin administration through the microneedle reservoir system in SD rats revealed efficient penetration and desired bioavailability.

Automated summary

A 3D printed assembly of hollow microneedles, designed and manufactured using stereolithography technology, was used for transdermal delivery of high molecular weight antibiotics. The microneedles were designed with sub-apical holes for improved mechanical strength, and were characterized for quality and uniformity. Ex vivo and in vivo experiments confirmed the efficient penetration and desired bioavailability of the antibiotic.