Microneedles with Controlled Bubble Sizes and Drug Distributions for Efficient Transdermal Drug Delivery

Abstract

Drug loaded dissolving microneedles (DMNs) fabricated with water soluble polymers have received increasing attentions as a safe and efficient transdermal drug delivery system. Usually, to reach a high drug delivery efficiency, an ideal drug distribution is gathering more drugs in the tip or the top part of DMNs. In this work, we introduce an easy and new method to introduce a bubble with controlled size into the body of DMNs. The introduction of bubbles can prevent the drug diffusion into the whole body of the MNs. The heights of the bubbles are well controlled from 75 μm to 400 μm just by changing the mass concentrations of polymer casting solution from 30 wt% to 10 wt%. The drug-loaded bubble MNs show reliable mechanical properties and successful insertion into the skins. For the MNs prepared from 15 wt% PVA solution, bubble MNs achieve over 80% of drug delivery efficiency in 20 seconds, which is only 10% for the traditional solid MNs. Additionally, the bubble microstructures in the MNs are also demonstrated to be consistent and identical regardless the extension of MN arrays. These scalable bubble MNs may be a promising carrier for the transdermal delivery of various pharmaceuticals.

Self-Assembly DNA Polyplex Vaccine inside Dissolving Microneedles for High-Potency Intradermal Vaccination

“…The focus of this study is the simple method we developed to load more DNA vaccine into the needle region of MN patch compared with vacuum or centrifugation self-assembly DNA polyplex vaccine formation. Although there are studies presenting effective tip-loaded MN fabrication approaches already 32 , 33 , no one likes our approach which can concentrate the encapsulated DNA vaccine to the needle region of MNs and also form DNA polyplex vaccine in the MNs using one-step fabrication process. To clarify the improvement, we stained the loaded DNA vaccine for porcine circovirus Type 2 (pcDNA4-PCV2) using GelStar™ Nucleic Acid Gel Stain (Lonza Rockland, Inc., Rockland, ME, USA), during which green fluorescence was used to monitor the distribution of DNA vaccine in the MNs.…”

Rapidly separable microneedle patch for the sustained release of a contraceptive

“…Previous studies with microneedle patches of similar dimensions also showed them to be painless 30 . In previous studies, bubbles have been incorporated into microneedle patches to help localize drugs within microneedles, but not to enable rapid microneedle separation 49,50 . Previous studies have also developed patches for rapid microneedle separation, using methods requiring complex, multi-step fabrication 19,24,[51][52][53] .…”

Characterization and Pharmacological Evaluation of Anti-Cellulite Herbal Product(s) Encapsulated in 3D-Fabricated Polymeric Microneedles

“…The mount pushed the MNs against a hard metal surface that was perpendicular to the axis of mount movement. Upon needle failure, the force unexpectedly declined; the ultimate force applied instantly before this decline was recorded as the force of MN failure 52,53 . Data are represented in Table 2 as the mean values (n = 3 ± SD).…”