Efficient delivery of nanoparticles to deep skin layers using dissolvable microneedles with an extended-length design

Abstract

Dissolvable microneedles with an extended-length design can efficiently deliver NPs to the deep skin layers and prolong the skin retention time of NPs up to 5 days.

Rational Design of Rapidly Separating Dissolving Microneedles for Precise Drug Delivery by Balancing the Mechanical Performance and Disintegration Rate

“…The TDMNs with an extend supporting part instead of separating part could counteract the skin deformation and penetrate into the deeper skin layers, but their drug permeation was still limited. This might be explained that the TDMNs could only partially dissolve within the skin during the application process, thus the initial drug amount deposited into the skin was limited, which consequently restricted the transdermal delivery efficiency . As for RSDMNs, the separating part enabled the drug concentrated tips completely inserted into the skin and formed the drug depot, followed by a sustained permeation profile.…”

“…Monitoring micropores on the skin surface provided a preliminary indication of skin resealing . The pain and skin irritation (pruritus, erythema, and edema) induced by microneedles was highly depended on the insertion depth.…”

“…Fabrication of RSDMNs : RSDMNs were prepared using a multistep centrifugation casting technology . The fabrication procedure was consisted as follows ( Figure ): a) The drug‐loaded tip solution was cast onto the PDMS mold with subsequent centrifugation at 4000 rpm for 3 min at 5 °C to compact the solution into the mold cavities, then the excess matrix solution was removed from the mold surface with a flat blade.…”

“…However, DMNs are difficult to be fully inserted into the skin due to the mechanical weakness of water soluble excipient and the skin deformation under tension . Thus, the complete drug delivery is more likely to be impeded, leading to medication wastage, imprecise dose and limited drug delivery efficiency . Also, it takes many minutes (water soluble materials) or even several days (biodegradable polymers) to wear DMNs patch to ensure drug release, which may result in lower patient compliance and inevitable skin irritation such as erythema and edema .…”

“…Thus, the complete drug delivery is more likely to be impeded, leading to medication wastage, imprecise dose and limited drug delivery efficiency . Also, it takes many minutes (water soluble materials) or even several days (biodegradable polymers) to wear DMNs patch to ensure drug release, which may result in lower patient compliance and inevitable skin irritation such as erythema and edema . To overcome these limitations, many efforts have been developed to simultaneously enhance delivery efficiency and reduce skin irritation.…”