Rapidly separating microneedles for transdermal drug delivery

• Published in: Acta biomaterialia Vol. 41; pp. 312 - 319
• Main Authors: Zhu, Dan Dan, Wang, Qi Lei, Liu, Xu Bo, Guo, Xin Dong
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.09.2016
• Subjects: Administration, Cutaneous; Animals; Biodegradability; Biodegradable; Biomedical materials; Dissolution; Drug delivery; Drug delivery systems; Drug Delivery Systems - methods; Drugs; In vivo tests; Mechanical Phenomena; Mice, Inbred BALB C; Microinjections; Microneedle; Needles; Permeability; Polyesters - chemistry; Quick separation; Reproducibility of Results; Rhodamines - pharmacology; Skin; Skin - drug effects; Sus scrofa; Quick separation; Drug delivery; Biodegradable; Microneedle
• ISSN: 1742-7061; 1878-7568
• DOI: 10.1016/j.actbio.2016.06.005

Rapidly separating microneedles mount drug-loaded dissolving MNs onto solid PLA MNs of which the separable geometry promise the full insertion and quick separation compared with traditional MNs when inserted into skin. These excellent performances guarantee high delivery efficiency of drugs and after insertion, the removed MN patches can be discarded as household garbages for its biodegradability. [Display omitted] The applications of polymer microneedles (MNs) into human skin emerged as an alternative of the conventional hypodermic needles. However, dissolving MNs require many minutes to be dissolved in the skin and typically have difficulty being fully inserted into the skin, which may lead to the low drug delivery efficiency. To address these issues, we introduce rapidly separating MNs that can rapidly deliver drugs into the skin in a minimally invasive way. For the rapidly separating MNs, drug loaded dissolving MNs are mounted on the top of solid MNs, which are made of biodegradable polylactic acid which eliminate the biohazardous waste. These MNs have sufficient mechanical strength to be inserted into the skin with the drug loaded tips fully embedded for subsequent dissolution. Compared with the traditional MNs, rapidly separating MNs achieve over 90% of drug delivery efficiency in 30s while the traditional MNs needs 2min to achieve the same efficiency. With the in vivo test in mice, the micro-holes caused by rapidly separating MNs can heal in 1h, indicating that the rapidly separating MNs are safe for future applications. These results indicate that the design of rapidly separating dissolvable MNs can offer a quick, high efficient, convenient, safe and potentially self-administered method of drug delivery. Polymer microneedles offer an attractive, painless and minimally invasive approach for transdermal drug delivery. However, dissolving microneedles require many minutes to be dissolved in the skin and typically have difficulty being fully inserted into the skin due to the skin deformation, which may lead to the low drug delivery efficiency. In this work we proposed rapidly separating microneedles which can deliver over 90% of drug into the skin in 30s. The in vitro and in vivo results indicate that the new design of these microneedles can offer a quick, high efficient, convenient and safe method for transdermal drug delivery.