Microneedles are emerging drug delivery methods for painless treatment. The current study tested dissolving microneedles containing lidocaine (Li-DMN) for use in local anesthesia. An Li-DMN patch was fabricated by centrifugal lithography with carboxymethyl cellulose as a structural polymer and assessed for physical properties by optical microscopy and a fracture force analyzer. The biocompatibility was evaluated by a histology section in vitro and by ear thickness in vivo. The efficacy of the Li-DMN patch was assessed by electrophysiological recordings in primary cultured sensory neurons in vitro and a von Frey test on rats’ hind paws in vivo. The physical properties of the microneedle showed enough rigidity for transdermal penetration. The maximal capacity of lidocaine-HCl in the Li-DMN patch was 331.20 ± 6.30 µg. The cytotoxicity of the dissolving microneedle to neuronal cells was negligible under an effective dose of lidocaine for 18 h. Electrophysiological recordings verified the inhibitory effect of the voltage-gated sodium channel current by the Li-DMN patch in vitro. A skin reaction to the edema test and histologic analysis of the rats’ ears after application of the Li-DMN patch were negligible. Also, the application of the Li-DMN patch reduced the nocifensive behavior of the rats almost immediately. In conclusion, the dissolving microneedle patch with carboxymethyl cellulose is a promising candidate method for the painless delivery of lidocaine-HCl.
Bibliographical noteFunding Information:
Acknowledgments: Chisong Lee is grateful for financial support from the Hyundai Motor Chung Mong-Koo Foundation.
Funding: This research was funded by the National Research Foundation of Korea (NRF) grant (NRF-2018R1D1A1B07049067) and by the Korea Health Technology R&D Project (HI16C0625) through the Korea Health Industry Development Institute (KHIDI), the Republic of Korea (MSIP and MoHW).
© 2020 by the authors. Licensee MDPI, Basel, Switzerland.
All Science Journal Classification (ASJC) codes
- Pharmaceutical Science