Microneedles for oral mucosal delivery – Current trends and perspective on future directions

ABSTRACTIntroduction Oral cavity drug and vaccine delivery has the potential for local targeting, dose reduction, minimization of systemic side effects, and generation of mucosal immunity. To overcome current limitations of delivery into the oral cavity mucosa, microneedles (MNs) have emerged as a promising technology.Areas covered We reviewed the literature on MN application in the oral cavity, including in vitro studies, in vivo animal studies, and human clinical trials.Expert opinion MNs are sufficiently robust to cross the oral cavity epithelium and nearly painless when applied to different parts of the human oral mucosa including the lip, cheek, tongue and palate. In recent years, MNs have been evaluated for different applications, including vaccination, topical anesthetic delivery, and treatment of local oral pathologies such as oral lesions or carcinomas. MNs are attractive because they have the potential to produce a better treatment outcome with reduced side effects. Over the coming years, we project a significant increase in research related to the development of MNs for use in dentistry and other medical conditions of the mouth.KEYWORDS: AdministrationDentistryDrug carriersDrug delivery systemsMouth MucosaDisclaimerAs a service to authors and researchers we are providing this version of an accepted manuscript (AM). Copyediting, typesetting, and review of the resulting proofs will be undertaken on this manuscript before final publication of the Version of Record (VoR). During production and pre-press, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal relate to these versions also. Article highlightsMicroneedles offer an innovative platform to deliver therapeutics, vaccines and detection agents into the oral mucosa.Like the skin, microneedles have been found to be nearly painless when inserted into the mouth of human volunteers.Microneedles have been used to deliver a broad range of substances into the oral cavity including, small molecules, proteins, antibodies, virus particles, and nanoparticles, and span many applications including vaccination, oral cancer detection and treatment, mouth ulcer treatment, and management of pain for dentistry.About 73% of the published articles have used in vivo models to evaluate microneedles in the oral cavity, and they provide strong evidence of their effectiveness in producing therapeutic effects and immune responses.The body of literature on the use of microneedles in the oral cavity is small but growing, and there is need for increased research for future innovations and clinical product development.Declaration of interestHS Gill is a co-inventor on patents related to use of microneedles. This potential conflict of interest has been disclosed and is managed by Texas Tech University. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.Reviewer disclosuresPeer reviewers on this manuscript have no relevant financial or other relationships to disclose.Additional informationFundingThis research was supported in parts by National Institutes of Health under Award Number [R01AI135197] (HS Gill) and endowment funds of Whitacre Endowed Chair in Science and Engineering (HS Gill).