title: Structural characterisation and transdermal delivery studies on sugar microneedles: experimental and finite element modelling analyses.
abstract: Dissolving microneedles are especially attractive for transdermal drug delivery as they are associated with improved patient compliance and safety. Furthermore, microneedles made of sugars offer the added benefit of biomolecule stabilisation making them ideal candidates for delivering biological agents such as proteins, peptides and nucleic acids. In this study, we performed experimental and finite element analyses to study the mechanical properties of sugar microneedles and evaluate the effect of sugar composition on microneedle ability to penetrate and deliver drug to the skin. Results showed that microneedles made of carboxymethylcellulose/maltose are superior to those made of carboxymethylcellulose/trehalose and carboxymethylcellulose/sucrose in terms of mechanical strength and the ability to deliver drug. Buckling was predicted to be the main mode of microneedle failure and the order of buckling was positively correlated to the Young's modulus values of the sugar constituents of each microneedle.
authors.affiliation: Cardiff University, School of Pharmacy, United Kingdom; Cardiff University, School of Engineering, United Kingdom.
authors.forename: Eriketi Z
authors.initials: EZ
authors.lastname: Loizidou
authors.affiliation: Cardiff University, School of Pharmacy, United Kingdom.
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Williams
authors.affiliation: Cardiff University, School of Engineering, United Kingdom. Electronic address: barrow@cardiff.ac.uk.
authors.forename: David A
authors.initials: DA
authors.lastname: Barrow
authors.affiliation: Cardiff University, School of Engineering, United Kingdom.
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Eaton
authors.affiliation: Cardiff University, School of Engineering, United Kingdom.
authors.forename: John
authors.initials: J
authors.lastname: McCrory
authors.affiliation: Cardiff University, School of Engineering, United Kingdom.
authors.forename: Sam L
authors.initials: SL
authors.lastname: Evans
authors.affiliation: Cardiff University, School of Pharmacy, United Kingdom. Electronic address: allendercj@cf.ac.uk.
authors.forename: Chris J
authors.initials: CJ
authors.lastname: Allender
mesh_terms: D000279:Administration, Cutaneous; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D002266:Carboxymethylcellulose Sodium / Q000737:chemistry*; D004187:Disaccharides / Q000737:chemistry*; D016503:Drug Delivery Systems / Q000379:methods; D020342:Finite Element Analysis; D008845:Microinjections / Q000379:methods; D009339:Needles; D004364:Pharmaceutical Preparations / Q000008:administration & dosage*; D012867:Skin / Q000378:metabolism*; D013552:Swine
chemical_list: D001672:Biocompatible Materials; D004187:Disaccharides; D004364:Pharmaceutical Preparations; D002266:Carboxymethylcellulose Sodium
keywords: Buckling; Confocal microscopy; Drug delivery; Skin penetration; Structural mechanics simulations; Sugar microneedles; Von Mises stress; Young’s modulus