title: Inkjet printing of insulin microneedles for transdermal delivery.
abstract: Inkjet printing technology was used to apply insulin polymeric layers on metal microneedles for transdermal delivery. A range of various polymers such as gelatin (GLN), polyvinyl caprolactame-polyvinyl acetate-polyethylene glycol (SOL), poly(2-ethyl-2-oxazoline) (POX) and trehalose (THL) were assessed for their capacity to form thin uniform and homogeneous layers that preserve insulin intact. Atomic force microscopy (AFM) showed homogeneous insulin-polymer layers without any phase separation while SOL demonstrated the best performance. Circular discroism (CD) analysis of rehydrated films showed that insulin's alpha helices and β-sheet were well preserved for THL and SOL. In contrast, GLN and POX insulin layers revealed small band shifts indicating possible conformational changes. Insulin release in Franz diffusion cells from MNs inserted into porcine skin showed rapid release rates for POX and GLN within the first 20 min. Inkjet printing was proved an effective approach for transdermal delivery of insulin in solid state.
authors.affiliation: Faculty of Engineering and Science, University of Greenwich, Medway Campus, Chatham Maritime, Kent, ME4 4TB, UK.
authors.forename: Steven
authors.initials: S
authors.lastname: Ross
authors.forename: Nicolaos
authors.initials: N
authors.lastname: Scoutaris
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Lamprou
authors.forename: David
authors.initials: D
authors.lastname: Mallinson
authors.forename: Dennis
authors.initials: D
authors.lastname: Douroumis
mesh_terms: D000279:Administration, Cutaneous; D000818:Animals; D016503:Drug Delivery Systems / Q000295:instrumentation*; D065546:Drug Liberation; D004355:Drug Stability; D004867:Equipment Design; D007004:Hypoglycemic Agents / Q000008:administration & dosage*; D066298:In Vitro Techniques; D007328:Insulin / Q000008:administration & dosage*; D008845:Microinjections / Q000295:instrumentation*; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D009339:Needles; D011108:Polymers / Q000737:chemistry; D012867:Skin / Q000378:metabolism; D013552:Swine; D013678:Technology, Pharmaceutical / Q000295:instrumentation / Q000379:methods*
chemical_list: D007004:Hypoglycemic Agents; D007328:Insulin; D011108:Polymers