Inkjet printing of insulin microneedles for transdermal delivery

Ross, Steven and Scoutaris, Nikolaos and Lamprou, Dimitrios and Mallinson, David and Douroumis, Dennis (2015) Inkjet printing of insulin microneedles for transdermal delivery. Drug Delivery and Translational Research, 5 (4). pp. 451-461. ISSN 2190-393X (

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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.