RESUMO
3D printed microneedle arrays were fabricated using a biocompatible resin through stereolithography (SLA) for transdermal insulin delivery. Microneedles were built by polymerising consecutive layers of a photopolymeric resin. Thin layers of insulin and sugar alcohol or disaccharide carriers were formed on the needle surface by inkjet printing. The optimization of the printing process resulted in superior skin penetration capacity of the 3D printed microneedles compared to metal arrays with minimum applied forces varying within the range of 2 to 5â¯N. Micro-CT analysis showed strong adhesion of the coated films on the microneedle surface even after penetration to the skin. In vivo animal trials revealed fast insulin action with excellent hypoglycaemia control and lower glucose levels achieved within 60â¯min, combined with steady state plasma glucose over 4â¯h compared to subcutaneous injections.
Assuntos
Sistemas de Liberação de Medicamentos , Insulina/administração & dosagem , Agulhas , Impressão Tridimensional , Estereolitografia , Administração Cutânea , Animais , Glicemia/metabolismo , Bovinos , Diabetes Mellitus Experimental/sangue , Diabetes Mellitus Experimental/tratamento farmacológico , Liberação Controlada de Fármacos , Feminino , Insulina/farmacocinética , Insulina/farmacologia , Insulina/uso terapêutico , Camundongos , Absorção Cutânea , Análise Espectral Raman , Suínos , Microtomografia por Raio-XRESUMO
In this study, polymeric microneedle patches were fabricated by stereolithography, a 3D printing technique, for the transdermal delivery of insulin. A biocompatible resin was photopolymerized to build pyramid and cone microneedle designs followed by inkjet print coating of insulin formulations. Trehalose, mannitol and xylitol were used as drug carriers with the aim to preserve insulin integrity and stability but also to facilitate rapid release rates. Circular dichroism and Raman analysis demonstrated that all carriers maintained the native form of insulin, with xylitol presenting the best performance. Franz cell release studies were used for in vitro determination of insulin release rates in porcine skin. Insulin was released rapidly within 30â¯min irrespectively of the microneedle design. 3D printing was proved an effective technology for the fabrication of biocompatible and scalable microneedle patches.