Thermal ablation of separable microneedles for transdermal delivery of metformin on diabetic rats

The separable microneedles (MNs), consisted of upper metformin-loaded PCL arrowheads and lower PVA/PCL supporting array, have been fabricated by separately molding method. The metformin-loaded and thermal ablation MNs arrowheads were capped on dissolving solid supporting array. The as-fabricated MNs exhibited an excellent thermal ablation change due to the low melting point of PCL. After insertion into the skin, the upper separable MNs arrowheads could be embedded into the skin. When the separable MNs arrowheads were exposed to thermal stimulus, causing the PCL MNs arrowheads to melt and enabling the release of encapsulated metformin to be thermally modulated.