Structural optimization of rapidly separating microneedles for efficient drug delivery

Rapidly separating microneedles (RSMNs) arose as an improvement of traditional MNs for the special separable structures. The aim of this study was to investigate various structural parameters contributed to the delivery performance of RSMNs. The experimental results indicated that the optimized RSMNs with 500 μm-long solid PLA MNs, 250 μm-long overlap and 500 μm-long dissolving MNs delivered over 95% of drugs within 30 s. In the in vivo diabetic mice treatment, insulin loaded optimized RSMNs reached approximately the same therapeutic effect on lowering the glucose in blood as injection, significantly better than traditional MNs.