Rapidly separable microneedle patches for controlled release of therapeutics for long-acting therapies

Microneedle (MN) patches have become an appealing approach for transdermal drug delivery due to their unique properties, such as enabling self-administration, causing no pain, increasing patient compliance, eliminating biohazardous sharps disposal and avoiding risk of needle-stick injury. Although dissolvable MN patches have achieved great success in bolus drug delivery in the skin, rapidly separable MN patches have recently attracted strong interest, especially in the treatment of chronic diseases, because of the short application time, long-acting efficacy and less frequent administration. In this review, we summarized three types of rapidly separable long-acting MN patches with different working mechanisms, followed by discussion of biomedical applications of those MN patches, including antigen delivery for vaccination, contraceptives delivery for long-term contraception, insulin delivery for diabetes treatment, ocular drug delivery for long-term therapy of ocular diseases, anti-tumor drug delivery for cancer therapy, pain relief drug delivery for analgesia, drug delivery for bacterial killing, and anti-obesity drug delivery for weight loss. Finally, we provided our perspectives on the future development of rapidly separable long-acting MN patches.