Microneedle/CD-MOF-mediated transdural controlled release of methylprednisolone sodium succinate after spinal cord injury

A new method of transdural delivering drugs to the spinal cord has been developed, involving the use of microneedles (MNs) and a β-cyclodextrin metal-organic framework (CD-MOF). This epidural microneedle array, dubbed MNs@CD-MOF@MPSS, can be utilized to deliver methylprednisolone sodium succinate (MPSS) to the site of spinal cord injury (SCI) in a controlled manner. MNs allows to generate micropores in the dura for direct drug delivery to the spinal cord, overcoming tissue barriers and targeting damaged regions. Additionally, the CD-MOF provides a secondary extended release after separating from the MNs. In in vitro study, inward MNs increased cellular absorption of MPSS and then reduced LPS-induced M1 polarization of microglia. And animal studies have shown that this method of drug delivery results in improved BMS scores and a reduction in M1 phenotype microphage and glial scar formation. Furthermore, the downregulation of the NLRP3-positive inflammasome and related pro-inflammatory cytokines was observed. In conclusion, this new drug platform has potential for clinical application in spinal cord diseases and is a valuable composite for minimally transdural controlled drug delivery. STATEMENT OF SIGNIFICANCE: This research presents a new epidural microneedle patch made up of microneedles (MNs) and a β-cyclodextrin metal-organic framework (CD-MOF). The epidural microneedle patch boasts high drug loading capacity, the ability to penetrate the dura, and controlled release. When loaded with methylprednisolone sodium succinate (MPSS), it effectively reduces inflammation and improves neurological function after spinal cord injury. Therefore, it is a novel and promising drug platform for the treatment of spinal cord diseases in a clinical setting.